GEOLOGY OF THE PRECAMBRIAN ROCKS OF THE
LEMITAR MOUNTAINS,
SOCORRO C O U N T Y , NEW M E X I C O
V i r g i n i a T.
Submittedin
McLemore
Partial Fulfillmept
o f t h er e q u i r e m e n t sf o rt h eD e g r e eo f
Master of S c i e n c e i n G e o l o g y
V
New M e x i c o I n s t i t u t e
o f M i n i n ga n dT e c h n o l o g y
Socorro, N e w M e x i c o
May, 1980
TABLE OF CONTENTS
ABSTRACT
ACKNOWLEDGMENTS.
INTRODUCTION
Purpose
Methods
.............................................. 1
.............................................. 3
of
............................. 4
........................................ 6
......................................... 7
......................................... 7
of
U n i t ...........11
Investigation
P r e v i o u s Work
SEDIMENTARYROCKS
Introduction
Distribution and discussion
Distribution and discussion
Lower
of U p p e r U n i t
...........12
........................................
P r o v e n a n c e a n d S e d i m e n t a t i o n ........................
IGNEOUSROCKS ............................................
I n t r o d u c t i o n ........................................
L e m i t a r d i o r i t e j g a b b r o..............................
I n t r o d u c t i o n ...................................
D e s c r i p t i o n ....................................
M i g m i t i z a t i o n ..................................
G e o c h e m i s t r y ....................................
G a b b r o o f G a r c i a C a n y o n ........................
O r i g i n .........................................
M a f i c D i k e s .........................................
Geochemistry
20
25
31
31
33
33
35
40
44
46
4.
48
................................... 48
D e s c r i p t i o n ....................................
49
G e o c h e m i s t r y ...................................
53
O r i g i n of t h e M a f i c R o c k s ...........................
54
G r a n i t i c Complex ....................................
57
I n t r o d u c t i o n ....................................
57
G n e i s s i c g r a n i t e ...............................
59
M u s c o v i t e - b i o t i t e g r a n i t e ......................
61
B i o t i t e g r a n i t e ................................
63
L e u c o g r a n i t e ...................................
65
P o l v a d e r a G r a n i t e ................................
65
Pegmatites and quartz veins
.................... 68
G e o c h e m i s t r y ...................................
69
O r i g i n .........................................
~4
C a r b o n a t i t e D i k e s ...................................
76
I n t r o d u c t i o n ...................................
76
D i s t r i b u t i o n ...................................
77
D e s c r i p t i o n ....................................
87
G e o c h e m i s t r y ...................................
98
F e n i t i e a t i o n ..................................
104
O r i g i n ........................................
114
STRUCTURE AND METAMORPHISM ..............................
117
MINERALIZATION ..........................................
127
HISTORY. TECTONIC SETTING. AND CONCLUSIONS .....1 3 0
Distribution
I
GEOLOGIC
REFERENCES CITED........................................l36
APPENDICES
..........................
A
-
Analytical
B
-
Brief Petrographic Description of the
Procedures
149
Analyzed Rocks.................................157
C
-
Chemical
..............................
Analyses
162
TABLES
1
2
3
4
5
6
7
8
.G e o c h e m i s t r y o f s a n d s t o n e s .........................
21
- Chemical c l a s s i f i c a t i o n o f s a n d s t o n e s ..............2 3
- G e o c h e m i s t r y o f L e m i t a r s e d i m e n t s ..................2 9
- Difference between gabbro and diorite
..............36
- C h e m i s t r y of t h e m a f i c r o c k s .......................
45
- C h e m i s t r y of t h e L e m i t a r g r a n i t i c c o m p l e x ..........7 0
-
10 11 9
Chemistry of granites
..............................
MineralsofCarbonatiteComplexes
73
..................78
.......................... 79
element chemistry of carbonatites
............80
Chemistry of.carbonatites
Trace
S i m i l a r i t i e sa n dd i f f e r e n c e s
Lemitar c a r b o n a t i t e s
..............8 2
1 2 - X-Ray d i f f r a c t i o n l i n e s o f b a s t n a e s i t e
............83
1 3 - M i n e r a l o g y o f t h e L e m i t a r c a r b o n a t i t e s .............89
14 - Distribution of elements
i n c a r b o n a t i t e s ..........1 0 2
1 5 - M i n e r a l s o f t h e L e m i t a r c a r b o n a t i t e s a m p l e s .......1 0 3
1 6 - C l a s s i f i c a t i o n of f e n i t e s .........................
105
1 7 - Summary o f c h e m i c a l c h a n g e s d u e t o f e n i t i z a t i o n
...1 0 9
and other occurrences of carbonatites
18
-
Chemicaltrends
19
-
Summary of geologic history
..........110
....................... 1 3 1
of f e n i t i z e d m a f i c r o c k s
FIGURES
1
2
.I n d e x map ...........................................
- P r e c a m b r i a ng e o l o g i c map of t h e Lemitar M o u n t a i n s
2
(inpocket)
3
-
Diagrammatic stratigraphic section
4
-
Classification of sandstones
5
-
6
7
-
Na20
K20 p l o t o f s a n d s t o n e s
Geochemical classification
..................8
........................
......................
of
...........
22
sandstones
22
Tectonic provenance of Proterozoic sandstones
......2 6
....................
9
AFM d i a g r . a m ........................................
1 0 - M a f i c - F e l s i c i n d e x d i a g r a m .......................
8
11
12
13
-
C l a s s i f i c a t i o n of igneous rocks
-
CaO
Rb
-
Na20
-
K20 d i a g r a mo f
Srdiagramof
L e m i t a r i g n e o u sr o c k s ' . .
Lemitar g r a n i t i c c o m p l e x
C a r b o n a t e - a p a t i t e - m a g n e t i t ep l o to ft h e
carbonatites
9
32
55
56
71
........7 2
Lemitar
.......................................
.....................
......................
88
14
-
Chemical plot of carbonatites
100
15
-
CaO-Na20-K20
108
p l o t of f e n i t e s
PLATES
1
2
.P h o t o g r a p h . a r k o s e a n d q u a r t z i t e ...................14
- P h o t o g r a p h . c r o s s b e d d i n g i n a r k o s e .................14
............................ 1 6
................................. 1 6
......................... 1 8
.................... 38
......................... 38
......................... 39
.....4 1
in
.....4 1
3 .P h o t o m i c r o g r a p h . a r k o s e
5
-
6
-
Photomicrograph. dioritelgabbro
7
-
Photograph. dioritelgabbro
4
9 10 11 12 13 14 8
Photograph. arkose
Photomicrograph. subarkose
Photograph. dioritelgabbro
Photograph. foliated muscovite-biotite granite
Photograph. migmatitic layer
dioritelgabbro
Photograph. agmatitic structure
i n dioritelgabbro
Photograph. agmatitic structure in dioritelgabbro
..4 2
..4 2
i n diorite/gabbro.,43
P h o t o g r a p h .b o u d i n a g es t r u c t u r e
Photomicr.ograph, altered mafic dike
................5 1
..................6 0
15
-
16
.P h o t o g r a p h . g n e i s s i c g r a n i t e
17
.P h o t o m i c r o g r a p h . m u s c o v i t e - b i o t i t e g r a n i t e
Photomicrograph. gneissic granite
.......................
.........64
...................64
...............84
.....:......... 84
................86
62
18 .P h o t o m i c r o g r a p h . b i o t i t e g r a n i t e
1 9 .P h o t o g r a p h . b r e c c i a c a r b o n a t i t e d i k e
20
-
21
.P h o t o g r a p h . b a n d e d c a r b o n a t i t e d i k e
22
.P h o t o m i c r o g r a p h . p r i m a r y c a r b o n a t i t e d i k e
Photograph. breccia carbonatite dike
24
..........9 0
.P h o t o m i c r o g r a p h . r e p l a c e m e n t c a r b o n a t i t e d i k e
......9 1
- Photomicrograph.replacementcarbonatitedike
......9 1
25
.P h o t o g r a p h . c a r b o n a t i t e d i k e
26
-
23
....................... 93
..................9 4
Photomicrograph. carbonatite dike
27
-
28
29
Photograph, carbonatite dike
.......................
P h o t o g r a p h ,c a r b o n a t i t e
dike.......................97
P h o t o g r a p h ,c a r b o n a t i t e
dike.......................97
MAPS
1
2
-
G e o l o g i c Map o f t h eP r e c a m b r i a nr o c k s
G e o l o g i c Cross S e c t i o n s
( i n pocket)
(in p o c k e t )
94
ABSTRACT
T h eP r e c a m b r i a nr o c k si nt h eL e m i t a rM o u n t a i n sc o n s i s t
of
a
sequenco
e sf e d i m e n t st,h C
e orkscrew
C a n y oSne q u e n c e
( 5 % ) , i n t r u d e ds e q u e n t i a l l yb ym a f i cd i k e s ,
a diorite/gabbro
( 7 5 % ) , a ncda r b o n a t i tdei k e s .
b o d(y2 0 % g
) ,r a n i t irco c k s
a Lower U n i t composed o f a
T h es e d i m e n t sc o n s i s to f
of
a r k oaU
sanenpdpUe n
cr o
i tm p o s e d
i n t e r b e d daendd
f o l i a t e da r k o s e s ,s u b a r k o s e s ,a n dq u a r t z i t e s .
The s e d i m e n t s
l o w S i 0 2 / A 1 2 0 3r a t i o sa n d
i n S i 0 2 ( > 6 2 % ) a n dh a v e
a r eh i g h
K20/Na20 r a t i o se q u a lt oo rg r e a t e rt h a no n e .
o fq u a r t za n df e l d s p a ri n d i c a t e s
g r a n i t e or
fluvial
massive
T h ea b u n d a n c e
a s o u r c ea r e ac o n s i s t i n go f
a
g n e i sw
s ,h i b
l ee d d i ns gt r u c t u r ei ns d i c a t e
a continental-rift
or d e l t a i ce n v i r o n m e n ti ne i t h e r
o r a r a p i d l y r i s i n g c o n t i n e n t a l - m a r g i ns e t t i n g .
The
Lemitar
diorite/gabbro
a
is
lithologically
mafic u n i tr a n g i n gi nc o m p o s i t i o nf r o mg a b b r o
heterogeneous
( > A n 5 0a )nddi o r i t( e< A n 5 0tq1ou a r tgza b b raonqdu a r t z
d i o r i t e (5-10% q u a r t z ) .T h i sl i t h o l o g i ch e t e r o g e n e i t yc o u l d
abcec o u n t e d
gabbroic
for
magma
late
be yi t h e r
pre-granite,
-
Stage
I,
of
11,
and post-granite).
and
a
o f g r a n i t i c magmas
o ir n j e c t i o na n dm i x i n g
w i t h a g a b b r o bi co d T
y .h r es et a g e s
recognized
d i f f e r e n t i a t i o nf
m a f di ci k e s
are
I11 ( p r e - d i o r i t e / g a b b r o ,
T h em a f i cr o c k sp l o ti nt h e
tholeiite field
o f a n AFM d i a g r a m .
six
T h eg r a n i t i cr o c k sa r eg r o u p e di n t o
one
or
-
m o rpe l u t o n s
v a r i a t i o n so f
gneissig
c r a n i t em
, uscovite-biotite
g r a n i t eb, i o t i t e
g r a n i t el, e u c o g r a n i t eP, o l v a d e r a
granite,
a n dp e g m a t i t e sa n dq u a r t zv e i n s .
Age r e l a t i o n s h i p sb e t w e e n
t h eg r a n i t i cr o c k sa r eu n c e r t a i nb e c a u s et h eg r a n i t e sa r e
are of a
n oicn
to n t a cwt i tohnaen o t h earnpdr o b a b l y
similar a g eT.hger a n i t ir co c k s
fall
-
into
wgor o u p s
G r o u p I ( g n e i s s i cg r a n i t ea n db i o t i t eg r a n i t e )c h a r a c t e r i z e d
by
low
S i(0626 - 7 0ah2ni)dg h
CaO
(0.8-1.5%
aG
n)dr o u p .
I1
(1.5-32)
MgO
( m u s c o v i t e - b i o t igt er a n i t e .
and
(73-76%) a n d
P o l v a d e r ag r a n i t e c) h a r a c t e r i z e db yh i g hS i 0 2
l o w C a O ( < 1 . 5 % )a n d
and
MgO ( < 0 . 8 % ) .
C a r b o n a t i t ed i k e si n t r u d et h ee a r l i e rP r o t e r o z o i cr o c k s
and
are
c o m p o s>o
e 5fd 0c%
a r b o n a(tcea l c i tdeo, l o m i t e ,
a n d / oa rn k e r i t ea )n d
magnetite
are
( u pt o
T h ec a r b o n a t i t e s
rich
in
lo$),
a p a t i t(eutpo
15%), a n db i o t i t e / p h l o g o p i t e( u pt o
f a l l i n t ot w op o p u l a t i o n s
-
15%).
l o wi r o na n d
h i igrhorne ,l a t tpehordee s e naocnfek e r iatne d
4%
m a g n e t i t eC. a r b o n a t i t e as r rei c ihp
n h o s p h o r u (su tpo
P 2 0a5un)r d
,a n i (u
tu
omp
0.1%
U308).
Norm
s oadl i c
f e n i t i z a t i o nh a sa l t e r e dt h eL e m i t a rd i o r i t e / g a b b r oa d j a c e n t
t ot h ec a r b o n a t i t ed i k e s
a s e v i d e n c e d by t h ei n c r e a s ei n
sodium i n p l a g i o c l a s e s a n d t h e i n c r e a s e i n K - f e l d s p a r .
C h e m i c a l l y ,t h ei g n e o u sr o c k s
populations
-
f a l l i n t ot h r e ed i s t i n c t
t h em a f i cr o c k s ,t h eg r a n i t i cr o c k s ,a n dt h e
c a r b o n a t i t e sn; o
c h e m i c atlr e n d as r ae p p a r e nbt e t w e e n
the
is consistent
o f t h e sreo c k s
groupT
s .hbei m o d anla t u r e
w i t h a c o n t i n e n t a l - r i f ts e t t i n g .
T hPer e c a m b r i arno c kotsfhLee m i t aM
r o u n t a i nhsa v e
of
u n d e r g osnuec c e s s ipveer i o d s
and
r e t r o g r amdeet a m o r p h i s m
m e t a m o r p h i sp m
r it oo r
o t hael rt e r a t iaoannrde
s t r u c t u r a lcloym p l ecxo,n s i s t fioo
nflgi a t i of na ,u l t s ,
s h e a r i n ga,n bd r e c c i a t i o (nm o sotw
f h i c ahrL
e a r a m i doe r
1.
T e r t isat rr yu c t u r e s
P r o t e r o z ori oc c k s
are
M i naesr sael m btlhaoegf e. s
representative
of
t ht er a n s i t i o n
b e t w e e tnh ge r e e n s c h i sat n ad m p h i b o l i t fea c i e sF. o l i a t i o n
ot h
fCe o r k s c r e C
w a n y osne q u e n caep p r o x i m a t e lpya r a l l e l s
i s d i s t i n g u i s h e d by t e x t u r a la n dc o l o r
relicb
t e d d i n ga n d
contrasts.
A n o r t h e a s t - t r e n d i n gs h e a rz o n ec u t sa c r o s st h e
at
s e d i m e nat n
es d
nds
t hi en t r u s i vceo n t a cwt i t. ht h e
-.
m u s c o v i t e - b i o t i tger a n i t eS. h e a r i nogt fhdei o r i t e l g a b b r o
may b e r e l a t e d t o t h e e m p l a c e m e n t
of t h e& r a n i t i cr o c k s .
D e t a i l e dm a p p i n g ,p e t r o g r a p h i c ,a n dg e o c h e m i c a ls t u d i e s
i n d i c a t et h a t h eP r o t e r o z o i cr o c k sa r ec o n s i s t e n w
t ith
c o n t i n e n t a l - r i fst e t t i n g .
b e t w e e nt h e
T h e l a c k of
a ncyh e m i c at lr e n d
m a f i c , g r a n i t i c ,a n dc a r b o n a t i t eg r o u p ss u g g e s t s
t htaht e artrehe r se ee p a r a t e
magma
s o u r cfetoh
sre
a
formation
of
i g n e oruosc k s
in
Lemitar
the
Mountains.
H o w e v e r ,c o n t a m i n a t i o nb yc r u s t a lm a t e r i a la n do t h e r
c o u l db er e s p o n s i b l ei np a r t
trend.
for t h i sl a c k
An a l k a l i p r o v i n c e may h a v e x i s t e d
a n ds o u t h e r nC o l o r a d o e, v i d e n c e d
magmas
o f a n yc h e m i c a l
in
New
by t h ep r e s e n c e
and
New
Mexico
(Monte
t o
Largo,
Lemitar
F l oM
r ioduan t aPianj sa
M
,r o
i tuon t T
a ihne) .
M o u n t a i n sw o u l db ep a r t
of 0 . 4
(Wet
1 . 2 b a ya .l k a rl io c kssc a t t e r etdh r o u g h o uCt o l o r a d o
M o u n t a i n Isr, oM
nountains)
Mexico
of t h i sa l k a l ip r o v i n c e .
ACKNOWLEDGMENTS
T h e a u t h o r i s i n d e t)te d t 'o Mr.
f o ar c c e s tstoh e
B.
J.
a n d Mrs.
f i e l d a r e aS.p e c i a lc k n o w l e d g m e n t
made t o D r .
K.
C.
C o n d i ef o r
as d u r i n g t h e p r e p a r a t i o n
T haeu t h o r
as w e l l
J o aPne n d l e t o n ,
'J.
M.
of t h e m a n u s c r i p t .
i s g r a t e f u lt o
some
of
is
many h e l p f u sl u g g e s t i o n a
s nd
commentspertainingtothefieldandlaboratorywork
helw
p ith
Kelley
J.
Dr.
R.
R e n a u l ft o hr i s
t h ae n a l y t i c aal n a l y s i sR
. o b e rN
t orth,
Drs.'
K.
C.
C o n d i e , J.
R.
R e n a u latn, d
for
R o b e r t saocr n
ek n o w l e d g e d
their
critical
r e v i e w so ft h em a n u s c r i p t O
. t h e rp e o p l eh a v ea s s i s t e dw i t h
thisproject
a r e a c k n o w l e d g e df o rt h e i r
a t v a r i o u st i m e sa n d
a s s i s t a n c eL: a r r H
y o l(t f i e l da' s s i s t a n t ) ,
( a s s i s t e dw i t h
L y nBnr a n d v o l d
s o m eo ft h ec h e m i c a la n a l y s e s ) G
, a r yM o r r i s
( e x c h a n g eo ff i e l da n dp e t r o g r a p h i cd a t aa n dd i s c u s s i o n so f
Dr.
tohcec u r r e tn
co
hacfere b o n a t i t e as n
) ,d
A.
J.
B u d d i(nagc c o m p a n itaehudetfhisen
oelrnvd e r a l
occasions).
Dr.
Clay
Smith
also
l e ntth ae u t h o r
maps a n d
a i r p h o t o so ft h ea r e a .
Iand d i t i o na ,p p r e c i a t i o n
is
e x t e n d et do
Dr.
Frank
husband,
James;
K o t t l o w s kfiohr i isn t e r e sat n sd u p p o rottfh i ps r o j e c t .
F i n a l l ya ,p p r e c i a t i o n
field
is
e x t e n d etdo
assistan
s at ,m pcloel l e c t oacrna,dm e r a m aTnh. i s
my
study was financed in part by
a grant from the New Mexico
Geological Society and by an assistantship from the New
Mexico
Bureau
o f Mines.
G e o l o g yo ft h eP r e c a m b r i a nR o c k so ft h eL e m i t a rM o u n t a i n s ,
S o c o r r oC o u n t y ,
New Mexico
INTRODUCTION
T h e L e m i t a r M o u n t a i n sa r el ' o c a t e da p p r o x i m a t e l ye l e v e n
km.
n o r t h w eS
os fot c o r r o ,
N e w M e x i c( foi g .
u n p a v e dr o a d sw e s to fL e m i t a r ,
1).
Several
New M e x i c o ,p r o v i d ee x c e l l e n t
two-
a c c e stt sohaer ebeayi t h e r
foor u r - w h e e l - d r i v e
v e h i c l ePs r. e c a m b r i ar o
nck
c rs oo p
au lt o nt hg
e ea s t e r n
f l a n k so ft h em o u n t a i n s .
T h e map a r e a( f i g .
limit
2 ) e x t e n d sf r o mt h es o u t h e r n
sec.
o fP r e c a m b r i a ne x p o s u r e( n e a rt h es e c t i o nl i n eb e t w e e n
1 8 a n d 1 9 , T.2S.,
in
sec.
32
R.lE.),
(T.lS.,
b o u n d a r i e s o f t h fe i e l d
n o r t h w a r dt ot h em i c r o w a v et o w e r
R.1E.).
a r eaar e
Tehaes t earnw
nde' s t e r n
f o r m ebtdy
heenodf
P r e c a m b r i a ne x p o s u r e .
T h e a r e a s o u t ho fC o r k s c r e wC a n y o n( l o c a t e da l o n gt h e
7 a n d 1 8 ) h abde epnr e v i o u s l y
s e c t i olni nbee t w e esne c .
mapped
by
Chamberlin
(1978
as
a n1d9 8 0ipn
,reparation)
P r e c a m b r i a nu n d i f f e r e n t i a t e dm e t a m o r p h i cr o c k s T
. h i sr e p o r t
d i v i d etsh seo u t h e r an r e ian t toh r e m
e a p p a b l lei t h o l o g i c
units
(Map
1 )C. h a m b e r l i (n1 9 7 a8 n 1
d 9 8 0i,p
nr e p a r a t i o n )
a l s or e c o g n i z e dd e f i c i e n c i e si nt h eg e o l o g i cm a p p i n g
of
the
LL
0
2
a
a
s
0
I
fn
>I-
z
3
0
0
0
K
K
0
0
0
v)
LL
0
n
Q
I
I
W
I
I
I
I
I
I
I
I
I
I
r
I
I
I
-.
I
,
Page 3
Woodward (1973) i n t h ea r e an o r t h
Precambrian
r o c k bs y
P r e c a m b r i a nr o c k s .
t o r e m a pt h e
it w a s n o th i si n t e n t i o n
C o r k s c r e wC a n y o n ,b u t
A s a p a r t of t h i sr e p o r t ,t h e
C o r k s c r e wC a n y o nn o r t h w a r d
of
area from
t ot h ei n t r u s i v ec o n t a c to ft h e
P o l v a d e r aG r a n i t eh a sb e e nr e m a p p e d
(Map 1).
W h e r e v e rp o s s i b l e t, h en a m e so fp a r t i c u l a rl i t h o l o g i c
u n i ht sa vbee eand o p t e d
or
t e r m i n o l ougsbyeyd
Woodward
m o d i f i ef d
r otm
hi ne f o r m a l
(1973).
e s p e c i a l lw
y i t thh ge r a n i t i rco c k s ,
many
cases,
new l i t h o l o g i u
cnits
informal,
w e r em a p p e db yt h ea u t h o ra n da s s i g n e d
names
In
descriptive
of
S e v e r .apl e r i o d s
P r e c a m b r i a nr o c k se x p o s e d
m e t a m o r p h i shm
a av fef e c t tehde
i n t h e L e m i t a r M o u n t a i n sa n dt h e
l i t h o l o g inca m essh o u lbdper e f i x ew
d i tthhtee r m
meta.
However,
the
currentrend
among P r e c a m b r i a ng e o l o g i s t s
is
leave
off
t ou s et h eo r i g i n a l i t h o l o g i cn o m e n c l a t u r ea n d
t h ep r e f i x
meta:
t h a ts t y l e
i s a d o p t e df o rt h i sr e p o r t .
PURPOSE
T h ep u r p o s eo ft h i sr e p o r t
i s t o d e s c r i b ea n dd e t e r m i n e
t h eg e o l o g i ch i s t o r yo ft h et h i c ks u c c e s s i o n
of P r e c a m b r i a n
s e d i m e n t sa n dg r a n i t i c ,m a f i c ,a n dc a r b o n a t i t er o c k se x p o s e d
in
t hLee m i t M
a ro u n t a i nTs h
. si tsu di ny c l u d d
e se t a i l e d
Page
4
m a p p i n g ,p e t r o g r a p h i cs t u d i e s ,a n dm a j o r -a n dm i n o r - e l e m e n t
“a
a n a l y s eosf
of s a m p l e D
s .e t a i l e d
r e p r e s e n t a t i v se u i t e
o n e i g h tc a r b o n a t i t es a m p l e s .
c h e m i c a ls t u d i e sa r ei n c l u d e d
From t h e result’s t h e f o l l o w i n g
w i l l b ed i s c u s s e d :
(1) t hsee d i m e n t a reyn v i r o n m e n t
.
(2)
t h se e d i m e npt r o v e n a n c e
(3)
t h en a t u r eo ft h em a f i ca n dg r a n i t i c
m a g m a t i s m a, n d
(4)
t h et e c t o n i cs e t t i n g .
METHOD OF INVESTIGATION
T h ea u t h o r ,a s s i s t e db yL a r r yB o l ta n dJ a m e s
McLemore,
area ( f i g .
s p e nat p p r o x i m a t e l y
fivm
e o n t hm
s apping
the
idne t a i l
at a
s c aol ef
1:6000.
7 . 5 - m i n u t eq u a d r a n g l e
map
a r e shown
on
r a d i o a c t i v i t yo ft h e
was
Lemitar
U.S.G.S.
was u s e d as a b a s e for g e o l o g i c
m a p p i n gA. r e aom
sf a j ooru t c r o p
s c i n t i l l a t i ocno u n t e r
The
the
map.
m a f i c a n dc a r b o n a t i t ed i k e sa n do t h e r
were s t a n d a r d i z e du, s i n g
t h er o c kc o l o rc h a r tb yG o d d a r d ,e t
al.
(1975).
One h u n d r e dt h i ns e c t i o n sw e r e x a m i n e dw i t h
p o l a r i z i n gm i c r o s c o p et od e t e r m i n el i t h o l o g i ca n d
Twenty
of
A
u s em
t ode a s u tr hn
e ea t u r a l
r o c kistnh fei e l dR. o c ck o l o r s
variations.
2)
the
thin
a
Zeiss
textural
s e c t i o nocsfa r b o n a t i t e s
Page
on
were
5
l o a nf r o mG a r r yM o r r i s ,a l s os t u d y i n gt h e s er o c k s .
.
Many o f t h e s l i d e s w e r e s t a i n e d t o a i d i n t h e i d e n t i f i c a t i o n
K
o -f f e l d s p aPrl.a g i o c l acsoe m p o s i t i ow
n sedr ee t e r m i n e d
1959).
u s i n gt h eM i c h e l - L e v ym e t h o d( K e r r ,
in
M i n e r ai dl e n t i f i c a t i o n s
c a r b o n a t i st ea m p l e s
d e t e r m i n e d from t h i ns e c t i o ns t u d ya n d
M i n e r a ls e p a r a t i o n s
byX-ray
were
diffraction.
were made w i t h a n a c e t i c a c i d l e a c h a n d
a h e a v ym i n e r a ls e p a r a t i o nt e c h n i q u eu s i n gt e t r a b r o m o - e t h a n e
( s p e c i gf ir ca v i t y
of
2 . a9
i dn6ed) n t i f i e d
X-ray
by
in
diffractA
i onna. l y t pi cr o
a lc e dduai rs ec su s s e d
a p p e n d i x A.
S e v e r a cl o m p u t e rp r o g r a m sw e r eu s e dt oc a l c u l a t e
and
MESO Norms ( K .
C.
CIPW
C o n d i ep,e r s o n aclo m m u n i c a t i o na)n d
o t h epre t r o l o g ipca r a m e t e r( sP e t c abB
ly i n g l e re ,t
1976).
T h ee d i t i n g
mode
e n a b l e dr a p i dr e v i s i o no f
RUNOFF
DEC20 a t New M e x i cToe c h
a s e m i - f o r m a t e dt h e s i st e x t ,w h i l e
( a f o r m a t e rp r o g r a i
toobtain
o tfh e
al.,
a c o m p l e t e dv e r s i o n
a t New M e x i c oT e c h )
of t h e t h e s i s t e x t .
was e m p l o y e d
6
Page
PREVIOUS WORK
of
T hPer e c a m b r i arno c k s
first
t hLe e m i t aM
r o u n t a i nws e r e
a n d Lasky
(1932).
b r i e f l yd e s c r i b e db yD a r t o n( 1 9 2 8 )
small
L a s(k1y9 3a2lms) eo n t i o n e d
f i s s u r e - f i l l io
n rge
of
d e p o s i at sl o nt g
hwee s t e rcno n t a c t s
of
e x p o s u r eTs h
.o ec c u r r e n c e
t hPer e c a m b r i a n
' u r a n i utim
h
nc ea l c a r e o u s
o f t h eL e m i t a r
b a s i cd i k e si n t r u d i n gt h eP r e c a m b r i a nr o c k s
M o u n t a i n s w a s f i r s t r e p o r t e d by S t r o u da n dC o l l i n s
(1954,
an
Adn d e r s o n
1957).
The
(1954)
f i r s t m i n i n g claims f o r
in
u r a n i u m ,f l u o r i t e ,a n ds u l p h i d e si nt h ea r e aw e r ef i l e d
1954 ( S o c o r r oC o u n t yC o u r t h o u s eR e c o r d s ) .
B o n n i c h(s1e9n6 2 )
made
a
g e n esrttahuoledf y
was
P r e c a m b r i a nr o c k si nt h eL e m i t a rM o u n t a i n sa n dt h ea r e a
(1973) a s p a r ot f
mapped
by
Woodward
the
Lemitar
a
m a p p i n gp r o j e c it n
(1979) d e s c r i b e
M o u n t a i n sC. o n d iaenB
dudding
of
t hlei t h o l o g ayn sdt r u c t u r ahl i s t o r y
Lemitar
r o c k si nt h e
Precambrian
r o c k isn
central
a n 1d 9 8 0 ,
i n
M o u n t a i n s as p a r t o f a ' s t u d y o f t h e
New M e x i c o ;
Chamberlin
p r e p a r a t i o nr)e m a p p e tdh L
e e m i t aM
r ountains,
i n c l u dr ei nc go n h a i s s amnacpe p i n g
exposures.
t hPer e c a m b r i a n
of
Ptrheec a m b r i a n
(1978
P a g e 7.
SEQIMENTARY
ROCKS
INTRODUCTION
A d e t a i l e dc o m p o s i t eP r e c a m b r i a ns t r a t i g r a p h i cs e c t i o n
L e m i t a r M o u n t a i n s i s d i f f i c u l tt od e t e r m i n eb e c a u s e
o ft h e
epxopooorfs uf ar eu sl ,ts ihnego
a,rtah
innedgr ,
d e f o r m a t i o nT
. hicknesses
may o n l yb eb r o a d l ye s t i m a t e dd u e
t o p o o r l ye x p o s e da n df a u l t e dp r i m a r yb e d d i n gs t r u c t u r e s .
A
i s shown i n
d i a g r a m m a t i cs k e t c ho ft h es t r a t i g r a p h i cs e c t i o n
3.
f'ig.
5%
P r e c a m b r i a ns e d i m e n t a r yr o c k sc o m p o s ea p p r o x i m a t e l y
o tf h eP r e c a m b r i a ne x p o s u r e( f i g .
2 ) a n dh a v ea e e nc a l l e d
1 9 7 3 ) . ' T h e yc a nb e
t h eC o r k s c r e wC a n y o ns e q u e n c e( W o o d w a r d ,
c l a s s i f i e d a s q u a r t z i t e s ( > 9 0 $ q u a r t z ) ,s u b a r k o s e s
(75
-
90%
( ( 7 5 % q u a r t zT) .hCeo r k s c r eC
wa n y o n
q u a r t z )a,nadr k o s e s
Lemitar
s e q u e n c ec o n t a i n tsh eo l d e srt o c k es x p o s e di nt h e
Mountains.
Two s t r a t i g r a p h i cu n i t sc a n
aL
nd
ower
Unit;
be d i s t i n g u i s h e d ,a nU p p e r
a nbdo u
t hn iht sa vb ee ei n t r u d ebdy
Unit
g r a n irtoi cTk
Lhso.ew e r
is
a
recrystallized,
Unit
f i n e - g r a i naerdk o as, n
etUh
,dpe p e r
c o n s i sotfs
r e c r y s t a l l iiznet d
e r, b e d
a rdkeod
s suebsa, r k oasneds ,
q u a r t z i t e s( f i g .
4).
S m a l l e n s e so fg r e e na n dg r a ys c h i s t
'
*
I
MUSCOVITE- BIOTITE GRANITE
INTRUSIVC
EONTACT
U P P E RU N I T
I N T E R B E D D E DA R K O S E S ,
SUBARKOSES, AND QUARTZITES
KEY
c]
ARKOSE
SUBARKOSE
0
QUARTZITE
M A F I CD I K E S
.._.. .
,.
G R A D A T I O N A LC O N T A C T
LOWER U N I T
M A S S I V EA R K O S E
I
l N T R u s l v E CONTACT
G N E I S S I CG R A N I T E
FIGURE
3 - D l A G R A M A T l CS T R A T I G R A P H I CS E C T I O N
OF T H E
PROTEROZO'ICCORKSCREWCANYONSEQUENCE,
L E M I T A RM O U N T A I N S
QUARTZ
&
QUARTZITE
SUBARKOSE
6
N U M B E R E DS A M P L E SW E R E
A L S OA N A L Y Z E D
FOR M A J O R
A N DM I N O RE L E M E N T S
(APPENDIX E ) ,
523
524f
ARKOSE
LlTHlCARENlTE
FELDSPAR
FRAGMENTS
F I G U R E 4-
C L A S S I F I C A T I O N O F S A N D S T O N E S FROM T H E CORKSCREWCANYONSEQUENCE
(MODIFIEDAFTERPETTIJOHN,
1957) BASED ON ESTIMATEDMODALANALYSIS
Page 1 0
is
a r e f o u n dl o c a l l yt h r o u g h o u t h es e q u e n c e T
. h es e q u e n c e
representativ
tohfefee l d s p a t h qi cu a r t z i at ena dr k o s e
a s s o c i a t i oenx p o s et d
hroughou
so
t u t h e ranncde n t r a l
New
1979).
M e x i c o( C o n d i ea n dB u d d i n g ,
F a i n tc r o s s b e d d i n ga n dg r a d e db e d d i n ga r ep r e s e r v e di n
a r k o s e sa n ds u b a r k o s e s
i n C o r k s c r e wC a n y o n ,i n d i c a t i n gt h a t
t h eC o r k s c r e wC a n y o ns e q u e n c ee x p o s e di nC o r k s c r e wC a n y o n
?
u p r i g h ty,o u n g i ntgo w a rtdh e
east.
A l t h o u gthh i n
c r o s s b e d s a r e common, t h e y a r e
is
laminar
n opth o t o g e n ibce c a u soef
p o oerx p o s u raenlda cok
cfo n t r a s F
t .o l i a t i opna r a l l e l s
relib
c te d d i n g
m, a k i nt g
hdei s t i n c t i obne t w e et n
h tew
, o
d i f f i c u l tF
. a i n ct r o s s b e d d i n ga n dg r a d e db e d d i n ga r eo f t e n
poorlp
y r e s e r v e idfnl o aat n idp
n o o r l ey x p o s e o
dutcrops
s o u t h o f C o r k s c r e wC a n y o n .
A c o n f o r m a b l eg, r a d a t i o n aclo n t a c t
Units,
t hUep p ae n
rLdo w e r
may
exist
a l t h o u gthhnea t u r e
between
of t h e
c o n t a c t i s d o u b t f u lb e c a u s eo fp o o re x p o s u r e sa n de a s t - w e s t
faults.
If
f o l i a t i o pn a r a l l e lrse l i cbt e d d i n tgh r o u g h o u t
t h ee n t i r es e d i m e n t a r ys e q u e n c e ,
e l s e w h e r e ,t h a nt h eL o w e r
a s i n C o r k s c r e wC a n y o na n d
U n i t i s o l d e rt h a nt h eU p p e rU n i t .
P a g e 11
DISTRIBUTION AND DESCRIPTION OF THE LOWER UNIT
U n i t c o n s i s t so f2 5 0t o3 0 0m e t e r s
TheLower
to
18.
of
arkose
s u b a r k o s ea n dc a nb ef o u n di nt h es o u t h e r nh a l fo fs e c .
may b eg r a d a t i o n a lw i t ht h eU p p e r
Unit
o ft h eC o r k s c r e wC a n y o ns e q u e n c ea n dt h es o u t h e r nc o n t a c t
is
ThL
e o w eU
r nit
i n t r u s i v ew i t ht h eg n e i s s i cg r a n i t e
cm.
d i k e( s2 - 1 5
(Map 1
)
:
t h i c ki)n t r u d teh e
S m a l lg n e i s s i c
L o w eUr n ai tl o ntgh e
s h a ri sn t r u s i vseo u t h e rcno n t a cwt h e rfeo l i a t i oitnnh e
i s prominent.
L o w eU
r n iatr k o s e
Also,
small i n c l u s i o n s o f
t h e Lower U n i t c a n b e f o u n d w i t h i n t h e g n e i s s i c g r a n i t e ,
consists
i s l o c a l l yf o l i a t e da n d
T hL
e o w e rU. n i t
of
a
a r k o s e t os u b a r k o s e O
. utcrops
d a r kg r a y v, e r yf i n e - g r a i n e d
a r e p o o ra n dg o o de x p o s u r e so c c u ro n l ya l o n gt h ei n t r u s i v e
c o n t a cw
t i t ht h eg r a n i t e .
I n t h i ns e c t i o n p, o o r l y
sorted,
r o u n d e dt os u b r o u n d e ds a n dg r a i n as r ep r e s e r v e da n do f t e n
a gr er a d e d .
A
s e r i c i t e ,3 5 - 4 0 % )
fine-grained
matrix
( p r o b a bql y
u a rat n
zd
i s p r e s e n t i nt h ea r k o s ea l o n gw i t hs a n d -
1,
untwinned
,
muscovite
IncontrasttotheinterbeddedandfoliatedUpperUnit,
the
Lower U n i t c o n s i s t so f
foliation
and
a m a s s i v ea r k o s ew i t ho n l yl o c a l
r e l ibcet d d i pn rge s e r v eQd u. a r t z iatne d
P a g e1 2
common i n t h eU p p e r
s u b a r k o s ei n t e r b e d s ,a l t h o u g h
n o tp r e s e n t
i n t h e Lower U n i t .
o tfh eL o w e r
q u a r t z i t efso u n d
Unit.
Unit, are
I n h a n d s p e c i m e n t, h ea r k o s e
U n i t i s s i m i l a r i n g e n e r a al p p e a r a n c et ot h e
i n t hoe v e r l y i n sge d i m e n tostfhU
e pper
i n t h i ns e c t i o nw h e r et h eL o w e r
T h eu n i t sd i f f e r
i s n o t a s w e l ls o r t e da n d
i s composed
of
a
Unit
l a r g e rq u a n t i t y
i n t h eU p p e r
o ff i n e - g r a i n e dm a t r i xt h a nt h ea r k o s e s
Unit.
DISTRIBUTION AND DESCRIPTION OF THE UPPER U N I T
Introduction
A p p r o x i m a to
tehnloy
eu s a
mniedntoet fer rs b e d d e d
a r k o s e sa n dq u a r t z i t e s
U n i t t o t h e south.
or
i n t h eU p p e r
U n i t o v e r l i et h e
Lower
is i n
fault
A m u s c o v i t e - b i o t i t eg r a n i t e
Unit
i n t r u s i vceo n t a cwt i tt hhUe p p e r
f o r m i n g a n e a r l vy e r t i c acl o n t a c t
i n sec.
on t hneo r t h
7.
p o oerx p o s u r et shnea t u rotefh icso n t a c t
B e c a u soef
is uncertain.
C h a m b e r l i n ( 1 9 7 8 ) m a p p e d ' t h i sc o n t a c t
as t h ee x t e n s i o no f
a
f a u lct u t t i n tgh K
e e l l e lyi m e s t o n eh; o w e v e rt ,h lea c ok f
s l i c k e n s l i d e s a n d b r e c c i a s is
c o n t a cr at t h et hr a n
i n c l ugssrcio
ahoy
fins st
m u s c o v i t e - b i ogtriatfan
ealivstoe r s
a
suggestive
of
an
intrusive
f a ucl ot n t a cTt .hoec c u r r e n coef
and
a r kwoist eh e
in
an
intrusive
Page 13
relationship
M. a f idci k e ps ,e g m a t i t e qs ,u a r tvze i n as n
, d
c a r b o n a t i t ed i k e sa l s oi n t r u d et h es e d i m e n t s .
in
A f a u lbt l o c k
o sf e d i m e n t cs r o p os u t
7.
p o r t i so enf c .
It
t h es o u t h e r n
i s b o u n dm
be ydu s c o v i t e - b i o t i t e
g r a nLti h
et em
e,d
i tiaorr i t e / g a b bP
arn
hod
a,n e r o z o i c
sediments.
th
l oi sc a l tsi hteyed i m e n
h tabsveee n
At
b r e c c i a t e da n dr e c e m e n t e d .
of
Tbheesxtp o s u r e s
Unit
tU
hp
eper
aar leo n g
C o r k s c r eCwa n y ownh, esreev e rhaul n d rm
e de t teohrfes
s e q u e nacerexep o s eSde. v e rParle c a m b r iaaT
nnd
ertiary
s o t h ee x a c tt h i c k n e s so ft h es e q u e n c e
f a u l t sc u tt h er o c k s ,
I n a d d i t i o n s, t r o n gd e f o r m a t i o n
i s d i f f i c u l t od e t e r m i n e .
in
a n sdh e a r i n g
thw
e estern
q u a r t e or tfh se e c t i o n
along
C o r k s cCraenw
oybol int e roartiegst ienxatalunr d
es
a n d d i k e l e t so g
f r a n i t i cp e g m a t i t e sa n d
s t r u c t u r e sL
. enses
a p l i taerse
common
in
small
tshhee a rr eodc ak ns ,d
l e n s - s h a p e db o u d i n a g es t r u c t u r e sa r ep r e s e r v e d .
Bedding
is
d i s t i n g u i s h a bb
cl o
y
e l coor n t r a sat ns d
t e x t u rvaal r i a t i o(nPsI .
compositions can
1
be
and
21,
bmuitn e r a l o g i c a l
d e t e r m i noe ndm
l yi c r o s c o p i c a l l y .
A
t e n - m e tbeheor o
df m o g e n e o um
s ,a s s i v
q eu a r t z ict ab
e ne
d i s t i n g u i s h e df r o mt h eo t h e rs e d i m e n t sb u t
C o r k s c r e wC a n y o n
(Map 1 ) .
a r ep o o ar n df e w
i n number.
i s s e e no n l y
O u t c r o p so u t s i d eC o r k s c r e wC a n y o n
Relicc
t r o s s b e d d i n ga n dg r a d e d
in
PL. 1:
T h i n l yl a m i n a t e di n t e r b e d d e da r k o s ea n dq u a r t z i t e
c u tb y
a n a p l i t ev e i n .
PL;
R e l i c t c r o s s b e d d i n gi na r k o s e .
2:
Page 1 5
can
bedding
b ed e t e c t e d
i n Corkscrew
Canyon
and elsewhere,
i s u p r i g h tA. r k o s e as r teh e
i n d i c a t i n tgh atth se e q u e n c e
m o s ta b u n d a n ts e d i m e n t f, o l l o w e db y( i no r d e ro fa b u n d a n c e )
s u b a r k o s em
s ,a f d
i ci k e qs ,u a r t z i t e as n
,gdr e eanngdr a y
schist.
Arkose
T haer k o s easr e
as
occur
common
throughou
t hts ee q u e n caen d
f i n ea-n m
d e d i u m - g r a i n e idn t e r b e d sF. o l i a t i o on f
is
tfhi en e - g r a i naerdk o s e
p r o d udcbaeyrdk - g raanyd
g r a y i s h - p i n lka y e r cs o n s i s t i n o
gpf o o r l sy o r t e sd a n da- n d
s i l t - s i zger a i n s
biotite
of
q u a r(t2z5 - 3 0 %f )e,l d s p(a1r5 - 2 5 % ) ,
muscovite (5-15%), and a trace
a m o u not f
(10-20%),
h o r n b l e n d ae n m
d a g n e t i t (ef i g .
may
bpe r e s e n t
4).
Up t o 1 5
-
20%
matrix
i n t hfei n e - g r a i n eadr k o s e sC. r o s s b e d d i n g
a n d g r a d ebde d d i nagroef t epnr e s e r v eadl o nw
g i t.ht h i n
l a y e r s o f c o a r s ea r k o s i c
or s u b a r k o s i c s a n d ( p l .
3 and 4).
M e d i u m - g r a i n eadr k o s ed si f f ferrotm
hf ien e - g r a i n e d
a r k o s e sb yh a v i n g
l i t t l e o rn om a t r i x
a n d l a r g e ar n dm o r e
r o u n d e ds a n dg r a i n s .F o l i a t i o no ft h em e d i u m - g r a i n e da r k o s e
is
s i m i l a r tfh
tion
e e - g r a i naerdk o sMe e. d i u m - g r a i n e d
a r k o s ec so n s i os atf n d - s i zger a i n s
K-feldspar
(5-15%),
of
q u a r (t 5z 0 - 7 0 % ) ,
p l a g i o c l a s e , A n 1 0 - 4(01 5 - 3 0 % )b,i o t i t e
(10-20%), m u s c o v i t e( 2 - 5 % ) a, n dm i n o ra m o u n t so fm a g n e t i t e .
PL. 3:
P h o t o m i c r o g r a p h ( 2 5 x , cross-polars) showing graded
bedding in arkose.
PL. 4:
Fine-grained'arkose, showing crossbedding.
P a g e 17
T hi en t e r b e d d eadnfdo l i a t eadr k o s eotsh
fUe p p eUr n i t
d i f f e r sf r o mt h e
U n i t b yh a v i n g
massive a r k o s eo ft h eL o w e r
of
q u a r t z iat n
se ud b a r k o isnet e r b e ad n
tsp
hdre e s e n c e
K-feldspar.
Subarkose
T h es u b a r k o s e sa r ed i s t i n g u i s h a b l ef r o mt h ei n t e r b e d d e d
a r k o s e sb yt h e i rh i g h e rq u a r t zc o n t e n t( 7 5 - 9 0 %q u a r t z ) .T h e
r o c k sa r ef o l i a t e dw i t hd a r k - g r a ya n dg r a y i s h - p i n kl a y e r s ,
similar t oa r k o s e s ;t h e yo c c u r
as t h i ni n t e r b e d s
(less than
s e v e r a lm e t e r st h i c k )s c a t t e r e dt h r o u g h o u tt h es e q u e n c e -I n
f i n e - t o medium-sand
t h i ns e c t i o n r, o u n d e da n dw e l l - s o r t e d
(70-80$),
g r a i nc so n s i o
qs fu
t artz
( p r o b a b lm
y icrocline,
amounts
Of
5-15$),
p e r t h i tK
i c- f e l d s p a r
b i o t i t(e1 0 - 1 5 % )a,nm
d inor
matrix
plagioclasm
e ,u s c o i r i t m
e , a g n e t i t ae n
, d
r
4 and pl.
(fig.
5).
Quartzite
qTuha er t z i t e s
are
m a s spi ivneg
tk,ori as h
y
m e d i u m - g r a ya,nvde rfyi n e d - g r a i n e dT. h ilna m i n abre d d i n g
i s o f t e np r e s e r v e da l o n gw i t h
w e l l r o u n d e d ,w e l l - s o r t e d ,a n d
( > g o % ) w i tmh i n o r
f i n e - s a ngdr a i n sc,o n s i s t i nogqfu a r t z
amounts
.~
probably
opf e r t h i t i K
c -feldspar
matrix
p l a g i o c lma u
s es c
, om
v iat g
e ,n eat n
i tde ,
photomicrograp
f ihg, .
-microcl-ine),
8,
p.
11,
Woodward,
1973).
(see
The
PL. 5:
Photomicrograph ( 2 5 x , cross-polars) o f a subarkose.
19
Page
as
q u a r t z i toecsc u r
. cm.
t hbien(ds se v e r a l
thick)
i n t e r b e d d e dw i t ha r k o s e sa n ds u b a r k o s e s .
Schist
S c h i s lt e n s e so c c u sr c a t t e r e dt h r o u g h o u t h es e d i m e n t
as
s e q u e n caen d
i n c l u s i o nw
s ithin
v a r i o u gs r a n i t i rc o c k s .
T hoer i g i n ar ol c k s
may
Most
lenses.
tgheeo l o g i c
h a vbee emn a f d
i ci k eos sh
r ale
small t ob e
o ft h e s el e n s e sa r et o o
map
w tieh
txhec e p t ioofn
some
larger
(Map 1, sec.
i n c l u s i o n sf o u n dw i t h i nt h eg r a n i t i cr o c k s
. T h es c h i s t s
shown
on
7).
a r e s t r o n g l yf o l i a t e d ,g r a y i s ho l i v eg r e e n ,
f i n e - g r a i n e d. ,m i c a e o urso c kas n cd o n s i sotcf h l o r i t ae n d
biotite
(40-50%),
( 5 - 1 0 % a) ,n d
plagioclase,
magnetite
An40-50
(30-35%),
quartz
( 5 - 1 0 5 )T. hceh l o r i taenbdi o t i t e
c o n t e n t may r a n g e as h i g h as 9 0 5 , w i t hc h l o r i t eo f t e nm o r e
a b u n d a n tt h a nb i o t i t e .
as
G r as yc h i lset n s eo sc c u r
i n c l u s i o nwsi t h it n
he
m u s c o v i t e - b i o t gi tr ea n aiwtneidt hs ienv e ir saol l a t e d
i n sec.
o u t c r o p so fP r e c a m b r i a nr o c k s
composed
of t h i n( s e v e r a l
cm.
~
7 (Map 1 ) ; t h e ya r e
t h i c k )a l t e r n a t i n gl a y e r so f
m a s s i vqeu a r t p
z ,l a g i o c l a s b
e ,i o t i t ae n
, md u s c o v i t T
e .h e
g r a ys c h i s ot f t e ng r a d e si n t o
o f t eonc c u r s
a thinlb
yeddea
d r k o s ae n d
as i n c l u s i o nw
s i t h i tnh ce a r b o n a t i t de i k e s .
T h e s eg r e e nc h l o r i t ea n dg r a ys c h i s tl e n s e s
a r e s e l d o mm o r e
P a g e2 0
we t e lros nagnadr e
t h a n a f em
common
a l o nsge c o n d a r y
7 a n d1 2 .
arroyos i n sec.
GEOCHEMISTRY
A r e p r e s e n t a t i v se u i t oesf a m p l e fsr o m
t hC
e orkscrew
was a n a l y z e d f o r e i g h t m a j o r a n d f o u r t r a c e
C a n y o ns e d i m e n t s
e l e m e n t (sA p p e n d i x
fig.
2.
B).
T h es a m p l el q c a t i o n sa r ep l o t t e do n
c oI nm p a r i swao
t ih
vnt eh r af egled s p a t h i c
q u a r t z i t e - a r k o s ef r o mt h eP r e c a m b r i a no sf o u t h - c e n t r a l
1979),
M e x( iCcoonB
adnuide d i n g ,
A1203,
Fe203,
a n d B a ( t a b l e 1).
MgO, N a 2 0S, rR, b ,
401) i s h i g h e r i n S i 0 2 F
, e203,
a n d Sr a n dl o w e r
i n K20, T i 0 2 a, n d
MgO, C a O ,
A1203
r o c k sf o rt h e
Na20,
Ba,
Rb,
t h a nt h ea v e r a g e
in
P r e c a m b r i faenl d s p a t hqi u
cartzite-arkose
T h e s ed i f f e r e n c e s
The
U n i t o ft h eC o r k s c r e wC a n y o ns e q u e n c e
a r k o s ef r o mt h eL o w e r
(Lem
and
at hr k
eoses
U n i t a r el o w e ri nS i 0 2 ,a n dh i g h e r
s u b a r k o s e so ft h eU p p e r
in
New
New
Mexico.
may r e p r e s e n tt h eh e t e r o g e n e i t yo fs o u r c e
New M e x i c oP r e c a m b r i a nf e l d s p a t h i cs e d i m e n t s .
T hLe e m i t asre d i m e n tcsabnceo m p a r etdaoanv e r a g e
graywacke
and
a r k o s(et a b l e
s e d i m e n tasrhei g h e r
in
2 a nfdi g .
Na20
an
,d
K20
5).
t h atnhaev e r a g e
g r a y w a c k ea n da r k o s e .G e n e r a l l y ,t h eL e m i t a rs e d i m e n t s
i n t h ea r k o s ef i e l d( f i g .
5).
T hLee m i t a r
fall
Page 21
TABLE 1
GEOCHEMISTRY OF SANDSTONES
1
4
3
5
77.1
66.1
0.3
66.7
0.6
77.8
0.54
65.6
0.3
8.7
8.1
13.5
11.1
2.28
5.4
2.4
5.5
4.57
2.1
2.5
2.9
0.94
16.8
6.67
1.49
K20/Na20 1.8
Si02/A1203 6.0
1.9
0.9
-
113
52
530
0.5
2.7
1.5
2.8
6.2
0.9
1.3
95.88 90.7
1.4
8.2
,
1.39
2.45
2.6
2.9i
95.8 101.70
0.7
4.9
I
6
Si02
77.5
Ti02
0.63
A1203 12.8
Fe203* 2.71
MgO
0.34
CaO
0.96
Na20
1.71
3.14
K20
TOTAL 99.79
Rb
Sr
Ba
*
2
0.73
75.2
0.62
13.2
4.74
1.20
2.02
2.37
2.70
4.71
3.00
99.14.102.68
0.77
2.0
3.9
1.1
7.0
139
223
78
156
1189
202
162
1.2
1172
5.7
1186
Total iron expressed as Fe203.
average feldspathic quartzite-arkose from
the
Precambrian o f New Mexico (Condie and
Budding, 1979)
2 - average arkose (Pettijohn, 1963)
3 - average lithic arenite (Pettijohn, 1963)
4 - average graywacke (Pettijohn, 1963)
5 - arkose, Lower Unit, Lemitar Mountains (1 sample)
6 - average arkose, Upper Unit, LemitarMountains
(average of 3 analyses)
7 - average subarkose, Upper Unit, Lemitar
Mountains
(average o f 2 analyses)
1
e
2.8
523
2.6
e @
a
GRAYWACKE
2.4
520 524
A
8
40 I
FIELD
Na20
- AVERAGE
- AVERAGE
GRAYWACKE
ARKOSE
ARKOSE
FIELD
2.2
2.0
I .8
a
3
4
5
6
K20
FIGURE 5 - Na20 - K20
PLOT OF SANDSTONES FROM THE
CORKSCREW CANYON
SEQUENCE (DIAGRAM AFTER PETTIJOHN, 1963)
0.5
GRAYWACKE
C
Na20
K2°
QUARTZITE
'E
ARENITE
- 0.5
-I
0.5
2c.5
1
LOG
7
2.5
1.5
5102
A1203
FIGURE 6 -GEOCHEMICALCLASSIFICATIONOFSANDSTONESFROMTHE
CANYON SEQUENCE(AFTERPETTIJOHN,
1963)
CORKSCREW
Page 23
TABLE 2
CHEMICAL CLASSIFICATION OF SANDSTONES
( m o d i f i e df r o mP e t t i j o h n ,P o t t e r ,a n dS i e v e r ,1 9 7 3 )
HIGH Si02/A1203 RATIO
-
Q u a r t za r e n i t e s( q u a r t z i t e s )
mature, l i t t l e c l a y o r d e t r i t a l Al-silicate
(1)
a l k a lrii c (hc a r b o n a t ce e m e n t )
( 2 a) l k a l i
( s i l i c a cement)
poor
LOW S i 0 2 / A 1 2 0 3 R A T I O ( ( 1 2 )
immature, c l a y p l u s d e t r i t a l A l - s i l i c a t e
(1)
a l k a l ri i c h
(a)
iVa20>K20
(b)
Na20<K20
( 2 )a l k a l ip o o r
NOTE
-
-
-
f e l d s p a t h i cg r a y w a c k e s
a r k o s e s ,l i t h i cg r a y w a c k e s
l i t h i ca r e n i t e s
g r a y w a c k e is d e f i n e d a s a s a n d s t o n e h a v i n g
matrix.
>15%
Page 24
\
A c h e m i c a cl l a s s i f i c a t i o n b, a s e d
on
t h ec o m p o s i t i o n a l
m a t u r i to
ytfh .es e d i m e n th, abs e e p
nr o p o s e d
(1963 a n dP e t t i j o h n P
, otter,
6).
afni dg .
by P e t t i j o h n
1973;
and Siever,
s e et a b l e
2
f a l l tlihonew
TLheem ist ea dr i m e n t s
S i 0 2 / A 1 2 0 3g r o u pa n dn e a tr h eb o r d e b
r e t w e e nt h eh i g ha n d
i s c h a r a c t e r i s t ioc f
l o awl k a sl iu b g r o u p sT. h igsr o u p i n g
y o u n g e ra r k o s e s
and lithicarenites.
One m u s tu s ec a u t i o n
when u s i n gt h e s ed i a g r a m sb e c a u s e
t haef f e cortfe g i o n aml e t a m o r p h i s o
m
sne d i m e n t s
i s not
(1966)
c l e a rul y
n d e r s t o oSdc. h w a r c z
s t u d i ea d
n
ro
e af
r e g i o n a lm e t a m o r p h o s e da r k o s i cq u a r t z i t e sa n df o u n dt h a tn o
a p p r e c i a b lceh a n g e
i n modal
or
m a j oerl e m e nc to m p o s i t i o n
Shaw ( 1 9 5 4 ,
i n m e t a m o r p h igcr a d e .
o c c u r r ew
d i tihn c r e a s e
1 9 5 6 1 , B a r t h( 1 9 3 6 ) a, n d
Mason ( 1 9 6 2 a) l s of o u n da l m o snt o
s i g n i f i c a n tc o m p o s i t i o n a lc h a n g e si ns e d i m e n t sm e t a m o r p h o s e d
u tptoh ue p p ear m p h i b o l i t fea c i e s .
It
is
p r o b a b lteh a t
m e t a m o r p h i s mh a sn o ts i g n i f i c a n t l yc h a n g e dt h em a j o re l e m e n t
c h e m i s t r yo ft h eL e m i t a rs e d i m e n t sb e c a u s et h e i rc h e m i s t r i e s
a r en o ts i g n i f i c a n t l yd i f f e r e n tf r o mc h e m i s t r i e so fy o u n g e r
1963),
a rskuaobnsadersk(oPseetst i j o h n ,
m e t a m o r p h i ca f f e c t s
may a c c o u n t f o r s o m eo ft h ed i f f e r e n c e s
th
ex
abti es t w etLehenem i st ea d
r i m e anr ntesdc e n t
sediments.
although
Page25
PROVENANCE AND SEDIMENTATION
Some
c o on rstithgrseaio
enid
nnai tlms e n t a r y
c a n dbeed u cf er od m
e n v i r o n m eantnetdc t o ns iect t i n g
m i n e r a l o g ti ec x
a glt ,uae rn
oad
clh, e mviacrai la t i o n s .
i s c o n t r o l l e d by a number o f f a c t o r s
S a n d s t o n ec o m p o s i t i o n
(Potter, 1978):
(1) c o m p o s i t i o n a n d v o l u m eo ft h es o u r c e
(2)
relief
(3)
weathering
(4)
climate
(5)
m e t h o da n dd i s t a n c eo ft r a n s p o r t .
T h ea b u n d a n c eo fq u a r t za n df e l d s p a ri n d i c a t e s
a source
acr oe n
a s i sgtroi ag
nf nn
goiert ies s .
By
applying
19791,
D i c k i n s o n ' cs r i t e r i a( 1 9 7 0D
, i c k i n s o na n dS u c z e k ,
a
i s i n d i c a t e fdotrh L
e emitar
g n e i s s io
c gr r a n i t i sc o u r c e
M o u n t a i nbstyhhei gqhu a n t i t i eoqsfu a r taznfde l d s p a r
( > 2 5 % )a n dt h e
7).
low q u a n t i t i e s of l i t h i cf r a g m e n t s
(O%,
fig.
R o u n d e d st ou b r o u n d et ed x t u r es u
s g g e isnt t e r m e d i a t e
t r a n s p o rdt i s t a n c e s ,
f r o mt h er e w o r k i n g
if
t h e stee x t u r easrne oi tn h e r i t e d
o f a q u a r t zs a n d s t o n e
T h er e l a t i v ea b u n d a n c eo ff e l d s p a r
i n d i c a t i v eo f
i n t h es o u r c ea r e a .
i n t h es e d i m e n t s
is
a n e n v i r o n m e n t i n w h i c hi n t e n s ew e a t h e r i n gd i d
n oetx i s S
t .u cshe d i m e n t s
may h a vf o
e rmed
in
a
variable
Q
F LQ
CONTINENTALBLOCKPROVENANCE
CRATONINTERIOR
C O N T I N E N T A LR I F T
T O T A LQ U A R T Z O S EG R A I N S
RECYCLED OROGEN PROVENANCE
SUBDUCTION COMPLEX
COLLISIONOROGEN
FORELANDUPLIFT
T O T A LF E L D S P A RG R A I N S
TOTALLITHICGRAINS
MAGMATIC ARC PROVENANCE
UNDISSECTED ARC
DISSECTED ARC
PROVENANCE
MAGMATICARC
PROVENANCE
25
L
F
FIGURE 7 - T E C T O N I C
PROVENANCEOFPROTEROZOICSANDSTONES
(DIAGRAM PROPOSED BY DICK I NSON ANDSUCZEK, 1979)
L
FROMTHELEMITAR
MOUNTAINS
c l i m a t ei nw h i c he r o s i o na n db u r i a w
l e r er e l a t i v e l yr a p i d
(Folk, 1974;
P o t t e r , 1978;
Condie a n d Budding, 1 9 7 9 ) .
may r e f l e c t a l o c a l
m a s s i v eq u a r t z i t eb e d si nt h es u c c e s s i o n
t e c t o n i c a sl lt y
a bs o
l eul roccr ea l i zr ee dw o r k i n g
q u a r t z o - f e l d s p a t h i cs e d i m e n t s
The
of
i n a high
energy
environment
( s u c h as ainn t e r t i d az lo n e T
) .hseu b r o u n d esdh a p easn d
small
stqio
hzufeea g
r trza if na svr oe rw o r k ionfg
q u a r t z o - f e l d s p a t h i cs e d i m e n t s .
T h em i n e r a l o g i c a la n dt e x t u r a le v i d e n c ea r ec o n s i s t e n t
w i t hd e p o s i t i o n
a nSd i n g h ,
i n a f l u v i a l or d e l t a i ce n v i r o n m e n t( R e i n e c k
1973).
H o w e v e rt ,heev i d e n c e
t od i f f e r e n t i a t eb e t w e e n
n o st u f f i c i e n t
is
a l a c u s t r i n e or a m a r i n es e t t i n g .
T h eR
. inconadF
a ormation
(Precambrian)
in
and
M e x iccoon s i o
sn tft se r b e d dqeuda r t z i t e s
s c h i s t s similar t o
thC
e orkscrew
a n dK i r s c h n e r ,
1979).
northern
New
pelitic
C a n y oSn e q u e n c(eB a r r e t t
T h e s ed e p o s i t h
s a v eb e e ni n t e r p r e t e d
t o r e p r e s e n dt e l t a i c f, l u v i a l ,
and
s h a l l o w - m a r i n de e p o s i t s
b a s eodtnhper e s e n coecfr o s s b e d d i n gr ,i p p l e
marks,
and
g r a d e db e d d i n ga n do nt h es i m i l a r i t yb e t w e e nt h eR i n c o n a d a
s e d i m e n tasnH
d o l o c e nsee d i m e n tfsr o m
t hDe o n j e cRk i v e r ,
Yukon ( f l u v i adl e p o s i t s )a, n d
N i g e dr e l t a
syst,ems
a nK
dirschner,
1979).
T hCeo r k s c r eC
wa n y osne d i m e n t s
r e p r e s e n t a s i m i l a r d e p o s i t i o n a le n v i r o n m e n tb e c a u s eo f
s i m i l a r i t yi np r i m a r yb e d d i n gs t r u c t u r e sa n dl i t h o l o g y .
(Barrett
may
the
Page 28
S e v e r a la t t e m p t sh a v eb e e n
made t oa p p l ym i n e r a l o g i c a l
c o m p o s i t i op
to
nl a t e - t e c t o n si ce t t i n g( D
s i c k i n s o1
n9
, 70;
Dickinson a n d Suczek, 1979;
Dickinson and
V a l l o n i1, 9 8 0 ) .
7 ) clearly
Td
ho
e m i n a nfocefel d s paan
qr d
u a r(tfzi g .
i n t h eL e m i t a rM o u n t a i n s
i n d i c a t e st h a tt h es e d i m e n t sf o u n d
i n a c o n t i n e n t a bl l o c kp r o v e n a n c e a, s s u m i n g
w e r ed e p o s i t e d
i s a p p l i c a b l tetoh L
e e m i t aM
r ountain
D i c k i n s o n 'tsh e o r y
P r e c a m b r i asne d i m e n t s .
Two s p e c i f i tce c t o n i sc e t t i n g as r e
( 1 9 7 9 ) a so c c u r r i n gi n
r e c o g n i z e d b yD i c k i n s o na n dS u c z e k
-
c o n t i n e n t a lb l o c kp r o v e n a n c e
u p l i f t e d, b a s e m e n t
a
t h ec r a t o ni n t e r i o ra n dt h e
(rift zone).
C h e m i s thbray
eu
sedsn
tieofdf e r e n t i abteet w e e n
1975).
a n c iteenctt osnei tct i n
( Sg cs h w a b ,
s a n d s t o n(ecsh a r a c t e r i s toi fc
rift
and
valleys
rising,
a h i g hS i 0 2c o n t e n ta n d
s t a b l ec o n t i n e n t a l -m a r g i n s )h a v e
K20/Na2O r a t i oe q u a tl o
Quartz-rich
a
o r g r e a t etrh a on n eT. hL
eemitar
s a m p l e s ,w i t ho n ee x c e p t i o n ,
f i t t h e s ec r i t e r i a( t a b l e
3).
B l o c kf a u l t i n ga s s o c i a t e dw i t hr i f t i n gc o u l du p l i f t
g r a n i t ibca s e m e n at ;nrda p iedr o s i oanl o nsgt e espl o p e s
c o u l dp r o d u c ea l l u v i a l - f a nd e p o s i t s ,r e s u l t i n g
and
i n t h eg r a d e d
c r o s s b e d d e dp ,o o r ltm
yo o d e r a t e lsyo r t efde l d s p a t h i c
s e d i m e n tssu c h
as t h o se x p o s e d
in
t hL
e e m i t aM
r ountains.
P r o l o n g e da b r a s i o no af n yq u a r t z - r i c hs o u r c ec o u l dp r o d u c e
quartzitesD
. e l t a i ce n v i r o n m e n t sc o u l dd e v e l o pf u r t h e rf r o m
a
P a g e 29
TABLE 3
GEOCHEMISTRY OF THE LEMITAR SEDIMENTS
76.5
69.6
62.0
77.8
73.8
S i 0 2 / A 1 2 0 3 3.8
6.2
4.8
3.3
7.0
5.3
K ~ O / N ~ ~ 1.6
O
0.8
1.6
3.2
1.2
1.5
S6 i50. 2
P a g e 30
theupliftedterrain.
more
A
envisioned
t e c t o n i c a sl lt y
a be lnev i r o n m ec no tubled
as
well,
(Schwab,
1975) or
1979).
A
s u cahs
a r i s i ncgo n t i n e n t a l - m a r g i n
a c r a t o ni n t e r i o (r D i c k i n s o na n dS u c z e k ,
g r a n i t i cs o u r c ec o u l de x i s t
c o n d i t i o n sf o r
a l o n gt i m e ;a n d ,u n d e rd r y
a t r e l a t i v e l ys t a b l e
or c o l dc l i m a t i c
Over a
c o n d i t i o ntfhse,el d s p awr o
s undlodetc o m p o s e .
l e n g t h o f t i m et,h ae b r a s i v ae c t i o n
produced
wind
may
c o u l pd r o d u caer k o s isca n d(sF o l k ,
dbeer i vfer d
o
l omc a rl el yw o r kseedd i m e n t
i n t e r t i d azl o n eF. l u v i aol dr e l t a i ec n v i r o n m e n t s
c o n s i s t e n tw i t hs u c h
a setting.
by
1974).
water
or
Quartzites
in
wou.ld
be
an
Page 31
IGNEOUS
ROCKS
INTRODUCTION
T h eP r e c a m b r i a ni g n e o u sr o c k s
i n t h eL e m i t a rM o u n t a i n s
a m a f i ci n t r u s i v eb o d y( L e m i t a rd i o r i t e / g a b b r o ) ,
c o n s i s to f
a g r a n i t i cc o m p l e x m
, a f i cd i k e s a, n dc a r b o n a t i t ed i k e sa n d
a
a gr er o u p ea dc c o r d i nt og
c l a s s i f i c a t i omno d i f i eb dy
(1967,
Hyndman ( 1 9 7a2f )tSet rr e c k e i s e n
8).
fig.
The
i g n e o u sr o c k sh a v eb e e nm e t a m o r p h o s e da n ds h o u l db ep r e f i x e d
w i t ht h et e r mm e t a ,b u tf o rt h ep u r p o s e so ft h i sr e p o r tt h e
o r i g i n a ln o m e n c l a t u r e
Lemitar
P r e c a m b r i agnr a n i t irco c kistnh e
compose
meta.
is u s e d , l e a v i n g o f f t h e t e r m
Mountains
7 5 % o f t h et o t a le x p o s e dP r e c a m b r i a nt e r r a i n ,w h i l e
t h e L e m i t a r d i o r i t e / g a b b r oc o m p o s e
2 0 % o ft h et o t a le x p o s e d
N e w M e x i c oP,r e c a m b r i agnr a n i t i c
P r e c a m b r i atne r r a i nI .n
r o cckosm p oaspep r o x i m a t etlw
tyhoi rto
eh
dx
fes p o s e d
1979)
P r e c a m b r i taenr r a(iC
n o n dai n
B
e du d d i n g ,
as w e l l ( D e n i s o n a n d
m a j o r i t yo ft h eb a s e m e n t
1969;
al.,
M u e h l b e r g eer t,
n o t a s common,
Mexico.
A
1966).
a nt hde
Hetherington,
M a fri oc c kasl,t h o u g h
a r ep r e s e n tt h r o u g h o u tt h eP r e c a m b r i a ni n
1 . 5 - b . (yW
. hite,
1 9 7 8 ) g a b b rcor o posu t
New
i n the
M a g dM
a loeunna( tLaK
oi n
uoasgnchdhl1im
9n4a 2n ;,
Blakestad,
1976;
S u m n e r1, 9 8 0t)h a t
may b er e l a t e dt ot h e
X GNEISSIC
GRANITE
0
POLVADERA
GRANITE
+
M U S C O V I T E - B I O T I TGER A N I T E
A
B I O T I TGER A N I T E
CB
MAFIC
DIKES
QUARTZ
0 DlORITE/GABBRO
DIKE
+
OIAEASE
TRONOHJEMITE
QUARTZ-BEARING
GRANODIORITE
QUARTZ-MONZOGABBRO
MONZONITE
NORITE,
DIORITE,
MONZONITE
ALKALI
'ELDSPAR
FIGURE 8 -
10
,
35
GABBRO
65
90
PLAGIOCLASE
CLASSIFICATIONOF
SAMPLESFROMTH
IGNEOUSROCKS(AFTER
STRECKEISEN, I967 AND HYNDMAN, 1972) SHOWING
E LEMITAR MOUNTAINS BASED ON ESTIMATEDMODALANALYSIS
P.age 33
L e m i t a rd i o r i t e l g a b b r o .
1978;
R e c e ngte o c h r o n o l o g isct u d i e(sW h i t e ,
et
al.,
1978;
1979) o tf h eP r e c a m b r i a n
Condie a n d Budding,
r o c k isn
c e n t r aal n d
southern
New
Brookins,
most
M e x i ciom p ltyh a t
1 . 5 a n d 1.1 b . yT. h e s e
g r a n i t i cp l u t o n i s mo c c u r r e db e t w e e n
s t u d i e ss u g g e s tt h a tp e r h a p st h eP r e c a m b r i a ng r a n i t i cr o c k s
i n t h eL e m i t a rM o u n t a i n sw e r ee m p l a c e dd u r i n gt h i sp e r i o d .
LEMITAR D I O R I T E / G A B B R O
Introduction
The Lemitar
out
d i o r i t e l g a b b rc or o p s
C o r k s c r eC
wa n y osne d i m e n (t sf i g .
2),
n o r tohf e
f o r m i n g many o f t h e
l o w ehr i l l as n rdi d g e as l o n tgh ee a s t e r p
no r t i oo
ntfh e
mapped
area.
a s f a u l bt l o c k s
T h de i o r i t e l g a b b r co o n t i n u e s
a n dw i n d o w sf a r t h e rn o r t ho ft h e
mapped a r e a .
forms
T shoe u t h ebr n
o u n d atorb
hy
fo
edy
a
nearly
v e r t i c a ol ,f t em
n i g m i t i z e di n, t r u s i vceo n t a c w
t , h e rt eh e
d i o r i t e l g a b b r o i s i nc o n t a c tw i t hm u s c o v i t e - b i o t i t eg r a n i t e .
T hw
e e s t e rb
no u n d a r y
i s f o r m e bduy n c o n f o r m a b l oy v e r l y i n g
bP
eod
hfsa n e r o z os iecd i m e nT
t esha. es t ecronn t a c t
formed
by
a
series
P h a n e r o z o i cs e d i m e n t s
of
f a u lat n
u
sd
n c o n f o r m i t iw
e si t h
and volcanics.
is
P a g e 34
of t hneo r t h w e s t e rcno n t a c t
T hnea t u r e
in
is
doubt
b e c a utlohsagfeocofkeoxdp o s u r eTsPh. oe l v a d e r a
G r a n i t e i s i n f a u l t or i n t r u s i v ec o n t a c w
t i t ht h e
diorite/gabbro
on
a northeast-striking
t h ne o r t hf,o r m i n g
and
c o n t a c tE. v i d e n c eosbfr e c c i a t i o n
Lemitar
s l i c k e n s l i d eos c c u r
a l o np gatorhnft eo r t h e a settoa- s t - t r e n d i nc go n t a c t
and
b e t w e e tnhde i o r i t e / g a b b r o
indicate
as
3 2 , Map 1).
f a u cl to n t a c
( st e c .
a
c o u l d form t h e r e m a i n d e r of
units
t hPe o l v a d e rG
a r a n i taen d
(1978)
Chamberlin
T h fi sa u l t
t hceo n t a cbt e t w e e tnhtew o
mapped
b r e c c i a t i oannsdl i c k e n s l i d easr e
it,
more
bu
t htl e
a cokf
s u g g e s t i voef
an
i n t r u s icvoen t a cNt e.tcaho
ren t af cotl i a t it io
hnn
e
diorite/gabbro
t hP eo l v a d e G
r ar a n i pt ea r a l l etlhs e
and
c o n t a c ts u g g e s t i n g
a n i n t r u s i v er e l a t i o n s h i p .
Th
mea fbi c
ody
is
intruded
by
b i o t i tger a n i taen d
l e u c o g r a n i t ed i k e sa n dp l u g s ,a n dp o r t i o n so fp e g m a t i t e sa n d
q u a rvt ze i anfrsoe u ns cd a t t e r et hdr o u g h o uM
t .a fai n
cd
c a r b o n a t i dt ei k ae ls si no t r u dt hd
e ei o r i t e / g a b b r o .
m a f idci k e s
may b e
a
l a tset a goet fhdei o r i t e / g a b b r o ;
o t h e r si n t r u d et h i sg r a n i t ea n da r ep o s t - g r a n i t e .
Some
P a g e 35
Description
Td
h ieo r i t e j g a b bm
r oa i n t a i n s
a
mm.
p r o dluab(crsyegedev e r a l
phenocrysts
of
plagioclase.
It
s p e c k laepdp e a r a n c e
i n
d i a m ew
t ehr i)t e
a
is
lithologically
h e t e r o g e n e o u su n i tr a n g i n gf r o mg a b b r oa n dd i o r i t et oq u a r t z
4).
g a b b raonqdu a r tdzi o r i t( et a b l e
varies
i n m i n e r a l o g i c a lc o m p o s i t i o n ,b u tp r i m a r i l yc o n s i s t s
o f p l a g i o c l a s e , An40-60
hornblende (30-40%),
10-20%),
T hdei o r i t e j g a b b r o
(30-40%),
and
d a r kb l u e - g r e e n
brown
b i o t i t e( p a r t i a l l ya l t e r e dt oc h l o r i t e ,
at rnadm
c eoguaonrftnasepta, t iatned,
m a g n e t i t eA. u g i t eo, l i v i n ea, n d / opr y r o x e n e
o r i g i n a l l yp r e s e n tb u th a v e
may h a vbee e n
now b e e na l t e r e dt oh o r n b l e n d e .
Thp
e l a g i o c l a s ce o m p o s i t i o n
c o n t r i b u t e tso
t h lei t h o l o g i c
i s often
d i f f e r e n c e sb e t w e e nt h ed i o r i t ea n dg a b b r o .Q u a r t z
p r e s aeim
nn to u ntuotps
O p h i stt u
iocb o p h i t i c
10%.
is
t e x t u r e si, nw h i c hp l a g i o c l a s e
partially
or
completely
e n c l o s e db yh o r n b l e n d e ,a r eo f t e np r e s e r v e d ,s u g g e s t i n gt h e
o r i g i n arlo c k
may h a vbee e n
a
g a b b r (ot a b l e
4).
However
and
h y p i d i o m o r p h i c - g r a n u lt ae rx t u raoerfsetperne s e n t
s u g g e s tt h a tt h er o c k
may h a v e b e e n i n p a r t
T
dh
i oer i t e / g a buhbnar d
o
s ergo
dn
e feo r m a t i o n
shearing
near
t h ec o n t a c w
t i t ht h ea l t e r e df a c i e s
P o l v a d e r a , G r a n i tw
e ,h e lraer g ae m
r o u ncot hsf l o r i t e
-
a diorite.
and
of t h e
and
..
P a g e 36
TABLE 4
D i f f e r e n c eB e t w e e nG a b b r oa n dD i o r i t e
( m o d i f i e d a f t e r Hyndman, 1 9 7 2 )
CRITERIA
DIORITE
GABBRO
plagioclase
An>50
An<50
composition
(laboradiorite,
(andesine,
bytownit e )
oligoclase)
Other
a u g i t e ,o l i v i n e ,
hornblende,
Minerals
hornblende,
pyroxenes,
clinopyroxenes
biotite
Associated
pyroxenites,
granodiorites,
R o c kT y p e s
anorthosites
q u a r t zd i o r i t e s
C o l o ro ft h e
graytogreenish
white
Plagioclase
gray
Texture
subophitic,
cumulus,
or
hypidiomorphic
granular
ophitic
NOTE:
M e t a m o r p h i s m may c h a n g e some
of
t h e s ev a r i a b l e s .
P a g e 37
biotite
are
f o u n df o
, r m i nsgc h i s t o szeo n e sT.h icso n t a c t
a p p e agr rs a d a t i o naanl d
is
p o o relxyp o s eQd u. a ratnzd
in
K - f e l d s( p raor b ambilcyr o c l oi n
ifnteec) nr e a s e s
a b u n d a n c en e a tr h ec o n t a c w
t i t ht h eP o l v a d e r aG r a n i t ea n d
o t h e rg r a n i t e s .
I n c l u s i o n s a r e f o u n dt h r o u g h o u tt h ed i o r i t e l g a b b r oa n d
e s p e c i a l l yi nt h es o u t h e r np o r t i o no ft h eo u t c r o pa r e a .T h e
to
i n c l u s i o n sa r eg e n e r a l l yf i n eg r a i n e d d
, ark
m a f i c r o c k( p l .
e x h i b i t i n gs h a r pc o n t a c t sw i t ht h ee n c l o s i n g
6).
some
in
L i g h t - c o l o r e lde u c o s o m ew
s i tm
h a f isce l v a g eos c c u r
a n 0 r i g i . n by.
p a r t s o ft h ed i o r i t e l g a b b r os u g g e s t i v eo f
(Pl.
m e t a m o r dp ihf ifce r e n t i a t i o n
f o l i a t e ad r k o s oe c c u r
(P1.
l i g h tg r a y ,
8).
a n dh a v e
as
7).
i n c l u s i o n us tpo
Q u a r t. za intde
50 cm.
across
Dark
f i, n e - g r a i n eadm p h i b o l i ti en c l u s i o nosc c u r
a n a p p e a r a n c ea n dc o m p o s i t i o n
similar t o t h e m a f i c
d i k e sH. o r n b l e n daenbdi o t i t ep,o s s i b ldye r i v efdr o m
the
d i o r i t e / g a b b r o ,o f t e n - r e p l a c e so r i g i n a lm i n e r a l sw i t h i nt h e
inclusions.
Large b l o c k so fs e d i m e n t s
Lemitar
Some
diorite/gabbro
t oh febsleo cam
krsea p p a b l e
F o l i a t i o na n d
a r e s c a t t e r e dt h r o u g h o u tt h e
( a f e w m e t e r s t o 1 0 meters a c r o s s ) .
(sec.
r e l i c t b e d d i n g a r e o f t e np r e s e r v e d M
. ost,
n o t a l l , of t h e s eb l o c k sa r ep r o b a b l yr o t a t e dx e n o l i t h s
opposed
7,
t o r o o fp e n d a n t s ,b e c a u s et h ea t t i t u d e
Map
1).
if
as
of f o l i a t i o n
PL.
6:
Photomicrograph
(lox, c r o s s - p o l a r s )
d i o r i t e / g a b b r ow i t h
of
a f i n e - g r a i n e ds e d i m e n t
inclusion.
PL.
7:
D i o r i t e / g a b b . r ow i t h
a s e d i m e n ti n c l u s i o n .
c---"--l
0.35 mm
PL. 8:
Amphibolite inclusion
in the diorite/gabbro.
Page 40
v a r i e s f r o mt h a t
o f t h eg e n e r a la t t i t u d es e e ni nC o r k s c r e w
Canyon.
Migmitization
M i g m i t i z a t i toL
hn
fee m i tda iro r i t e t g a b b or o
ccurs
s oatuh
litoen
hnteg
rru
cno
st h
w
invetieat hc t
m u s c o v i t e - b i o t i t eg r a n i t e .T h eg r a n i t e
is s t r o n g l yf o l i a t e d
9 1 , f o r m i ni rgr e g u l a r ,
n e at hri n
e t r u s i vc eo n t a (c Pt l .
f o l d e db a n d so fq u a r t za n df e l d s p a r .F o l d e dv e i n so fq u a r t z
mafic r o c k s o f t h e
a n df e l d s p a cr r o s s c u t h em e l a n o c r a t i c
L e m i t a r d i o r i t e / g a b b r o (Pl.
11
and
12)
1 0 )A
. g m a t i t i sc t r u c t u r e (sP 1 .
a n dl e u c o c r a t i cp t y g m a t i cf o l d so c c u lr o c a l l y .
a r e s u g g e s t i v e o f t h ei n t e n s e
B o u d i n a g es t r u c t u r e s( P l .1 3 )
s h e a r i n ga n ds t r e t c h i n g .
of
F o upro s s i b lme e c h a n i s m s
m i g m i t i z a t i ohna vbee e n
p r o p o s ebY
dya r d l e( y1 9 7 8 i)g: n e o ui n
s jection
an
, atexis,
external
metasom
maeattniasdm
mo, srepghriecg a t i o n .
of i n d i v i d u a x
l enoliths,
A g m a t i z a t i o na n dr o t a t i o n
i nt h e
as s e e n
Lemitar m i g m i t i t e sa,rlei k e l w
y h e r e v eerx t e n s i v e
m e l t i n gh a so c c u r r e d ,w h e t h e rp r o d u c e d
a noar t e cmt ei cl t s .
It
is
b yi g n e o u si n j e c t i o n
u n l i ktehx
laytte r n a l
m e t a s o m a t i s m o r m e t a m o r p h i cs e g r e g a t i o nc o u l dp r o d u c ee n o u g h
f l u i d t o c a u s er o t a t i o n s
of l a r g e
x e n o l i t h (sK i n g ,
1965).
PL. 9 :
PL. 10:
Strongly foliated muscovite-biotite granite.
Migmititic layers in t h e dioritejgabbro of t h e
Lemitar diorite/gabbro.
PL. 11:
Agmatitic structures in dioritefgabbro.
PL. $2:
Agmatitic structures in dioritefgabbro.
PL. 13:
Boudinage structures
in diorite/gabbro.
44
Page
i n the
T h ea p p e a r a n c ea n dc o m p o s i t i o no ft h el e u c o s o m e ss e e n
L e mm
i tiagrm i triet seaestdm
hj eaotbchfl eae nts t
m u s c o v i t e - b i o t i t eg r a n i t e .L e u c o s o m e sc a nb el o c a l l yt r a c e d
im
n
t htuo
es c o v i t e - b i o tgi rt ea n(iPt e1 .
indicating
that
clearly
101,
of t h em u s c o v i t e - b i o t i t e
i g n e o u si n j e c t i o n
g r a n i t ei n t ot h eL e m i t a rd i o r i t e / g a b b r op r o d u c e dt h eL e m i t a r
migmitites.
Geochemistry
A
a n d f o u tr r a c ee l e m e n t s( A p p e n d i x
. a n a l y z e df o re i g h m
t ajor
C).
was
r e p r e s e n t a t i svaem ptod
lhfeieo r i t e / g a b b r o
T shaem plloec a t i o anprsleo t t o
fe id
n2g..
Norms w e r e c a l c u l a t e d u s i n g
CIPW
a c o m p u t e rp r o g r a m( A p p e n d i x
T h ed i o r i t e / g a b b r of r o mt h eL e m i t a rM o u n t a i n s
S i 0 2 ,T i 0 2 ,F e 2 0 3 ,a n d
K20 a n dl o w e r
t h a no t h e P
r r e c a m b r i a nm a f i cr o c k sf r o m
is
New
(1954)
a v e rdai g
o er i t e .
Mexico
and
5).
is
A l l
h i g h e ri n
i n A1203, MgO, a n d C a O
a v e r a gA
e r c h e a bn a s a l t iacn d e s i t(et a b l e
Si02
c o n t e n tt,h d
eiorite/gabbro
C).
I n t e r mosf
h i g h etrh a N
n ockolds'
sfatihm
veeopfl e s
d i o r i t e / g a b b r oc o n t a i nn o r m a t i v eq u a r t z( A p p e n d i x
C).
an
TABLE 5
C h e m i s t r y of t h e M a f i c '
Si02
1
2
52.5
48.2
1.53
3
'
4
1.41
Ti02
14.2
A1203
13.0
Fe203* 1 2 . 1
14.5
8.20
5.49
MgO
CaO
9.00
9.50
2.05
2.57
Na20
0.56
0.53
K20
TOTALS 9 7 . 3 19 8 . 0 3
5
6
48.4
53.1
0.96
1.32
16.8 . 14.2
10.4
11.2
8.06
7.77
9.35
2.26 2.47
0.56 0.36
9 8 - 9 0 99 * 4 1
11.1
7
356
55
109
108
-
8
9
47.5 53.4 4 6 . 4
1 . 8 9 2.16 1 . 6 3
11.4 11.0 13.4
1 6 . 8 18.3 1 5 . 5
7.36 2.15 8 . 4 3
8.58 6 . 8 9 9.16
1 . 9 4 2.39 3.14
1 . 5 8 1 . 7 2 0.35
9 7 - 0 5 9 8 . 0 19 8 . 0 1
25
205
Ba
Rb
Sr
1
Rocks
366
47
150
108
11
. 191
t y p i c a la m p h i b o l i t eo fL a sT a b l a sQ u a d r a n g l e ,B a r k e r ,
1958
2
3
-
a v e r a g e of 6 a r e a so fP r e c a m b r i a nm a f i cr o c k s
s o u t h - c e n t r a l New M e x i c o ,C o n d i e
a n d Budding,
-
and metabasaltic
a v e r a g e of 1 0 a n a l y s e s o f m e t a t h o l e i i t e
1974
a n d e s i t e f r o m t h e T u s a s Mts., B a r k e ra n dF r i e d m a n ,
'
4
-
5
-
6
,
7
8
9
*
-
a v e r a g ed i o r i t e ,N o c k o l d s ,
a v e r a g eg a b b r o ,N o c k o l d s ,
1954
1954
a l , 1977
a v e r a g eA r c h e a nb a s a l t i ca n d e s i t e ,P e a r c e ,e t
a v e r a g eL e m i t a rm a f i cd i k e( a v e r a g eo f
a v e r a g eL e m i t a rd i o r i t e l g a b b r o( a v e r a g e
M a g d a l e n ag a b b r o ,C o n d i ea n dB u d d i n g ,
T o t a li r o ne x p r e s s e d
in
1979
as Fe203.
5 samples)
of 5 s a m p l e s )
1979
Page
G a b b r o o f Garcia Canyon
T hLe e m i t adri o r i t e l g a b b raontdhgea b b rooGf a r c i a
similar t e x t u r e s a n d
C a n y o'n( M a g d a l e ngaa b b r oh)a vvee r y
m i n e r a l o gai letsh, othudhagievfhyfee cr eh ne tm i c a l
c o m p o s i t i o n( sL o u g h l iannKdo s c h m a n
1 ,9 4 2S;u m n e1r ,9 8 0 ) .
Both
mafic
are
u inni t rsoulsddeeedri m ea nn tds
s u b s e q u e n it n
l yt r u dybeoydu n gPerro t e r o z ogirca n i t e s ,
i m p l y i n gt h a tt h et w om a f i cu n i t s
the
at
s a mtei m eT. hge a b b r oG
f a r c iC
a a n y oh
n abs e e d
na t e d
(1.5 b . y . ,W h i t e ,
by
Rb-Sr
may h a v eb e e ne m p l a c e d
1 9 7 8 ) a n df o u n dt ob eo fm a n t l ed e r i v a t i o n
i n i t i a l Sr86/Sr87
i s o t o p set u d i e sa, l t h o u g thh e
i s o t o p er a t i oo 0
f . 7 0 4( W h i t e ,
1 9 7 8 ) i s s u g g e s t i v eo f
some
c r uc sotnatla m i n adtTiifh
ofenec.rheeinn
m
c ei cs a l
c o m p o s i t i o nc o u l db ed u et od i f f e r e n c e si n h e r i t e df r o mt h e
s o cutorocnret a m i n a t i o n
e m p l a c e m e n tD
. ifferences
of
granitic
magmas
after
i n t h ed e g r e eo fc o n t a m i n a t i o na n d
metamorphism
c o u ladl saoc c o u nf tot rhdei s s i m i l a r i t y
c h e m i c a lc o m p o s i t i o n sb e t w e e nt h et w om a f i cu n i t s .
in
Page
47
Origin
of
l iTt hh oe lhoegt iecr o g e n e i t y
L etm
h ei t a r
a magma of o r i g i n a l
d i o r i t e / g a b b r oc o u l db ea c c o u n t e df o rb y
d i o r igttoae b b cr o m p o s i t i oH
n .o w e v e r ,
t hLee m i t a r
if
a d i o r i t et og a b b r o
d i o r i t e / g a b b r ow e r ed e r i v e df r o m
magma
f r otm
huep p m
e ra n t l oe t, h d
e ri o r i t e / g a b b r os h
s oub
l de
i n t h eP r e c a m b r i a nt e r r a i n
exposed
d o m i n a n t l yg a b b r o s
or b a s a l t s a r e s e e n .
C o n t a m i n a t i o nb yg r a n i t i c
a
gabbroic
o f New M e x i c oI. n s t e a d ,
magma
magmas o r c r u s t a l m a t e r i a l
c oauclcdo u n t
for
h e t e r o g e n e i t y o f t h eL e m i t a rd i o r i t e / g a b b r o .
magma
lt ihteh o l o g i c
As a
c o n t a m i n a t e da,l t e r i npga r tost fhgea b b r o i c
magma
a n d q u a r t dz i o r i t e
from
t hceo n t a m i n a t i o ontfhde i o r i t e / g a b b r o
magma
or
as
a
gabbroic
it coulb
decome
a s c e n d st o w a r d st h ee a r t h ' ss u r f a c e ,
d i o r i t eT. hqeu a r tgza b b r o
of
t o
a
may r e s u l t
by
granitic
l a st te a gd ei f f e r e n t i a fot ref a c t i o n a l
c r y s t a l l i z a t i o no ft h ed i o r i t e / g a b b r oo rb o t h .T h ep r e s e n c e
o fq u a r t zd i o r i t e sn e a rt h ei n t r u s i v ec o n t a c t ss u g g e s t st h a t
t hmea fbi co dpyr o b a b l y
was
c o n t a m i n a t ewdi g
t hr a n i t i c
magma.
TLheem idt ai or r i t e / g a b bc rooua h
ld
saboveee n
e m p l a c e d a s a g a b b r o ,a n ds u b s e q u e n ti n j e c t i o na n dm i x i n g
g r a n i t i c magmas w o u l da l t e rt h eg a b b r o
t o a d i o r i t eo re v e n
of
P a g e 48
to
a
as
q u a rdtizo r i S
t eu.fceha t u r e s
Lemitar d i o r i t e / g a b b r o w
, o u l db ec o n s i s t e n t
p r e s e n ti nt h e
w i tshu c h
a
modeL
l . a tdei f f e r e n t i a t i oon
t fhgea b b r o i c
magma c o u l d c r y s t a l l i z e
f o rt h e
migmitization,
a s a d i o r i t e ,a n dc o u l da l s oa c c o u n t
L e m i t a r m a f ibc o d y .
A c o m b i n a t i o no bf o t hi g n e o u s
a
i n j e c t iam
onn
idx ionf g
granitic
magma
in
differentiac
t ioarouelnsls d
ou l t
alna dt e
L et hmei t a r
diorite/gabbro.
T hper e s e n coseef d i m e n
an
tmd a f d
i ci ki n
eclusions
i s y o u n g etrh a n
Y n d i c a t e tsh atth L
e e m i t a dr i o r i t e / g a b b r o
t h es e d i m e n t sa n d
a t , l e a s to n ee a r l ys t a g eo fm a f i cd i k e s .
B e c a u fsoe l i a t i o n
inclusions,
is
preserved
in
some
of
th
a rek o s e
a p e r i oodmf e t a m o r p h i s m
o c c u r r ebde f o rteh e
i n t r u s i o no ft h eL e m i t a rd i o r i t e / g a b b r o .
MAFIC DIKES
Distribution
M a f idci k ei n
s trude
all
ot hfeex p o s ePdr e c a m b r i a n
r o c kesx, c etph
ctae r b o n a t i t eCs a. r e fm
u la p p i tn
ohg
fe
m a f i cd i k e si n d i c a t e s
a c o m p l i c a t e dh i s t o r yo ft w oo rm o r e
p e r i o d so fi n t r u s i o nt h a tc a nb er e c o g n i z e db a s e d
r e l a t i o n s h i p sT
. h ed i k e s t r i k ed o m i n a n t l y
on f i e l d
in a
northernly
P a g e 49
d i r e c t i o nw i t ha l m o s tv e r t i c a ld i p s .
A s e r i e so fu n m e t a m o r p h o s e dd i a b a s ed i k e sa l s oi n t r u d e
t hP
e r e c a m b r i a sn e c t i o n .
Tertiary
in
M o sottfh e sde i k easrpe r o b a b l y
a bg ee c a utoh
s fel aim
roc fek t a m o r p h i c
similar
c h a r a c at enrd
P h a n e r o z osi ec d i m e n t s .
(appendix
B)
d i kaferoseuinndt r u d itnhge
One s a m p l e
56)
(Lem
is
described
and
included
with
t h ae n a l y s e ostfh m
e afic
i s similar t ot h em a f i c
d i k e s .C h e m i c a l l y ,t h ed i a b a s ed i k e
dikes.
Description
a n d f i n e - g r a i n e da n d
T h em a f i cd i k e sa r eg r e e n i s h - b l a c k
may
i n c l u d ei n c l u s i o n so sf e d i m e n t a r yr o c k s .
a
v e i n sa n dc a r b o n a t i t ed i k e so f t e nc r o s s c u t
m a fdi ci k e s .
f o l i a t e da n d
In
Thin granitic
t h is ne c t i o m
n ,a f d
i ci k e s
f e wo tf h e s e
are s l i g h t l y
may e x h i b i st u b o p h i t i ct e x t u r e s T
. h e yc o n s i s t
o fg r e e nh o r n b l e n d e( 3 5 - 4 0 2 1 a, l t e r e dp l a g i o c l a s e( 3 0 - 3 5 % ) ,
g r e e n a n d brown b i o t i t e
(10-20$),
m a g n e t i t( e5 - 1 0 $ ) ,
and
v a r y i anm
g ouq
nou
tfsa r tczh,l o r i thee,m a t i tgea,r n e t ,
f l u o r i t ae n
, cda r b o n a t M
e . o r t at er x t u r eosf t eanc c o m p a n y
s e c o n d a r yc a r b o n a t e ,w h i l ec a r b o n a t ef l u i d sa s s o c i a t e dw i t h
t h ei n t r u s i o n
o f t h ec a r b o n a t i t ed i k e o
s f t e nf o l l o w e d
partiallyreplacedthese
and e a r l i e rd i k e s .
and
P a g e 50
A s e r i e s offo ut rh isne c t i o nasl o n g
a
i n t r u d e bd y
a
mafic
dike
c a r b o n a t i t de i k w
e e r set u d i e dA. d j a c e ntto
t hcea r b o n a t i tde i k et ,hm
e a f idc i keex h i b i t e edx t e n s i v e
a l t e r a twi ohcneorrer om
d ea dg n e thi toer,n b l e nadned,
feldspar are
(1-3b)
was
r e p l a cbeayd
r b o n a( p
t el .
Apatite
14).
i n t r o d u c iendttm
hoea fdi ickSeu. b o p h i t i c
t e x t u r e s were p r e s e n it n
a l l f o utrh i sn e c t i o n sF. u r t h e r
i s o b s e r v e da l o n g
f r o mt h ec a r b o n a t i t ed i k e ,l e s sa l t e r a t i o n
In
w i t thh de i s a p p e a r a n c oeaf p a t i t e .
t h se a m p l leo c a t e d
f a r t h e s tf r o mt h ec a r b o n a t i t ed i k e ,o n l ys l i g h ta l t e r a t i o n
was o b s e r v e M
d . a g n e t i ct eo r ehs o, r n b l e n daenf, ed l d s p a r
w e r eo n l ys l i g h t l yr e p l a c e d
b yc a r b o n a t e .
T h ef i e l de v i d e n c es u g g e s t st h r e ep e r i o d s
-
bm
y a f idci k e s
Stage
of
I, 11, a n d 111.
intrusion
T hper e s e n c e
of
m a f i c d i kien c l u s i o nws i t h itnhdei o r i t e / g a b b rsou g g e s t s
that
mafic
dikes
from
S t a g e I w e r ee m p l a c e dp r i o rt ot h e
intrusion
otfh L
e e m i t adr i o r i t e / g a b b r oM
. a f id
c i k e fsr o m
Stage
I1
i n tL
r uteh
dmedid
itoarri t e / g a b
an
bd
ro
s u b s e q u e n t l y were c r o s s c u tb yg r a n i t i ca n dp e g m a t i t ed i k e s
a n dv e i n s ,i n d i c a t i n gi n t r u s i o na f t e rt h ee m p l a c e m e n t
of t h e
d i o r i t e / g a b bbrbuoetf oerm
e p l a c e m teg
ohnrfeta n i t i c
complex.
Mafic
d i k ferso m
the
final
s t a g Se t, a g e
i n t r u d e d a l l o f t h eo l d e rP r e c a m b r i a nr o c k s ,i n c l u d i n gt h e
g r a n i t icco m p l e xb;udtindoi n
t t r u dt ehcea r b o n a t i t e s .
111,
PL.
14:
P h o t o m i c r o g r a p (h2 5 xc, r o s s - p o l a r ss) h o w i n g
, here
e x t e n s i f e c a r b o n a t i z a t i o n o f a m a f i cd i k e , w
c a r b o n a t e h a sr e p l a c e df e l d s p a rc r y s t a l s .
H
0.3m m
Page 53
Geochemistry
A r e p r e s e n t a t i v es u i t eo fs a m p l e sf r o mt h em a f i cd i k e s
was a n a l y z efdoeri g h t
e x p o s eitdnhLe e m i t aM
r ountains
m a j o ra n d
four t r a c ee l e m e n t s( a p p e n d i x
plotted
on
fig.
C).
T h es a m p l e sa r e
2.
T hmea f di ci ks ea m p l ec sabcneo m p a r ewdi o
t ht h e r
P r e c a m b r i amna f ri o
c c kf rso m
New
A r c h e a nb a s a l t i ca n d e s i t e( t a b l e
5 ) a n df o u n dt ob eh i g h e r
in
F e 2 0a3n d
K20
a nldo w e r
M e x i caonaadnv e r a g e
i n A1203, C a O , a n d Na20.
In
terms ot hfSei 0c2o n t e n
t hm
t ea f d
i ci ks ea m p l e, hs a v e
approximately
the
a v e r a g ge a b b r (ot a b l e
as Nockolds'
s a maem o u noStfi 0 2
5).
Two s a m p l eostfhm
e a f idci k e s
c o n t a i n e dn o r m a t i v eq u a r t z( a p p e n d i x
C).
(1954)
O R I G I N OF THE MAFIC
ROCKS
in
T h em a f i cr o c k o
s tfh eL e m i t a M
r o u n t a i np
s lot
9 1 , w i t ht h em a f i c
o f a n AFM d i a g r a m( f i g .
t h o l e i i t ef i e l d
the
d i k e sf a l l i n gc l o s et ot h el i n eb e t w e e nt h et h o l e i i t i c
and
c a l c - a l k a l i n ef i e l d s ,( u s i n gI r v i n ea n dB a r a g a rd e f i n i t i o n ,
1971).
T h e r e i s noob v i o ut rse nbde t w e et n
hme a f i c
a
f e l s ir co c k a
s ,l t h o u g h
and
bimoda
p lo p u l a t i oenx i s t s .
c h e m i c a li n d i c e sh a v eb e e np r o p o s e d
Two
a s a m e a s u r eo fm a g m a t i c
f r a c t i o n a t i o n o f m i n e r a l s ;t h em a f i ca n dt h ef e l s i ci n d i c e s
(Simpson, 1954).
similar
TLheem i . st a rm p p
l el so t
t ot h eS k a e r g a a r dt r e n d( f i g .
t hme a f ir co c k s
may
Metamorphism
may
bdee r i v ef d
rom
on
trend
a
101, s u g g e s t i n gt h a t
a
similar
source.
bree s p o n s i b lfeotrhsec a t t eordf a t a
p o i n t s e e ni nf i g 1. 0 .
Two m a f i cb o d i e s
three
a r e e x p o s e d i n t h eL e m i t a rM o u n t a i n s
-
s t a g e s o fm a f i cd i k e sa n dt h eL e m i t a rd i o r i t e / g a b b r o .
M o s tm a f i c
Budding,
magmas o r i g i n a t e i n t h eu p p e rm a n t l e( C o n d i ea n d
1 9 7 9 1 , a n d i t i s c o n c e i v a b l et h a tt h em a f i c
magmas
p r o d u c i ntghm
e a f irco c ksse ein
tnhLe e m i t aM
r ountains
c o u l dh a v ee m e r g e df r o mt h eu p p e rm a n t l e
as w e l l .
A l t h o u g hn od e f i n i t ec h e m i c a lt r e n d sb e t w e e nt h em a f i c
it
d iLtakheneem
ds idtiaorr i t e / g a b ebxr ios t ,
c o n c e i v a b l teh abt o t ah r de e r i v e fdr o m
a
similar
is
source.
F
A - N a O+K20
2
F - FeO
M MqO
SKAERGAARD
-
FOR EXPLANATIONOF
".
SYMBOLS S E E
FIG.8
DASHED CURVESEPARATES
CALCALKALINE FIELD (BOTTOM)
FROMTHOLEIITICFIELD(TOP)
F R O M I R V I N E AND BARAGAR,1971
\
GROUP 2
GRANITES
Y
A
"
v
V
V
v
V
"
v
N
100 90
,SKAERGAARD
LEMITAR
D I O R I T E / G A B B R ~
TREND
-
80
70
r
-
60 MI
50 -
OKONJEJE
THOLEIITIC
40 -
SERIES
301
20
F O R EXPLANATION O F
SYMBOLS SEEFIG.
8
I
0
0
IO
20
30
40
50
60
70
80
90
100
FI
.M I =
(FeO+ Fe203) x 100
MAFICINDEX
M g O + FeO+Fe203
FI
(Na20 + K20)
X
100
C aO+ Na20+%0
FIGURE 10:
M A F I C - F E L S I CI N D E X
ROCKS
F E L S I CI N D E X
PLOT OF THE LEMITAR IGNEOUS
(FROM SIMPSON, 1954)
T h ed i f f e r e n c e sb e t w e e nt h et w om a f i cu n i t sa r ee x h i b i t e d
-
i n q u a r t( zS i 0 2c1o n t e n t s
t hde i s s i m i l a r i t y
or
d i k ehs a v i n lgi t t l e
in
c o n t a i nqiunagr t z
no
t hme a f i c
q u a r tazntdhdei o r i t e / g a b b r o
a m ouupn t s
to
d i o r i t e / g a b b r ow e r ec o n t a m i n a t e d
If
10%.
the
by g r a n i t i c magma a t some
it
p o i n t i n i t s e a r l hy i s t o r y ,
by
is
w i t h itnhbeo u n dosf
p o s s i b i l i ttyh at h
tm
e a f idci k easntdhdei o r i t e / g a b b r o
o r i g i n a t e d f r o m t h e samu
e pper
of
mafic
m a n t l e s o u r c eT
. h r e es t a g e s
d i k ei n t r u s i o nw o u l db ec o n s i s t e n w
t ith
a unique
sourcS
e .i m i l ac rh e m i s t r i ebse t w e et n
ht e
h r es et a g eosf
m a f idc i k easn tdhde i o r i t e / g a b b r sou p p o rstu c h
a model.
H o w e v esre, p a r ast oe u r c fetosh
m
rea fdi ci k ae nts hde
d i o r i t e / g a b b r oc o u l de x i s t .
G R A N I T I C COMPLEX
Introduction
G r a n i t ir co c k s
m a kuaepb o tuht r ef o
e u r t ho
t hsf e
in
e n tei x
r ep o sPu
or ref ec a m b r ri ao nc k s
M o u n t a i n (sf i g .
2).
h a v eb e e nd i s t i n g u i s h e do n
b e t w e e nt h e m
S i xv a r i a t i o n o
so
f n eo r
more
plutons
Map 1, a l t h o u g ht h er e l a t i o n s h i p
i s u n c e r t a i nb e c a u s eo ft h el a c ko fa n y
r e l a t i o n s h i p sT
. hese
tLheem i t a r
map u n i t sa r e :
field
(1) g n e i s s i gc r a n i t e
(2)
m u s c o v i t e - b i o t i tge r a n i t e
(3)
biotitg
eranite
(4)
leucogranite
(5)
P o l v a d e rG
a ranite
(6)
p e g m a t i t e sa n dq u a r t zv e i n s
T h eg n e i s s i cg r a n i t ei n t r u d e st h eb a s eo ft h es e d i m e n t s
and
is
n o ti nc o n t a c tw i t ht h eo t h e rg r a n i t e sn o rw i t ht h e
L e m idt ai or r i t e f g a b b r o .
g n e i s s igc r a n i t e
A
(Map
1).
fpeewg m a ttcihdut eeot s
T hgen e i s s igcr a n i tceo u lbde
in
o l dtehra
th
one
t hge rr a n i t ee xs p o s e d
is
M o u n t a i nsst;r o nf o
gliation
present
tL
he mitar
i n t hgen e i s s i c
g r a n i taen adb s e nftr o m
from
t hoe t h egr r a n i t e s .
is
g n e i s sgi cr a n i t e
g n e i s s i cg r a n i t e
sediments.
If
the
o l d et rh, et h
fnoe l i a t i o
tohnf e
is possiblyrelatedtothefoliationofthe
I t i s d i f f i c u l tt of o l i a t eo n eg r a n i t e( g n e i s s i c
g r a n i t e )w i t h o u ta f f e c t i n gt h eo t h e rg r a n i t e s
i n t h e Lemitar
M o u n t a i n s ,u n l e s st h eo t h e rg r a n i t e sw e r ee m p l a c e da f t e rt h e
f o l i a t i o no c c u r r e d P
. e g m a t i t e sa n dq u a r t zv e i n sa r e
common
t h r o u g h o ut thsee d i m e n t st ,hLe e m i t adri o r i t e f g a b b r oa,n d
t h e P o l v a d e rga r a n i t eT. hge r a n i t irco c k s
from
a
similar
s o u rbceec a tusohisfem
e ilarity
c o m p o s i t i o na n dt e x t u r e .
may
bde e r i v e d
in
G n e i s s i cG r a n i t e
T h eg n e i s s i cg r a n i t ec r o p so u t
p o r t i o no ft h e
a r e a (Map 1 ) a n d i s b o u n d e d on t h e
mapped
a b r e c c i a t e df a u l tz o n e( f o r m i n ga na r r o y o )a n d
s o u t hb y
east
the
i n t h ee x t r e m es o u t h e r n
and
west
on
bu
y n c o n f o r m i t i ew
s i t thh P
ehanerozoic
l i m i t o ef x p o s u r e
s e d i m e n t sT
. h en o r t h e r n
an
is f o r m ebdy .
i n t r u s i vceo n t a cwt i tthhsee d i m e n t sa,ntdh idni k eosf
g n e i s s i cg r a n i t ei n t r u d et h es e d i m e n t sa l o n gt h ei n t r u s i v e
contact.
S ePvreercaalsm
e am
v
dbneirakd
irfaei nlsc
greenish-blacd
k i a b a s de i k e osuf n c e r t a i an g ien t r u d teh e
g n e i s s i cg r a n i t e .P h a n e r o z o i cl i m e s t o n ec a p st h eg r a n i t e
a
on
f e wo tfh eh i g h e hr i l l sP. e g m a t i t ed i k e as n dv e i n as r e
rare.
T h e g n e i s s i c g r a n i t e i s a s t r o n g l yf o l i a t e d( s e e
151,
p i n k i s h - g r a yt om e d i u m - g r a y ,c o a r s e -t om e d i u m - g r a i n e d
a
q u a r t z - m o n z o n i tw
e ,e a t h e r i nt o
g
sand.
P1.
'
r e d d i s h - o r a n ga er k o s i c
T h eg r a n i t ec o n s i s t so q
f u a r t z( 3 0 - 3 5 % ) K
, -feldspar
( 2 5 - 3 0 % ) p, l a g i o c l a s e
(20-25%),
b i o t i t e( 1 0 - 1 5 $ ) a, n dt r a c e
a m ohueonm
ft asm
at inat deg n e t i t e
(fig.
8).
Mortar
t e x t u r easroef t edne v e l o p e dT.h igsr a n i tdei f f e rf sr o m
o t h ePrr e c a m b r i agnr a n i t eit n
sh e
Lemitar
s t r o fnogl i ' a t i p
o rno d u csbety
dr o n gal lyi g n be ido t i t e
c r y s t a l as n d
by
t hlea cokm
f a f iacnadb u n d a nste d i m e n t
M o u n t a ibnys
PL.
15:
P h o t o m i c r o g r a p h (25x, c r o s s - p o l a r s )
g n e i s s i cg r a n i t e .
of
U
0.3 mm
Page 6 1
i n c l u s i o n sI.n c l u s i o nostfhaer k o saerfeo u n adl o n tgh e
16),
i n t r u s icvoen t a( cPtl .
bmuat if ni cc l u s i oanr se
absent.
M u s c o v i t e - b i o t i t eG r a n i t e
T hmeu s c o v i t e - b i o t i g
t er a n i ct er o po sn
uo
t rth
C o r k s c r e w' C a n y o nw
, here
'
of
i t i s i n i n t r u s i v e or f a u l tc o n t a c t
(as previousld
y i s c u s s e ds, e S
e edimentarR
y o c k sw
) i t thh e
s e d i m e n t so nt h es o u t ha n dt h eL e m i t a rd i o r i t e / g a b b r oo nt h e
north,
i t o c c u p i e sl e s st h a n
a f o u r t ho f
a s q u a r ek i l o m e t e r .
M a f idci k ea snsde v e r aTle r t i a rdyi k ei n
s t r u dt eh e
m u s c o v i t e - b i o t gi trea n i S
t em. lael nl s e s
of
d agrrke e n
a s x e n o l i t h s ,s u g g e s t i n g
c h l o r i t es c h i s ta n ds e d i m e n t so c c u r
a n i n t r u s i v er e l a t i o n s h i pw i t ht h es e d i m e n t s .M i g m i t i z a t i o n
Lemitar
o c c ua rl sotinhnget r u s icvoen t awcittthhe
diorite/gabbro
as
d i s c ueL
sa(sersem
leidei tra r
diorite/gabbro).
T h em u s c o v i t e - b i o t i t eg r a n i t e
is a
s l i g h t l yf o l i a t e d ,
p i n k i s h - g r a yt og r a y i s h - p i n k f, i n e - g r a i n e dq u a r t zm o n z o n i t e
or g r a n i t e .
I t d i f f e rf sr o tmhoet h eg rr a n i t e s
in
the
L e mM
i t aoru npttrhab
eeislynae(sornog
fcfetee n
m e g a s cpofrplioam
im
cfka)uersyc o( vp il t. e
P o r p h y r i t i c ,w h i t ea n db l a c kv a r i e t i e sa r ef o u n da l o n gt h e
c r e s to ft h ew e s t e r n m o s tr i d g e .T h er o c kc o n s i s t so fq u a r t z
18).
PL.
16:
A r k o s e i n c l u s i o nw i t h i nt h eg n e i s s i cg r a n i t e .
P a g e 63
( 3 0 - 4K
0%
- f )e,l d, s( 1
p0
a r- 3 p0 l%
a g) ,i o c l a s e ,
An40-50
( 2 0 - 3 5 2b1i,o t i(t5e - 1 0 %m) ,u s c o v i(t3e - 1 0 %a)n
t,rda c e
a m o umnoatfsg n e t iht ee ,m a t i t e ,
and
8).
c a l c i(t fei g .
M o s a i ct e x t u r e sd o m i n a t e .
B i o t i t eG r a n i t e
The b i o t i t eg r a n i t ei n t r u d e st h ec e n t r a la n dn o r t h e r n
It
p o r t itLohoenefm
s i dt ai or r i t e / g a b b r o .
often
is
g r a d a t i o n aw
l i t ht h el e u c o g r a n i t ea n df o r m st h ec r e s t s
a s p o d sa n d
t h er i d g e sa n da p p e a r
bmya frioc c kTs h
.g er a n i t e
of
s m a l l i s l a n d ss u r r o u n d e d
may
represed
n it k ea sn d / o r
plugs.
The b i o t i t e g r a n i t e
i s a g r a y i s h - p i n kt og r a y ,f i n e -t o
m e d i u m - g r a i n e d ,q u a r t zm o n z o n i t ea n dd i f f e r sf r o mt h eo t h e r
L e m i t aM
r o u n t a iP
n r e c a m b r i a gn r a n i t e s
by
n a t u r ea n dg r a n o p h y r i ct e x t u r e( p l .
its
fine-grained
I t i s c o m p o s eo
df
17).
q u a r t(z3 0 - 4 0 % )K, - f e l d s p a(r3 0 - 4 0 2 1p,l a g i o c l a s e ,
An40-50
( 2 0 - 3 0 % ) , b i o t i t( e5 - 1 0 % a) ,nt dr a caem o u n tohsfe m a t i t e ,
8).
mhaogrnanenb(tdfli eti egn,.d e
g r a n o p h y r i tce x t u r e
is
w e ldl e v e l o p e d
i n t h i ns e c t i o n so f
it
t hb ei o t i gt er a n i t de i, s t i n g u i s h i n g
Distinctive
f r ot o
m
h teh e r
g r a n i t e si nt h eL e m i t a rM o u n t a i n s G
. r a n o p h y r i ct e x t u r e
i n d i c a ct er y s t a l l i z a t i o n
at
a
eutectic
M o s a i ca n dp o r p h y r i t i ct e x t u r e sa r ea l s o
( H y n d m a1n9,7 2 ) .
common.
may
PL. 17:
Photomicrograph (25x, cross-polars) of
a
muscovite-biotite granite.
PL. 18: Photomicrograph (25x, cross-polars) of biotite granite
showing granophyric texture.
H
0.3mm
Page 65
Leucogranite
T hl e u c o g r a n i it n
e t r u d et hsc ee n t r a n
lndo r t h e r n
p o r t i o notsh
fLee m i t adri o r i t e / g a b b raonddi f f e rf sr o m
i t s c o a r s e rg r a i n
o t h e rg r a n i t e si nt h eL e m i t a rM o u n t a i n sb y
It i s often
g r a d a t i o n aw
l ith
the
s i z ae n d
whitish
color.
b i o t i t eg r a n i t ea n df o r m st h ec r e s t so fr i d g e s
small
a n d .o c c u r s
as
i s l a n d s u r r o u n d e db ym a f i cr o c k as l o n gt h ea r r o y o s
(Map 1).
T h el e u c o g r a n i t ep r o b a b l yr e p r e s e n t d
s i k e as n d / o r
plugs.
T h el e u c o g r a n i t e
i s a w h i t ea n db l a c k c, o a r s e - g r a i n e d
rocT
k .hger a n i ct eo n s i s o
et sq
f ua m
l o u no
q
t sfu a r t z ,
p e r t h i t i cK - f e l d s p a r ,
a n d p l a g i o c l a s e ,w i t ht r a c ea m o u n t so f
b i o t i t e ( < 5 % ) a n dm a g n e t i t e
8).
(<l%
f i ,g .
P o l v a d e r aG r a n i t e
T h eP o l v a d e r aG r a n i t e( W o o d w a r d ,
mapped a r e a a n de x t e n d sn o r t h w a r df o r
n o r t h e r nt h i r do ft h e
abouthree
km.
1971) c r o p so u ti nt h e
T h i s g r a n i t ec o m p r i s e sa b o u t h r e ef o u r t h s
o tfh eP r e c a m b r i a nr o c k es x p o s e di nt h eL e m i t a M
r ountains
( s efei g .
2).
A medium-
and
tcoo a r s e - g r a i n ef da c i e s
f a c i easrdei s t i n g u i s h eodn
Map
1,
w i tthh e
an
altered
medium-
to
c o a r s e - g r a i fnaecb
diem
etiesho
nxesgtte n s iTvhee.
southern
limit o fe x p o s u r eo ft h e
medium-
t oc o a r s e - g r a i n e d
Page 6 6
f a c i e s i s f o r m e d by a n o r t h e a s t - t r e n d i n gi n t r u s i v e
contact
(as
fault
p r e v i o udsi lsyc u s sL
wteehidm
te)hi t a r
l i m i t s oef x p o s u r e
d i o r i t e j g a b b r oT
. h ew e s t e r na n de a s t e r n
are
or
f o r m ebdfya u l t s
a n d u n c o n f o r m i t i ews i tPhh a n e r o z o i c
s e d i m e n t sa n dv o l c a n i c s .
i s l o c a t e ds o u t h w e s to ft h e
T h ea l t e r e df a c i e s
medium-
I t i s b o u n d e d on t h es o u t h ,w e s t ,
t oc o a r s e - g r a i n e df a c i e s .
a nndo r tbh
fya u l tasnudn c o n f o r m i t i ews i tPhh a n e r o z o i c
s e d i m e n t sT.heea s t e r n
i s f o r m ebdy
oefx p o s u r e
limit
a
g r a d a ti L
inoet n
rm
ctuahow
islen
tiiatvtrah
ec t
dioritejgabbro.
are
B o t hf a c i e o
s tfh eP o l v a d e r aG r a n i t e
m a f i ca n dc a r b o n a t i t ed i k e s T
. he
medium-
intruded
by
t oc o a r s e - g r a i n e d
of
f a c i e so f t e nc o n t a i n si n c l u s i o n so fm a f i cr o c k sa n d
gray
a n dg r e e nc h l o r i t es c h i s t .
The
mediumGranite
is
t oc o a r s e - g r a i n e df a c i e s
a p a l er e d ,
medium-
t oc o a r s e - g r a i n e d s, l i g h t l y
a
foliated
rock
t h aw
t e a t h e r tso
s a n dT.h igsr a n i tceo n s i s t s
t h eP o l v a d e r a
of
m o d e r a toe r a n gaer k o s i c
of e q ua m
l o u n oq
t sfu a r t z ,
p l a g i o c l a s e a, n dK - f e l d s p a r w
, i t hv a r y i n gt r a c ea m o u n t so f
biotith
e ,o r n b l e n d e ,
and
p o r p h y r i t it ce x t u r easroef t epnr e s e n t
G r e e na n dg r a ys c h i s t o
, f t e ns e v e r a lm e t e r sl o n g o
, ccur
i n c l u s i o n sw i t h i nt h eg r a n i t e .
8).
m a g n e t i (t fe i g .
in
Mortar a n d
t h isne c t i o n .
as
P a g e 67
T h ea l t e r e df a c i e so ft h eP o l v a d e r aG r a n i t e
is
poorly
e x p o s e adn bd a d l w
y e a t h e r e dP. e g m a t i t e sm, a f idc i k e sa,n d
P h a n e r o zm
o i cn e r a l i z a toi o
cw
cn ui g
trthrhiaenn i t e .
M i n e r a l i z a t i ocno n s i s t s
of
q u a r t zf ,e l d s p a ra ,nbda r i t e .
Some g a l e n a ,c a l c i t e ,a n dc o p p e rm i n e r a l sa r ea l s op r e s e n t .
F r e ssha m p l e s
of t h ae l t e r e fda c i eas r e
c o m p o s i t i o an n tde x t u r tetoh e
in
similar
medium-
t co o a r s e - g r a i n e d
f a c i eTs h
.r oe c akbrsel a ca k
nd du s kr eyd ,
medium-
c o a r s e - g r a i n egdr a n i t eTs .hg er a n i ct eo n s i s t s
(25-p
3 l0a%
g )i o
, clase,
to
of q u a r t z
An40-45
( 2 0 - 2p 5e %
r t )h,i t i c
K - f e l d s p a r( 3 0 - 3 5 % ) b
, i o t i t e( 1 5 . - 2 0 % ) a, n dt r a c ea m o u n t s
of
h o r n b l e n d em, a g n e t i t ea ,nhde m a t i t eS.u b m o r t at re x t u r e
is
p r e s e n ta n dg r a n o p h y r i ct e x t u r e
i s o f t e np r e s e r v e d .
I n c l u s i o n s o f s t r o n g l fyo l i a t e qd u a r t az n fde l d s p a r ,
s e d i m e n t s g, r a ya n dg r e e ns c h i s t a, n dm a f i ci n c l u s i o n sa r e
s c a t t e r e tdh r o u g h o u tD. i o r i t i tcg
o a b b r o i icn c l u s i o n as r e
f o u nadl o nt g
hi n
e t r u s i vc eo n t a cItn. c l u s i o na sr e
common t h a n i n t h e
T h ea l t e r a t i o n
r e s u l t sf r o m
medium-
more
t oc o a r s e - g r a i n e df a c i e s .
of t h i sf a c i e s
s o m ec o m b i n a t i o n
of t h eP o l v a d e r aG r a n i t e
o f t h ef o l l o w i n g :
(1) p a r t i a la s s i m i l a t i o no fs e d i m e n t sa n d
d i o r i t e / g a b b r or o c k s
(2)
s h e a r i n ga n dt e n s i o n a ls t r e s s
(3)
r e g i o n aml e t a m o r p h i s m
P a g e 68
(4)
f e n i t i z a t i o na s s o c i a t e dw i t ht h ei n t r u s i o n
of
t h ec a r b o n a t i t e s
(5)
h y d r o t h e r m a la l t e r a t i o np r o d u c e d
b yP h a n e r o z o i c
m i n e r a ls o l u t i o n s .
S m ablllo csokefsd i m e n t
d i o r i t e / g a b bor c
oc u r
and
w i t h itnhael t e r efda c i eotsfhPe o l v a d e rgar a n i taen d
p a r t i a al s s i m i l a t i o no tf h e s es e d i m e n t sa n dd i o r i t e / g a b b r o
in
b l o c k sa l o n gt h es o u t h e r ni n t r u s i v ec o n t a c tc o u l dr e s u l t
t hber i c k - r e db,a d leyr o d eadl t e r efda c i esse eitnnh e
s t r e s s h a so f t e n
L e m i t aM
r o u n t a i n sS. h e a r i n ga n dt e n s i o n a l
occurred
as
e v i d e n cnbeoydr t h e a s t - t r e n d ilnagy eorfs
f o l i a t eqdu a r t z
and
feldspar
in
some
o u t c r o p s (Map 1 ) .
F e n i t i z a t i o na s s o c i a t e dw i t ht h ei n t r u s i o no f
body
at
i n t h ea l t e r a t i o no ft h e
d e p t hc o u l da l s or e s u l t
g r a n i taes, s u m i nt hg a t
a
carbonatite
a
I
c a r b o n a t ibt eo d y
is
at
depth
b e n e a tt hhai lst e r ef ad c itoeh
Pfseo l v a d e gr ar a n i t e .
H y d r o t h ea rl m
t ear la t i o n
is
s u p eor li d
meoprno s e d
m e t a m o r p h i s ma n da l t e r a t i o n ,c o m p l i c a t i n ga n yi n t e r p r e t a t i o n
w h i c hm i g h th a v eb e e np o s s i b l e .
P e g m a t i t e sa n dQ u a r t zV e i n s
G r a y i s h - p i n ka n dw h i t ep e g m a t i t e
an
vd
e i innst r u tdP
heeo l v a d eG
r ar a n i tteg
h,n
eeissic
g r a n i ttehL, ee m i t da ir o r i t e / g a b b r aon,t hd
sediments.
a n d w h i t eq u a r t zd i k e s
P a g e 69
Some
pt heoegf m a tviethei n
ab v
sef oe lndTe h
d e.
o f t h se i m p l tey p ec, o n s i s t i n g
p e g m a t i t e as r e
mica,
f e l d s p a qr ,u a r t z ,
and
a
trace
of
unzoned
a m o ueonpft i d o t e .
Thesd
e i k e as n d
v e i n as r d
e i s c o n t i n u o u sw
, ith
a
s t r i k ea n do f t e nf o r mp o d - l i k eb o d i e ss u r r o u n d e d
northerly
by t h e h o s t
in
r o c kItn
.hger a n i t en ,u m e r o upse g m a t i tdei k er sa n g e
a f e w cm.
t h i c k n e s sf r o m
It i s p o s s i b l e
t os e v e r a lm e t e r s .
a f i n a l s t a g eo ft h eP o l v a d e r aG r a n i t e .
t h a tt h e yr e p r e s e n t
Geochemistry
T hger a n i t ir co c kasreei t h eqru a r tmz o n z o n i t eosr
( L e m 126) i s a g r a n o d i o r i t e
g r a n i t e sh,o w e v eornsea m p l e
(fig.
8).
Group
I
both
groups
G e n e r a l l yt,h ge r a n i t e s
and
Group
I1
(table
-
f a l l i n t o t wgor o u p s
6 a n df i' g .
9 , 11, a n d 1 2 ) ;
9).
f a l l w i t h i nt h ec a l ca l k a l i n ef i e l d( f i g .
Theg
s er o u p i n g
b sr o a d cl yo r r e s p o n
C
t odo n d i eh' si g h
( G r o u p I ) a n dh i g hS i
and
7).
More
Ca
t r a ceel e m e n t
d a t a a r ree q u i r e tdfou r t h e r
d i f f e r e n t i a t eb e t w e e nC o n d i e ' h
s i g hS ai n dh i g h
Metamorphisa
mnodt h earl t e r a t i o n
L e m i t a rg r a n i t e s ,
t h eg e n e r a l
R
d iba(-gfSirrga .m
6
or h i g h K ( G r o u p 11) g r o u p s( t a b l e
shown
by
trend
K
may
h a vaef f e c t etdh e
t h es c a t t e ro fp o i n t s
away
from
o f New M e x i c o
Precambrian
g r a n i t e os n
12).
groups.
D e sapl ti et er a t i o n
a
and
TABLE
Summary of t h eC h e m i s t r y
1
6
of t h e Lemitar Mountain Granites
4
3
2
si02
66-70%
73-76%
66-73%
70-77%
CaO
1.5-3%
(1.5%
1.7-4%
0.9-2%
MgO
0.8-1.5%
(0.8%
0.6-2.546
(1.
K20
(4%
3-6%
2.5-4%
4-5%
Mn
550-900 ppm
200-450 ppm
1
-
G r o u p I g r a n i t e s ,L e m i t a rM o u n t a i n s
G n e i s s i c GraniteandBiotiteGranite
2
-
Group I1 g r a n i t e s , L e m i t a r M o u n t a i n s
P o l v a d e r aG r a n i t ea n dM u s c o v i t e - b i o t i t e
3
4
-
H i g h C a g r a n i t e ,C o n d i e ,
granite
1978
H i g h K a n dH i g hS ig r a n i t e ,C o n d i e ,
1978
4%
FIGURE 11:
CaO-No20-K20
PLOT OF THE IGNEOUS ROCKS
FROM THE LEMITAR MOUNTAINS.
A
TREND
BETWEEN
LEMITARSAMPLES.DASHEDLINES
BUDDING, 1978).
NOTETHE
THE
LACK
\
OF
( S POPULATIONS
O L I D LINES ARE
A R E FROM CONDIEAND
,- "
I
\
300
K
...HIGH
....
..
\
I
I
\
\
\
HIGH c o
IO0
R b 50
10
FIGURE 12:
Rb-Sr PLOT O F THELEMITARGRANITES.FIELDS
SHOWING CRUSTAL THICKNESS ARE
FROM
CONDIE,
1973. F I E L D S O F HIGH Ca, .HIGH S i , AND HIGH K GRANITES
(DASHED LINES) ARE FROM CONDIE,
1978. SOLID LINES
R E P R E S E N T F I E L D S OF GROUP I AND 2 FROM THE LEMITAR
MOUNTAINS.
TABLE 7
CHEMISTRY OF THE GRANITES
1
Si02
Ti02
A1203
Fe203"
MgO
CaO
Na20
K20
TOTAL
2
2
3
4
5
6
7
8
-
4
68.0
0.78
14.3
6.46
1.05
73.5
76.4
74.2
0.46
0.07
0.45
13.6
1
3.2
12.5
3.66
0.95
4.43
0.47
0.05
0.44
1.04
2.03
0.95
1.07
3.03
3.67
3.45
3.69
4.81
4.40
5.20
3.94
9 9 . 4 101.31 1 0 1 . 2 9 100.25
B a517780816
100
820
1155
1279
S2r2 6
77
71
Rb
168
1
3
2183 5 0 1 4105 0
5
' 6
7
76.1
69.8 69.1
0 . 7 9 0.63 0.19
12.2
1 4 . 4 12.6
8 . 0 5 4.48 1 . 7 2
0.93 1 . 4 1 0.11
1 . 9 8 2 . 6 9 0.70
3.03
3.22
3.48
3 . 8 5 3.53 4.63
1 0 0 . 6 3 99.46 9 9 . 5 3
37
110
147
8
72.3
0.40
14.~3
2.76
0.51
1.35
3.08
4.79
99.49
779
255
242
274
Two mica g r a n i t e ,S t .F r a n c o i s ,M i s s o u r i ,K i s v a r s a n y i ,
1 9 8 0 (1 s a m p l e )
A v e r a g em u s c o v i t e - b i o t i t eg r a n i t e ,L e m i t a rM o u n t a i n s
( 3 samples)
A v e r a g eP o l v a d e r ag r a n i t e ,
Lemitar Mountains ( 2 s a m p l e s )
A v e r a g eb i o t i t eg r a n i t e ,L e m i t a rM o u n t a i n s
( 3 samples)
A v e r a g eg n e i s s i cg r a n i t e ,L e m i t a rM o u n t a i n s
( 2 samples)
A v e r a g eH i g h - C ag r a n i t e ,
N.M.,
C o n d i e , 1 9 7 8( 9
samples)
A v e r a g eH i g h - S ig r a n i t e ,
N.M.,
Condie, 1978 ( 1 2 samples)
A v e r a g e High-K g r a n i t e , N . M . ,
C o n d i e , 1 9 7 8( 1 5
samples)
NOTE:
2 a n d 3 c o m p r i s eG r o u p
I1 g r a n i t e s a n d
I granites.
c o m p r i s eG r o u p
4 and 5
Page 74
i t i s a p p a r e n tt h a tt h eg r a n i t i cr o c k s
m e t a m o r p h i ce f f e c t s ,
were e m p l a c eidn
t h i(cf ki g .
a
was
c o n t i n e n t ac lr u swt h i c h
1979).
C o nB
adnuidd
eding,
12;
>25
km.
This i s
a s s u m i n gt h a tt h ec r u s t a lt h i c k n e s sg r i dp r o p o s e db yC o n d i e
( 1 9 7 3 ) c a nb ea p p l i e dt os u c hg r a n i t e s .
Origin
E x p e r i m e n t a l c, h e m i c a l a, n di s o t o p i ce v i d e n c ei n d i c a t e
thag
t ranitic
Mountains,
magmas
magmas,
such
Lemitar
a s t h o s fe o u n d
in
the
of
may f o r mb yf r a c t i o n a c
l rystallization
or
C o n t a m i n a t i oo nf
p a r tm
i aell t i n g
by
a
granitic
magma
of
lt o
hw
ec re ur s t .
of
e i t h eorr i g i n
mafic
by
as
c r u s t aml a t e r i aclo u lpdr o d u chee t e r o g e n e o ugsr a n i t e s
f o u n di nt h eL e m i t a rM o u n t a i n s .
Geochemica
ml o d e
s tl u d i eosn
g r a n i t e si n d i c a t et h a t
30
New
-
M e x i cPor e c a m b r i a n
50% p a r t i a lm e l t i n g
of s i l i c e o u s
g r a n u l i t e s i n t h el o w e rc r u s tc o u l dp r o d u c eg r a n i t i c
similar i n c o m p o s i t i o n t o g r a n i t e s
of C o n d i e ' sh i g h
melts
C a group
( C o n d i e , 1 9 7 8 1 , w h i cbhr o a d lcyo r r e s p o nttdohG
eroup
granites
in
h i g hS ai n dh i g h
granites
in
I
t hL
e e m i t aM
r o u n t a i n sG. r a n i t efsr o m
Condie's
K,
which
broadly
correspond
to
t hLe e m i t aM
r o u n t a i n sc ,o u lbdper o d u c e d
f r a c t i o n a lc r y s t a l l i z a t i o n
o f g r a n o d i o r i t e magmas.
Group
II
by
T h i s may
i m p l yt h a tt h eL e m i t a rg r a n i t e s
m e c h a n i s m st h a t
may b ed e r i v e df r o m
similar
may h a v ep r o d u c e do t h e rP r e c a m b r i a ng r a n i t e s
i n New M e x i c o .
D i f f e r e n c eisd
n e p t hosef m p l a c e m e nottfh ge r a n i t i c
r o c k se x p o s e di nt h eL e m i t a rM o u n t a i n s
may a c c o u n t for t h e
h e t e r o g e n e i t sye e nT. h be i o t i t ge r a n i t e
is
at
emplaced
a
t h o u g httb
oe
its
relative
sh
l ya l ldoewp
dt tu
ohe
f i n e - g r a i n e da n dp o r p h y r i t i cn a t u r ea n d
its
s i m i l a r i t yt o
i n t h eD i x o n - P e n n a s c o
t h eP u n t i g u d og r a n i t ep o r p h y r y
a l s o t h o u g h t ob ee m p l a c e d
at 2
-
4 km.
(Long, 1974).
area,
The
Cine-grainedp
, o r p h y r i t i cm u s c o v i t e - b i o t i t eg r a n i t ei s . a l s o
t h o u g htbtoeem p l a c e d
at
shallod
we p t hbse c a u soef
d i s c o r d a n tr e l a t i o n s h i p -w i t ht h eC o r k s c r e w
( B u d d i n g t o n , 1959).
its
C a n y o ns e q u e n c e
H o w e v e trh,me i g m i t i z a t i oanl o nt gh e
is
i n t r u s icvoen t w
a ctL
ih
ttehem i dt ai or r i t e / g a b b r o
s u g g e s t i v eo fd e e p e rd e p t h so fe m p l a c e m e n t h a nt h eb i o t i t e
granite
(2
-6 km.).
T h e a b u n d a n c eo pf e g r n a t i t e tsh r o u g h o u t
t h eP o l v a d e r ag r a n i t es u g g e s dt e e p e d
r e p t h so ef m p l a c e m e n t
( > 6 k m . ) .P e g m a t i t e sa r er a r e
6 km.) a n tdh o sfee w
pegmatites
s h a l l o wd e p t h sa r ec h a r a c t e r i z e d
absent i n
s a n i d i n ea,nadr e
is
gneissig
cranite
d e e pd e p t h s ,
6
-
i n t h ee p i z o n e( d e p t h so f
known
h a vfeo r m e d
at
b yb i - p y r a m i d a lq u a r t za n d
t hLee m i t apre g m a t i t e sT.h e
t h o u g ht tboeem p l a c e d
1 3 k m .d, u e
t o
2
at relatively
t o i t s c o n c o r d a n tr e l a t i o n s h i p
w i tthhCe o r k s c r e w
C a n y osne q u e n c ee,v i d e n coef fo r c e f u l
sediments),
i n j ied(ncittk
thrieiu
ton
shdnei n g
c o a r s e - g r a i n e ds i z e ,a n ds i m i l a r i t yw i t ht h eP e n n a s c oq u a r t z
at 8
m o n z o n i t e( a l s oe m p l a c e d
and
others
-
(1975) p r o p o s e d
1974).
1 3 km.,Long,
Barker
a m o d efl o trh eo r i g i no tfh e
i s s i m i l a r i n c o m p o s i t i o nt ot h e
P i k e sP e a kg r a n i t e w
, hich
was
L e m i t a r g r a n i t e s ,s u g g e s t i n gt h a tt h eP i k e sP e a kg r a n i t e
e m p l a c e d a t d e p t hos f
3
-
7 km.
well
e m p l a c e m ecnot r r e l a t e s
T h irsa n g e
withe
in
2
-
d e p t .ho f
8 km.
range
d e t e r m i n e df o rt h eP r e c a m b r i a ng r a n i t e se x p o s e di nn o r t h e r n
N e w M e x i c o( L o n g ,
1 9 7 4 ) a n d i n t h e Lemitar M o u n t a i n s .
CARBONATITE DIKES
Introduction
Carbonatites
are
1966).
c a r b o( nHaet ien r i c h ,
rauhaugite
(>80%
>50%
i g n e oruoscckosn s i s t i on fg
Sovite
(>80% c a l c i t e ) ,
1,
d o l o amnaidtn/eko er r i t e
and
s i l i c o c a r b o n a t i t e ( 5 0 - 8 0 % c a r b o n a t es p e c i e s )d i k e sa n dv e i n s
o c c ut h
r r o u g h o ut htm
eapped
rockstothenorthinthe
area
and
in
Lemitar Mountains.
the
Precambrian
Distribution
T h ec a r b o n a t i t ed i k e ss t r i k ed o m i n a n t l yn o r t h - s o u t h
e a s t - w e s ta n dd i ps t e e p l y
(Pl.
or
1 9 a n d 2 0 ) a n d c r o s s c u tt h e
e n t i rPe r e c a m b r i asne q u e n c eT. hdei k ersa n gietnh i c k n e s s
from
a
few
cm.
to
a
d i s c o n t i n u o uds uteeor o s i o nh, o w e v e r
m
f eewt eMrdsoi.askrtees
a
few
dikes
can
be
TABLE
a
MINERALS OF CARBONATITE COMPLEXES
LOCALITY
MINERALS
Mountain Pass,
California
c a l c i t e ,d o l o m i t e ,a n k e r i t e ,s i d e r i t e ,
b a s t n a e s i t e ,q u a r t z ,p h l o g o p i t e ,b i o t i t e ,
a l l a n i t e ,m a g n e t i t e ,h e m a t i t e ,g a l e n a ,
a n d o t h e rm i n e r a l s
p y r i t e ,f l u o r i t e ,
i n c l u d i n gs e v e r a ls u l p h i d e s
Iron H i l l ,
Colorado
d o l o m i t e ,c a l c i t e ,a p a t i t e ,l i m o n i t e ,
a e g i r i n e ,s o d aa m p h i b o l e ,p h l o g o p i t e ,
m i c r o c l i n e ,q u a r t z ,f l u o r i t e ,s u l p h i d e s ,
p y r i t e ,a n do t h e rm i n e r a l s
MagnetCove,
Arkan'sas
c a l c i t e ,d o l o m i t e ,a n k e r i t e ,m i c r o c l i n e ,
a p a t i t e ,m a g n e t i t e ,p h l o g o p i t e ,a n d
others
AlnoIsland,
Sweden
c a l c i t e ,d o l o m i t e ,a n k e r i t e ,b i o t i t e ,
p y r o x e n e ,q u a r t z ,p y r i t e ,a l b i t e ,
g a r n e t ,c h l o r i t e ,b a r i t e ,a p a t i t e ,
f l u o r i t e ,a n do t h e r s
F e n ,N o r w a y
s o v i t e - c a l c i t e ,b i o t i t e ,a p , a t i t e ,
m a n g a n o p h y l l i t e ,m i c r o l i t e
r a u h a u g i t e - c a r b o n a t e s ,a p a t i t e ,b i o t i t e ,
Wet M o u n t a i n s ,
Colorado
c a l c i t e ,d o l o m i t e ,b a r i t e ,b a s t n a e s i t e ,
b i o t i t e ,p h l o g o p i t e ,a p a t i t e ,g a r n e t ,
g a l e n a ,s p h a l e r i t e ,q u a r t z ,z i r c o n ,
and o t h e rm i n e r a l s
Lemitar
Mountains,
New Mexico
c a l c i t ed, o l o m i t ea, n k e r i t eb, a r i t e ,
b a s t n a e s i t e ,b i o t i t e ,p h l o g o p i t e ,
f l u o r i t e ,m i c a s ,a p a t i t e ,g a r n e t ,z i r c o n ,
q u a r t z ,m a g n e t i t e ,a n dm i c r o c l i n e
Page 79
TABLE 9
CHEMISTRY OF CARBONATITES
Si02
Ti02
A1203
Fe203
FeO
MgO
CaO
Na20
K20
MnO
~ 2 0 5
c02
TOTAL
1
2
3
4
5
6
7
-
-
-
1
2
3
4
5
6
13.87
0.48
24.16
3.40
0.28
0.50
3.04
10.30
0.73
3.29
14.96
1.10
1.32
20.65
0.47
4.32
3.46
6.53
1.91
11.75
7-05
3.60
3.13
8.92
5.79
7.04
30.4
2.28
9.47
2. 8 8
3.39
4.80
9 - 56
29.9
0.37
0.63
0.64
3.44
26.77
96.73
1.78
4.95
7.68
6.87
6.80
17.2
0.75
1.51
0.35
1.32
17.77
91.14
28.7
0.01
0.10
0.48
0.06
35.80
36.1
2.09
28.52
0.36
2.33
26.81
95-56
91.17
97 70
0.42
1.36
0.68
1.44
-
20.33
0.24
2. 0 8
1.30
1.97
26.25
97-91
a v e r a g ep r i m a r ym a g m a t i cc a r b o n a t i t e ,L e m i t a rM o u n t a i n s
a v e r a g er e p l a c e m e n t - t y p ec a r b o n a t i t e ,L e m i t a rM o u n t a i n s
a v e r a g ea n k e r i t i cc a r b o n a t i t e ,
Lemitar Mountains
a v e r a g ec a r b o n a t i t e ,H e i n r i c h ,
1966
r a u h a u g i t e ,I r o n
H i l l , C o l o r a d o ,N a s h ,
1971
b i o t i t e ,a n k e r i t i c - d o l o m i t i cc a r b o n a t i t eb r e c c i a ,
C a s t i g o nL a k e ,C a n a d a ,C u r r i e ,
1976
a v e r a g el i m e s t o n e ,P e t t i j o h n ,
1957
P a g e 80
TABLE 1 0
TRACE
ELEMENT
1
1294
297
44
Ba
Sr
N i
cu
co
Cr
L i
Zn
13
36
16
36
133
U
1
2
3
4
5
6
7
8
8.7
-
-
CHEMISTRY
OF
CARBONATITES
2
3
4
2 4 9 0 2155
450-1120
130
355
286
59
8
63
13
2.5
64
54
17
2314 8
15
40
7
275
527
8.4
4.7
5
830
3200
6
1000
3000
85
5i
nil
nil-13
8
109
40
7
8
5300
15000
880
3200
200
51
43
39
110
470
470
110
5
26
a v e r a g e p r i m a r ym a g m a t i cc a r b o n a t i t e ,L e m i t a rM o u n t a i n s
a v e r a g e r e p l a c e m e n t - t y p ec a r b o n a t i t e ,L e m i t a rM o u n t a i n s
a v e r a g e a n k e r i t i cc a r b o n a t i t e ,L e m i t a rM o u n t a i n s
a v e r a g e c a r b o n a t i t e ,H e i n r i c h ,
1966
a v e r a g e of 4 s o v i t e s ,S o k l i ,F i n l a n d ,V a r t i a i n e na n d
Woolley, 1976
c a r b o n a t i t e ,M a g n e tC o v e ,A r k a n s a s ,E r i c k s o n
and Blade,
1963
p r i m a r ym a g m a t i c ,
Wet M o u n t a i n s ,C o l o r a d o ,
A r m b r u s t m a c h e r , 1979
r e p l a c e m e n t , Wet M o u n t a i n s ,C o l o r a d o ,A r m b r u s t m a c h e r ,
1979
TABLE 11
SIMILARITIES AND DIFFERENCES BETWEEN THE LEMITAR
C A R B O N A T I T E AND OTHER CARBONATITES
SIMILARITIES
A.
Occurrence
N o n a l k ai gl incecooum
s p leexxa,m p R
l easv: C
a lolui n t y ,
M o n t a nVae; r i B
t yr,i t iCs o
h l u m bC
i aa,n a dSaa;l mB
o any ,
A l a s k aT; u rPi e n i n s u l a ,
U.S.S.R.;
(Heinrich, 1966).
Transvaal
M a af iscs o c i a t i oenx,a m p l e s :
M a g nHeet i g h t s ,
1
9
6
6
)
,
V
e
r
w
o
e
r
d
,
( g a b b rmo a, g n e t i tael ,b i t i t e ,
Stjernoy,
Norway
( g aV
b be r o
w,o e r d ,
1966);
Sokli,
Finland,
( a m p h i b o l i t eV
, artiainen
and
Woolley,
1 9 7 6 1 , M e s s u mS,o u t h
1966).
West A f r i c a( b a s a l t ,d o l e r i t e ,g a b b r o ,V e r w o e r d ,
S t r u c t u r ea n dT e x t u r e
R e p l a c e m ecnatr b o n a t i t e s
common,
example:
Wet M o u n t a i n s ,
C o l o(rAa rdm
o brustmacher,
1979);
S i i l i n j a er v
a si ,t e r n
F i n l a n d( P u u s t i n e n ,
1969).
P o r p h y r i tt iecx t u r e s
common,
example:
1979).
C o l o r a d o( A r m b r u s t m a c h e r ,
x e n o l i tw
h is t htcihnaer b o n a t idtiek e s ,
O c c u r r e n c e of
examples :
M o u nP
t aC
aisansl ,i f o r M
n i aa t; o p o n
N y a s a l a n dP; a n d a
Hill, T a n g a n y i k a( H e i n r i c h ,
Sligh
f ot l i a t i opna r a l l te o
hl e
walls
e x a m p l e sM
: o u n t a iPn a s sC, a l i f o r n i(aO l s o ne,t
Wet M o u n t a i n s ,C o l o r a d o( H e i n r i c h ,
1966).
P r e s e n c e o f z o n i n gw i t h i n
M o u n t a i nP a s s ,C a l i f o r n i a
C.
Wet
Hill,
1966).
toh
dfe
ikes,
al.
tchaer b o n a t idtiekeex,a m p l e :
(Heinrich, 1966).
Mineralogy
Common m i n e r a l o g y( t a b l e
Mountains,
8
L a c ko f e l d s p a t h o i d sa n ds o d aa m p h i b o l e s e, x a m p l e M
: ountain
P a s s ,C a l i f o r n i a( O l s o n ,e t
al., 1954).
1954);
P a g e8 2
TABLE 11
D.
-
continued
Alteration
(10) F e n i t i z a t i o n , i f p r e s e n t ,
i s p o o rdl ye v e l o p eedx, a m p l e s :
Magnet H e i g h t s , T r a n s v a a l ( V e r w o e r d1, 9 6 6 )S; o k l iF, i n l a n d
( V a r t i a i n e n a n dW o o l l e y , 1 9 7 6 ) .
DIFFERENCES
A.
Occurrence
(1) A b s e n cor ef l a t eadl k a l ri o
c c k es x, a m p l e F
s :e n ,
( H e i n r i c h , 1966);
Norway
A l n oS, w e d e n
(von
Eckermann,
1948).
(L
2 )a cao k
sf s o c i a t el ad r g e
mass o
p rl u g
of
carbonatite,
e x a m p l e sM
: ountain
P a s s , C a l i f o r n i (a O l s o ne, t . a l . ,
1954);
A l n oS
, weden
(vori Eckermann, 1 9 4 8 ) .
( 3 ) No a s s o c i a t e dk i m b e r l i t e sw h i c ha r eo f t e n b, u nt o at l w a y s ,
a s s o c i aw
tceiad
t rhb o n a ct iot m
e p l e xeexsa, m p lFeesn: ,
N o r w a syo; u t h w eTs ta n g a n y i kG
a ;i b e opnr o v i n cSe o
, uth-West
Africa ( H e i n r i c h , 1966).
B.
Mineralogy
( 4 ) A p p a r e n tl a c k
o f s u l p h i d em i n e r a l s
common t oo t h e rc o m p l e x e s
(table 2).
( 5 ) L a c k of f e l d s p a t h o i d s a n d s o daam p h i b o l e se ,x a m p l e sF:e n ,
Norway
(Heinrich,
1966);
A lSnw
o ,e (dE
veocnn
kermann,
1948).
C.
Alteration
( 6 ) Absence of
l a r gh ea l o
Sweden ( v o nE c k e r m a n n ,
foef n i t i z a t i o n ,
Alno,
examples:
F e n , Norway ( H e i n r i c h , 1 9 6 6 ) .
1948);
P a g e 83
TABLE 1 2
X-RAY
FROM THE LEMITAR MOUNTAINS
DIFFRACTION LINES OF BASTNAESITE
hkl
Lem 5 0 0
d
d
I
4.84
40
4.88
40
110
3.54
60
3.56
70
112
2.89
100
2.88
100
114
2.02
60
2.02
40
202
2.62
40
2.61
20
300
2.09
60
40
2.06
302
1.90
60
-
1-90
40
h e a v ym i n e r a ls e p a r a t ef r o mt h eL e m i t a rM o u n t a i n s
(see f i g .
-
I
002
L e m 500
PDF
PDF
2 f o rs a m p l el o c a t i o n )
P o w d e rD i f f r a c t i o nF i l e( 1 9 7 2 1 ,c a r d
C h e m i c a lf o r m u l ao fb a s t n a e s i t e
i s CeC03F
11-340
PL.
19:
B r e c c i as i l i c o c a r b o n a t i t ed i k ec r o s s c u t t i n g
s e d i m e n t s i n C o r k s c r e wC a n y o n( l o o k i n gn o r t h ) .
PL. 2 0 :
S t e e p l yd i p p i n gc a r b o n a t i t ed i k ei n t r u d i n gt h e
L e m i t a rd i o r i t e / g a b b r o( l o o k i n gn o r t h ,
i n sec. 7).
P a g e 85
t r a cfseoedrv e rhauln d rm
e de t earl sosntgr i kFel .o w
s t r u c t u r e s o r b a n d i n go f t e np a r a l l e l ts h ec o n t a c t o
s tf h e
d i k (ePs211. ) .
Some d i k ef o
s l l opwr e - e x i s t i nf gr a c t u r e
z o n e sF. e e d e sr y s t e m o
s ften
main
f i l l f r a c t u r e sa d j a c e n t ot h e
d i kT
e .hr ea n d oomr i e n t a t i o n
o f t hdei k e s
(Map 1)
s u g g e s t st h a t h ec a r b o n a t i t ef l u i d sf o l l o w e dp r e - e x i s t i n g
f r a c t u r ez o n e s
i n t h ed i o r i t e / g a b b r o ,t h es e d i m e n t s ,a n dt h e
P o l v a d e rGa r a n i t eO. f t etnhcea r b o n a t i tfel u i df so l l o w e d
e a r l i e rm a f i cd i k e s ,p a r t i a l l y
o r c o m p l e t e l yr e p l a c i n gt h e m ,
a s d i s c u s s e d e a r l i e r ( s e eM a f i cD i k e s ) .
A p p a r e n t l y ,f r a c t u r e sw e r er a r ei nt h eg r a n i t i cr . o c k s ,
a s a b u n d a nw
t ithin
b e c a u s et h i c kc a r b o n a t i t ed i k e sa r en o t
tghrea n i t e
as
t hw
a eriy
et d
h
t hi o
n
erite/gabbro.
C a r b o n a t i t ed i k e sa r en o ot f t e nf o u n dw i t h i nt h eb i o t i t e ,
muscovite-biotite,
o r g n e i s s i cg r a n i t e s ,e x c e p to c c a s i o n a l l y
a l oti nh
n get r u s icvoen t a cTtcsha.er b o n a tfi lt ue i d s
a
g e n e r asl hl ya t t e rP
th
eod
el v a d G
e rraa n iftoer, m i n g
s t o c k w o r kp a t t e r n .
C a r b o n a t i t ed i k e sa r er a r e
a r e aT
. his
i n t h es o u t h e r nt h i r d
may s u g g e s t h a t h es o u r c e
t h ea r e an o r t ho fC o r k s c r e w
71, w h e r et h ef r e q u e n c y
of t h e
may b ec e n t e r e d
Canyon ( n o r t h e r n p o r t i o n o f s e c .
of c a r b o n a t i t ed i k e s
is greater.
in
PL.
21:
B a n d e ds i l i c o c a r b o n a t i t ed i k e .
Page 87
Description
One of
in
t hc eh a r a c t e r i s t i co
c sa
f rbonatites
the
L e m i t a r Mountains i s t h ep e t r o l o g i cv a r i a t i o n st h e ye x h i b i t .
T hdei k evsa r y
i n m i n e r a l o g(yf i g .
s i z e ,t e x t u r e ,
a n d c h e m i s t r y( A p p e n d i x
i n the
t h e c a r b o n a t i t ees x p o s e d
can
Mountains
be
a s ptroi m amr ya g m a at rinecdp l a c e m e n t
differentiated
1979).
c a r b o n a t i t e s( A r m b r u s t m a c h e r ,
(table
grain
I nt h i ns e c t i o n ,
C).
Lemitar
131,
table
13,
1 31
are
T e x t u r ea n dm i n e r a l o g y
criteria
p tr h
im
e ary
tfhoi rs
d i f f e r e n t i a t iPorni .mcaarryb o n a t ei txehs i ibgi nt .e o u s
poor r pp rhi ymr aietriiytch
ex
e rt u r e s ,
h y p i d i o m o r p h i c - g r a n(uplla. r
carbonatites
are
22).
characterized
by
and
a p a tm
i taeg, n e tfiet led, s p a r ,
are
R e p l a c e m ecnatr b o n a t i t e s
P r i mp ao rr yp h y r i t i c
l a rp
gh
e e n o c r y sot fs
biotite/phlogopite.
characterized
or
c o a r s e - g r a i n e dc a r b o n a t ep a r t i a l l y
by
fine-
or
completely
replacing
r e l i c t p h e n o c r y s t so ff e l d s p a ra n d / o rh o r n b l e n d e ,p r e s e r v i n g
t h oe r i g i n atle x t u r e s
o f t hreo c(kp l .
were
o r irgoi cnka sl
in
and
24).
The
d
m
girakafen
ioscir,t e s ,
d i o r i t e / g a b b r o , a s i n d i c a t e db y
m o raeb u n d a n t
23
r e l i c t t e x t u r e s .A p a t i t e
is
t h e primarm
y a g m a t i c a r b o n a t i t e sw
, hile
m a g n e t i t e i s m o r ea b u n d a n t
a l t h o u gbho at hp a t i at enmda g n e t i t e
i n t h er e p l a c e m e n tc a r b o n a t i t e s ,
may
bp er e s e n t
in
CARBONATES
50
APATITE
50
MAGNETITE
LEMITAR
MOUNTAINS
0 P R I M A R YC A R B O N A T I T ED I K E S
X
R E P L A C E M E N TC A R B O N A T I T ED I K E S
ALNO, SWEDEN (von ECKERMANN,1948)
0
SOVITES
S O K L I , F I N L A N D ( V A R T I A I N E NAND WOOLLEY, 1976)
A AVERAGESOVITE
A
A V E R A G ER A U H A U G I T E
FI GURE 13:
CARBONATE-APATITE-MAGNETITE PLOT OF THELEM ITAR
CARBONATITES
TABLE 13
MINERALOGY OF CARBONATITES OF THE LEMITAR MOUNTAINS
MINERAL
ABUNDANCE
PRIMARY MAGMATIC
Ankerite
Apat i.te
Barite
Bastnaesite
Biotite/phlogopite
Calcite
Chlorite
Dolomite
Fluorite
Garnet
Hematitelgoethite
Hornblende
Ilmenite
K-feldspar
Magnetite
Muscovite/sericite
Plagioclase
Pyrite
Pyrochlore
Sphene/leucoxene
Quartz
Zircon
E
R
-
-
essential to all samples, C
present in a few samples, -
REPLACEMENT
c ,E
E
R
R
C
E
R
E
C
R
R
C
E
R
C
C
C
R
C
R
-
-
present in most samples,
not present
PL. 2 2 :
P h o t o m i c r o g r a p h (25x, c r o s s - p o l a r s o
)f
p o r p h y r i t icca r b o n a t i t e .
a
A t t hbeo t t o m
a r o c kf r a g m e n t .
of t h e photograph is p a r to f
.
H
0.3 mm
PL.
23:
Photomicrograph
( 2 5 xp, l a n lei g h t )
of a
r e p l a c e m e n tc a r b o n a t i t e ,p r e s e r v i n gt h eo r i g i n a l
p o r p h y r i t ti ec x t u r e .
PL.
24:
Photomicrograph
( 2 5 xp, l a n lei g h t )
of
a
r e p l a c e m e n tc a r b o n a t i t ep r e s e r v i n gt h eo r i g i n a l
ophitictexture.
P a g e9 2
i s i n a d e q u a t ei nt h ef i e l da n d
e i t h e r .T h i sc l a s s i f i c a t i o n
furtheg
r r o u p i n g sa c c o r d i n gt om i n e r a l o g ya n dt e x t u r ea r e
necessary.
T h ec a r b o n a t i t ed i k e s
b r o a d l yc h a r a c t e r i z e d
i n t h e L e m i t a r M o u n t a i n sc a nb e
as d i k e sc o n t a i n i n gx e n o l i t h s( b r e c c i a
a n dm i c r o b r e c c i as i l i c o c a r b o n a t i t ed i k e s )a n dt h o s ew i t h o u t
x e n o l i t h sT. hber e c c iaanm
d i c r o b r e c c isai l i c o c a r b o n a t i t e
d i k e s are l i g h t t o
m e d i u m - g r a y ,w e a t h e r i n g
magmatic.
a n dg e n e r a l l yp r i m a r y
t o a d i r t yb r o w n ,
10
T h ed i k e sc o n s i s ot f
40% x e n o l i t h s( r o c kf r a g m e n t s a) n d> 6 0 %c a r b o n a t i t e
matrix
(up
( p l2.a5n2d6 )L. a r gpeh e n o c r y s t so,f t em
n egascopic
ts oe v e r a l
mm.
-
a c r o sm
so)fa, g n e t i t e
(5-10%),
apatite
(5-10$)b
, i o t i t e / p h l o g o p i t e( 5 - 1 5 $ ) a, n df e l d s p a r( < 2 $ )a r e
a
f o u n ds c a t t e r e dt h r o u g h o u t f, o r m i n g
p o r p h y r i t i ct e x t u r e .
Othem
r i n e r a l so c c u tr h r o u g h o u tt h ef i n e - g r a i n e dc a r b o n a t e
m a t r i x ( t a b l e 13).
O f t etnh e sm
e i n e r a lasrceo r r o d e d
of
c r raeaccpn
kald
erbab
dy
coenR
daetseo. r p t i o n
phenocrysts
is
common.
On
a
w e a t h e rs eudr f at h
cese
p h e n o c r y s t so f t e ns t a n do u tw h e r et h ec a r b o n a t e
d i s s o l v e d away.
t hdei k e
(pl.
or
S o v i t ea n dr a u h a u g i t ev e i n so f t e nc r o s s c u t
2 6T
) .hcea r b o n a t i tdei k eosf t ecnr o s s c u t
e a r l i e r -mafic d i k e s (pl.
27).
matrix has
PL. 25:
Breccia silicocarbonatite
d i k e (sample Lem 5 0 0 ) .
P e n c i l is a p p r o x i m a t e l y 20 cm. long.
PL. 26:
P h o t o m i c r o g r a p h ( 2 5 x , cross-polars) of a s o v i t e o r
rauhaugite vein crosscutting a replacement
carbonatite. The vein
PL. 27:
is 0.7mm
thick.
Breccia silicocarbonatite dike (brown)
crosscutting diorite/gabbro (lighter gray) and
mafic dike (darker gray, fine-grained).
a
I”--)
0.3mm
X e n o l i t hvsa r y
i n s i zf er o m
a
mm.
few
to
a
meter
a c r oXs es n o l i tihnsc l ufdr ea g m etn
hohtofreso
s tc k ,
f o l i a t e gd r a n i t e sf ,o l i a t e adr k o s e sq, u a r t z i t e sg, r a ayn d
g r e esnc h i s pt ,h y l l i t e sa ,nrdegdr a n i t if ce n i t e s .
g r a n i t i cx e n o l i t h sh a v e
texture
as
Some
s i m i l a r a p p e a r a n c e ,c o m p o s i t i o n ,a n d
t hPeo l v a d e rG
a r a n . i t ew, h i loet h e rhsa v e , b e e n
completely o r p a r t i a l l y
altered
to
a
f e n i tceo m p o s eodf
l i t t l e qnouora ra tnzd
K - f e l d s paabnrido t iwt ei t h
as a
p l a g i o c l a s e .T h ex e n o l i t h sa r eo f t e nr o u n d e d ,p o s s i b l y
r e s u lotcf h e m i c arle a c t i o nw
s i t thh ce a r b o n a t i t fel u i d s
a n d / o r a s a r e s u lot cf o l l u s i . o n w
s ith
each
o t h e ar n d
the
s u r r o u n d i n g wall rock.
C a r b o n a t i dt ei k w
e si t h o xu et n o l i t h
c asbf n
ue r t h e r
g r o u p e da c c o r d i n gt om i n e r a l o g i c a lc o m p o s i t i o n :
( 1 )f i n e - g r a i n e dd o l o m i t i ct oc a l c i t i c
s i l i c o c a r b o n a t i t ed i k e s
(2)
a n k e r i t i rc a u h a u g i t d
eikes
(3)
s o v i t ea n dr a u h a u g i t ev e i n s
( < 5 cm. t h i c k )
B o t hp r i m a r ym a g m a t i ca n dr e p l a c e m e n tt y p e sa r ef o u n dw i t h i n
t h i ns e c t i o n so ft h ev a r i o u sg r o u p i n g s .
F i n e - g r a i n eddo l o m i t itccoa l c i t isci l i c o c a r b o n a t i t e
dikes
are
lighto
g r a yB
. o t hp r i m a r ym a g m a t i c
in
m e d i u m - g r a yw, e a t h e r i ntgo
a brownish
a n d r e p l a c e m e n tv a r i e t i e so c c u r
b o t thy p e sO. f t e fni n e - g r a i n e sdi l i c o c a r b o n a t i tde i k e s
Page 96
g r a di n
e tmoa f d
i ci k e s .
One
of
occurrence
d o l o m i t it co
'7) c o n t a i n e d small
c a l c i t isci l i c o c a r b o n a t i tde i k e(ss e c .
v e i n so fm e g a s c o p i cp u r p l ef l u o r i t ea n ds u l f i d em i n e r a l s .
A n k e rriat u
i ch a u d
g ick
treeo ss sf ci nu et - g r a i n e d
28 a n d 2 9 ) .
s i l i c o c a r b o n a t i t de i k e(sp l .
l i gbhrto w n
and
consist
of
These d i k e s a r e
a n k e r i t ce a, l c i t be a, r i t e ,
d o l o m i thee,m a t i taem
n,da g n e t i tTeh. edsiekceosm m o n l y
6.
o c c u r i n a n d n o r t ho fs e c .
T sh oi nvari n
.t aedu h a u gvi et cei n
r os s s o
c tuht e r
c a r b o n a t i t ed i k e sL. a r g e sr o v i t ev e i n (s u pt os e v e r a l
t h i c k )o f t e nf o l l o wp r e - e x i s t i n gf r a c t u r e s
d i k ea snsdo m e
are
mm.
or e a r l i e r. m a f i c
h i g h lrya d i o a c t i v(eutp
1o0t0i m e s
backgroM
u nidc )r .o s c o p ircasaao
ulnv
hl dy
iat,ueg i t e
v e i n l e tcsr o s s c ut h
t cea r b o n a t i t e
m a t r i x , x e n o l i t h as n
, d
p h e n o c r y s t s .C l e a r l yt h e s ev e i n l e t sr e p r e s e n t
a l a t e rs t a g e
o fc a r b o n a t i t ei n t r u s i o n .
T h i n l, i g h b
t r o w nd i k e l e t so rv e i n s
fill
s y s t e tm
iP
hnso
e l v a d eG
r ar a n i tfeo,r m i n g
p a t t e r n (Map 1 ) .
the
fracture
a
stockwork
C a r b o n a t i t ef l u i d sa p p a r e n t l yi n t r u d e dt h e
g r a n i t ea n df o l l o w e dp r e - e x i s t i n gf r a c t u r eo rs h a t t e rz o n e s .
T h e s ev e i n sc o n s i s to fb a r i t e ,c a l c i t e ,d o l o m i t e ,a n k e r i t e ,
and
h e m a t i t eO
. r i g i n a gl r a n i t i ct e x t u r e as n dm i n e r a l as r e
o pf tr ee ns e r v
F ee dl d. s p
hbpaearversent ioa rl l y
c o m p l e t e rl y
e p l a c ebcdya r b o n a tT
e .h e smei c ah sa vbee e n
8
PL.
28:
F i n e - g r a i n e dd o l o m i t i cs i l i c o c a r b o n a t i t ed i k e
(sample Lem 5 3 0 ) c u t b y a n k e r i t i c r a u h a u g i t e
d i k e s( s a m p l e
Lem 531A a n d B ) .
approximately thirty
PL.
29:
Pistol is
cm. . l o n g .
F i n e - g r a i n e d o l o m i t i sc i l i c o c a r b o n a t i t de i k e
c u tb ya n k e r i t i cr a u h a u g i t ed i k e s .P e n c i l
. a p p r o x i m a t e l y 20 cm.
long.
is
l e f t i n t a c st ,u g g e s t i nlgo twe m p e r a t u r e s
at
t htei moef
is
difficulto
replacement.
T haegoetfhL
e e m i t acra r b o n a t i t e s
d e t e r m i n eT. e r t i a r fya u l ttsr u n c a t teh ce a r b o n a t i t de i k e s
6 (Map 1) i n d i c a t i n tgh at thcea r b o n a t i t ews e r e
isne c .
e mTpelrptaftorciaiaeuordlryF
t iunrgt .h e r m o r e ,
c a r b o n a t i t e sh a v en o b
t e e nf o u n d
i n a n yr o c k sy o u n g e rt h a n
P r tehcea m b( pr iear nsr oe n
co
a ln n a i s saanndc e
R.M.
Chamberlin
p ,e r s o n ac lo m m u n i c a t i o nT
) .hcea r b o n a t i t e s
a P e n n s y l v a n i a nf a u l t( s e c .
h a v eb e e nf a u l t e db y
may
7 , Map l),
s u g g e s t i n g a p r e - P e n n s l y v a n i a na g e .
Geochemistry
A r e p r e s e n t a t i vseu i tosefa m p l ef sr o tmhvea r i o u s
c a r b o n a t i t ed i k e s
(Appendix C ) .
was a n a l y z e df o rm a j o ra n dm i n o re l e m e n t s
A s c i n t i l l a t i ocno u n t e r
was
n oa tv a i l a b l e
d u r i nt ghsea m p l i npge r i o dt h; e r e f o r et h,sea m p l ews e r e
c o l l e c twe idt h oakunntyo w l e td
ro
hagfede i o a c t i v i t y
content.
A f e w o f t h ec a r b o n a t i t e sh a v em a j o re l e m e n to x i d e
sums l e s st h a n
100%.
T h ed i f f e r e n c ec a nb ea c c o u n t e df o rb y
n u m e r o u so t h e re l e m e n t st h a tw e r en o td e t e r m i n e d .
T h ec a r b o n a t i t ed i k e s
on
f a l l i n t ot w op o p u l a t i o n sb a s e d
9).
i r o nc o n t e n (t t a b l e
i s due
The
h i g h e irr o n
content
t tohpe r e s e n coeafn k e r i taen hd e m a t i t eT. hhe i g ihr o n
in
c a r b o n a t i tdei k easrneo t
c a r b o n a t i t ed i k e s ,
c o n t a cwt i tthhl eo iwr o n
s o t h ee x a c ta g er e l a t i o n s h i p
i s unknown.
H o w e v eerv, i d e n fcreoom
t hleorc a l i t iiensd i c a ttehsa t
a n k e r i t e i s o n oetfh e
l a s t c a r b o n a t e ts of o r m( e x a m p l e s :
E a s t eSr na y M
a no u n t a i n s ,
Iron H i l l ,
U.S.S.R.;
1966).
M o u n tPa aiCnsas l, i f o r nHi ae ;i n r i c h ,
c a l c i ucm
ontent
of
L e m i t aP
r r e c a m b r i a nr o c k s
c a r b o n a t i t e sh a v e
Colorado;
h
Tihgeh
t hc ea r b o n a t i t er es l a t i vtoo
et h e r
13..
The
as w e l l ( t a b l e
9).
i s q u i t eo b v i o u si nf i g .
a h i g hv o l a t i l ec o n t e n t
Iannpya r t i c u l ao rc c u r r e n c tehc, ea r b o n a t i t ea sr e
q u i t eh e t e r o g e n e o u m
s i n e r a l o g i c a l l ya n dc h e m i c a l l y .
t h i sh e t e r o g e n e i t y ,n o r m a lv a r i a t i o nd i a g r a m s
Due t o
commonly
used
it nhset u doiyg
f n e o ur so c kasrneov te ruys e f u l .
v a r i a t i o nd i a g r a mh a sb e e n ' u s e db y
A
Dawson ( 1 9 6 7 ) t o show t h e
c h e m i c a lr e l a t i o n s h i pb e t w e e nc a r b o n a t i t e sa n dk i m b e r l i t e s .
A
plot
of
n u m e r ocuhse m i ca anla l ycsoaefrsb o n a t i t e s
t h r o u g h o utth e
world
(misc.
d a t a c o m p i l e db yt h ea u t h o r ) ,
d e f i n e s a c a r b o n a t i t ef i e l d ,w h i c ho v e r l i e st h ea r e ab e t w e e n
a n dw i t h i nt h ek i m b e r l i t ea n dm a f i cc a r b o n a t i t ef i e l d s .
Lemitar s a m p l e sf a l ln i c e l yw i t h i nt h i sf i e l d( f i g .
The
14).
FIGURE 14: CHEMICAL
PLOTSHOWlNO
RELATIMISHIPBETWEEN
\
AND GRANITES
SOLID
CARBONATITES,
KIMBERLITES,
LINESREPRESENTFIELDSDETERUINED
BY DAWSON, 1967
DASHED LINE
REPRESENTS
FIELD
DETERMINED
BY AUTHOR FROM
MISC. ANALYSES 0 5 0 ) OF CARBONATITES FROU THRCUOHOUT THE
WRLD
0
Page 1 0 1
L
T ehm
e ci at ar rb o ncaotbcm
ietaepnsawr ietdh
9
H e i n r i c ha 'vse r acgaer b o n a t i( tt ea b l e
similar
L e m i t a cr a r b o n a t i t e as r eg r o s s l y
as
10).
The
t ot h i sa v e r a g e .
a n a v e r a g e of a n a l y s e s
T h ae v e r a g ce a r b o n a t i t re e p r e s e n t s
w i t hrao
eng
uyat r d
and
l otcoa t im
on
i n, e r a l oogry ,
h e t e r o g e n e i t yo tf h ec a r b o n a t i t e sT
. h ea v e r a g ec a r b o n a t i t e
reflect
dn
oo
e st
in
et hxet r ehmeet e r o g e n efi ot yu n d
general
c a r b o n a t i t iens
a
aenvdw
en
ithin
particular
locality.
Tdhies t r i b u t m
iooafnjaom
nrdi neol re m e n t s
in
c a r b o n a t it e s h a v e
b e e ne x a m i n e db ys e v e r a al u t h o r s( t a b l e
1 4 , O l s o ne,t .
1954;
a1
1963;
aB
n lda d e ,
d i f f e r e n c e si n
1966;
Heinrich,
it e s
a m o u n t s of c a l c i t e ,
1954;
Barber,
C a O , MgO, a n d t o t a il r o n
M o u n t acianr b o n a t
15).
al.,
R u s s eel t,
among
Erickson
1974).
the
The
Lemitar
p r o b a b l yr e f l e c dt i f f e r e n c e si nt h e
d o l o m i t e ,a n k e r i t e ,a n dm a g n e t i t e( t a b l e
K20 e x c e e d s Na20 i n a l l b u to n es a m p l e ,r e f l e c t i n gt h e
d o m i n a nm
o
c efi ac n
aKd- f e l d s poa vr pe lra g i o c l a sTe h
.e
i s r e f l e c t e db yt h ea m o u n o
t fP 2 0 5a n d
p r e s e n c eo fa p a t i t e
H20 ( i n c l u d e s F a n d C1).
carbonate
minerals
and
(Heinrich,
c o n s t i t u e n t o f b a r i t e( t a b l e
550a36n0, d,
Ba
531a).
a c c o u n tf o rt h ed i f f e r e n c e s
Sarrfeo u nid
ena r l y
1966).
Ba i s a l s o a major
15, samples
Differences
in
Lem
4 2 7aanbd,
m i n e r a l owgoyu l d
i n c h e m i c a cl o m p o s i t i o nb e t w e e n
P a g e1 0 2
TABLE
14
DISTRIBUTION OF ELEMENTS I N CARBONATITES
OXIDEIELEMENT
DISTRIBUTION
Si02
Ti02
A1203
F e 2 0 3 , FeO
MgO, C a O
Na20, IC20
MnO
Sr
Ba
U
P205
H20, F , C 1
C r , N i , Co
cu
q u a r t z f, e l d s p a r
m a g n e t i t e ,s p h e n e ,g a r n e t ,p y r o c h l o r e ,
micas
feldspar
m a g n e t i t e ,a n k e r i t e ,h . e m a t i t e
c a r b o n a t e s ,m a g n e t i t e
(MgO)
m i c a s ,f e l d s p a r
c a r b o n a t e s ,a p a t i t e
c a r b o n a t e s ,a p a t i t e
c a r b o n a t e s ,a p a t i t e ,b a r i t e
a p a t i t e ,z i r c o n ,p y r o c h l o r e ,s p h e n e ,f l u o r i t e
apatite
m i c a ,a p a t i t e ,f l u o r i t e ,b a s t n a e s i t e
p y r i t e ,m a g n e t i t e ,a p a t i t e
p y r i t e ,c a l c i t e ,n i a g n e t i t e
m a g n e t i t e ,c a l c i t e
phlogopite
Zn
Li
R e f e r e n c e s :O l s o n e, t
E r i c k s o na n dB l a d e ,
a l . , 1 9 5 4 ; R u s s e l l ,e t
1963; R e i n r i c h , 1966
al.,
1954;
TABLE 1 5
MINERALOGY OF THE LEMITAR CARBONATITES BY X-ray
427a
3M
0 5i n e r a l
531a
4 255
75
00
b3
060
Biotite
X
X
X
Chlorite
X
X
X
quartz
X
X
X
fluorite
X
X
calcite
X
X
dolomite
X
X
X
X
X
X
X
X
X
X
X
X
.x
X
X
X
X
X
X
X
X
X
X
X
X
X
X
apatite
X
X
X
X
X
X
magnetite
X
X
X
X
X
X
X'
X
bastnaesite
x
-
present
531b
X
ankerite
barite
DIFFRACTION
X
X
X
X
Page 104
Mountain
t hLe e m i t a r
c a r b o n a t i t easnodt h ecra r b o n a t i t e s
t h r o u g h o u tt h ew o r l d .
Fenitization
F e n i t i z a t i o n i s t h ea l k a l im e t a s o m a t i c 'r e p l a c e m e n t 'o f
c o u n t r ryo c kgs e n e r a l l ays s o c i a t e w
d i t thhien t r u s i o on f
c a r b o n aatlioktreac sloi m
c p l e xReosw
c. khhsi ac vh e
u n d e r cgoom
n epml e t ae s o mr ea pt ilca caeram
enedn t
a s s o c i a t e dw i t ha l k a l i n t r u s i o n sh a v eb e e nt e r m e df e n i t e s
(Heinrich,
1966).
r e c o g n i z e d( t a b l e
16).
a n dp o t a s s i u m( n o r m a l
Two
p r o c efseosnfeist i z a t ai or en
One i n v o l v e st h ea d d i t i o n
of
sodium
or s o d i cf e n i t i z a t i o n ) ,a n dt h eo t h e r
i n v oaltdvhdeeist i o n
of
p o t a s so(i u
n
pm
loyt a s s i c
fenitization).
is
Norm
sooardfl iecn i t i z a t i o n
tm
ho
est
common
alterap
t iroonca es s so c icaw
tathrieetbdho n a t i t e
as
i n t r u s i v e is nt h eL e m i t a M
r ountains,
later.
b ed i s c u s s e d
w i l l
Some p o t a s s i u mh a sb e e na d d e dt ot h ed i o r i t e l g a b b r o
i nt h ef o r mo fK - f e l d s p a r ,b u tt h i sa d d i t i o n
i s minor.
Some
r e dg r a n i t i cf e n i t e s ,c o n s i s t i n go fm i c r o c l i n ea n db i o t i t e
w i t hl i t t l eo rn oq u a r t z ,o c c u r
m
a ni dc r o b r e csci il ai c o c a r b o n a d
t iiteakex
ne h
ds i b i t
p o t a s s i cf e n i t i z a t i o n .
a s x e n o l i t h sw i t h i nb r e c c i a
Page 105
TABLE 1 6
CLASSIFICATION OF FENITES
( a f t e r V a r t i a i na n dW o o l l e y ,
1976)
EXAMPLE
FENITE TYPE
FEATURES
NORMAL or SODIC
FENITIZATION
Na a n d K a d d e d ,
a l k a l ip y r o x e n e s
a n d amphiboles
s t r o n g l ys o d i c
S o k l i ,F i n l a n d
I n t e r m e d i a t eT y p e
m a j o r Na a n d K
A l n oS
, weden
P o t a s s i ct y p e
major K ,
Amba D o n g a r ,I n d i a
Sodic .Type
-
K a d d e d ,n o
alkali
pyroxenes o r
a m p h i b o l e s ,o f t e n
phlogopite
POTASSIC
FENITIZATION
Ptoytpaes s i c
m i n o r Na
UB
g aKk
nu
dosau
n ,l y
Late Stage
F e n i t iszuaptei roinm
on
posed
K fenitization
n o r m a lf e n i t i z a t i o n
C h i l w aI s l a n d ,
Nyasaland (Africa)
S o k l i ,F i n l a n d
P a g e1 0 6
A t h i nz o n eo sf o d i cf e n i t i z a t i o n
some
is
developea
dl o n g
c a r b o n a t i t ed i k e si nt h ed i o r i t e l g a b b r o T
. h i sz o n e
is
n ost e e n
e v e r y w h e r eb, uat p p e a r tso
b re e s t r i c t e d
to
the
w e s t e r ns i d e so ft h et h i c k e r
T hzeo n e
i s t w o t o t e n cm.
l a r g( u
et o
p
60
mm.
characterized
by
di ina m e t e ro)r,a n g e - p i an lkb i t e
is
is
and
is
t h i c ka n d
c r y s t a lTs .hr e d d i sc ho l o r
occurrences
m e t e r c) a r b o n a t i t ed i k e s .
((1
to
common
o t h ef er n i t e
t h o u g hthtoa vbee epnr o d u c ebdtyh e
of i r o n m o l e c u l e s o r i g i n a l l y w i t h i n
o x i d a t i o na n de x s o l u t i o n
1948, p.
t hf e l d s p al ar t t i c( ev oEnc k e r m a n n ,
o x i d a t i o n i s b e l i e v e dt ob e
2 9T)h. e
a r e s u l ot tf h ed e g a s s i n g
of
c a r b o nd i o x i d ef r o mt h ec a r b o n a t i t ei n t r u s i v e .
an
T hpel a g i o c l a sceo m p o s i t i orne f l e c t s
s o d i u mb yt h ec h a n g ef r o m
An40
-
increase
An50 t o A n 5
-
in
An15.
The
f e n i t i z e dd i o r i t e / g a b b r oa p p e a r sa l s ot oi n c r e a s es l i g h t l y
i nq u a r t za n dp e r t h i t i cK - f e l d s p a rc o n t e n t .
o ff e n i t i z a t i o n
i nS o u t h
i s r e p o r t e df r o mt h e
A similar t y p e
Messum c a r b o n a t i t e v e i n
W e sA
t f r i c aF. o usr t a g e osffe n i t i z a t i o n
can
be
distinguished at
t h il so c a l i t( yionr d eoi rn
f creasing
f e n i t i z a t i o n ,V e r w o e r d ,
(1)
1966):
i n c r e a s e i n a l b i t ec o n t e n t
( 2 )i n t r o d u c t i o no fp e r t h i t i cK - f e l d s p a r
(3)
i n t r o d u c t i o no fn e p h e l i n er e p l a c i n gp l a g i o c l a s e
w i t ha c c e s s o r ys o d a l i t ea n da n a l c i t e
P a g e1 0 7
(4)
i n c r e a s eo fo r t h o c l a s e n
, e p h e l i n e a, n d
ferrohastingsite
F e n i t i z a t i o no ft h eL e m i t a rd i o r i t e l g a b b r oa p p e a r st oh a v e
p r o g r e s s e d as f a r as s t a g e 2 of t h i s s e q u e n c e .
Two s a m p l e s o f t h fee n i t i z e d i o r i t e / g a b b r (os a m p l e s
Lem
5 3 3 , A p p e n d i x B ) w e r ea n a l y z e d
5 3 2a n d
for e i g h tm a j o r
e l e m eatm
nw
ntid
soenloerm e(nAt sp p e n d i x
p r e l i m i n a r ys t u d i e s
a
C).
show a s i g n i f i c a n ti n c r e a s e
s i g n i f i c a dn et c r e a s e
in
15).
s a m p l e( sf i g .
i n t a b l e 17.
CaO
compared
u
t on f e n i t i z e d
T h e sceh e m i c ac lh a n g easrceo n s i s t e nwt i t h
as
seen
at
S o kFl i n
, land
1976).
( V a r t i a i na n dW o o l l e y ,
i n Na20 i s r e f l e c t e db yt h ec o n v e r s i o no f
T h ei n c r e a s e
a n d e s i n ae n d
l a b o r a d i o r i t teo
a l b i t ae n d
increase
i n Na20 a n d
O t h ec rh e m i c ca h
l a n g ea srs eu m m a r i z e d
n o r ms o
a ldf ei cn i t i z a t i o n
r e l a t e dt o
may b d
eirectly
l o s s of s o d i u mb yt h ea d j a c e n ct a r b o n a t i t e T
. he
in
Na20
is
a l sr oe f l e c t ebdy
n o r m a t i v ea l b i t e( A p p e n d i x
of
t toh feo r m a t i o n
C).
an
i n c r e a si e
n
The l o s s o f C a O may
t h i cn a l c i t ve e i n cs r o s s c u t t i n tgh e
d i o r i t e / g a b b r iotnh ve i c i n i t oytfh ce a r b o n a t i t de i k e s .
Some
CaO
F e 2 0 3 may
Similar
These
may
be
m i g r a ttteohcea r b o n a t i tdei k eT. i 0a2n d
loss
chemical
t ohcer o s s c u t t i nhge m a t i tvee i n s .
trends
t h r o u g h o u tt h ew o r l d( t a b l e
are
16).
r e p o r t ef rdocm
arbonatites
bde u e
FIGURE 15:
C&-Na20-K20
FENIT1ZATION
PLOT OF THEEFFECT
ON
OF
THE LEYITARDIWITWGAQBRO,TRENDS
REPORTED BY VERWOERD, IS66 FROM BASALT AND OAEBRO NEAR
THE MESSUM CbRBONATITE,SOUTHWESTAFRICA
TABLE 17
SUMMARY OF CHEMICAL CHANGES
OF THE LEMITAR DIORITEIGABBRO D U E TO FENITIZATION
Significant increase
Na20
Significant decrease
CaO
Slight increase
A1203, MgO
Slight decrease
Ti02, Fe203
No significant trend
Si02, K20, Rb, S r
P a g e1 1 0
TABLE 18
CHEMICAL TRENDS
OF
,
FENITIZED MAFIC
ROCKS
COMPLEX
FENITIZED ROCKS
REF.
LOSSES
GAINS
Messum,
b a s a ldt o, l e r i t e ,
gabbro
S.W.
Africa
Na, A l , K
B r emi v
F
e itek
a, g
b ao bt nb,r o
Norway
Mu
K h i b i n a ; - K odl iaa b a s e
S o v i e tU n i o n
M b o z i , S.W.
Tanzania
gabbro
Blu
Meo u n t a ianm
, phibolite
Ontario
Callander Bay,
a m p h iOb no tl ai tr ei o
2
3
4
-
Na,
K,
Si
K,
V e r w o e r d , 1966
R o b i n sa n dT y s s e l a n d ,
1979
C u r r i e a n dF e r g u s o n ,1 9 7 2
T h i s report
Al,
Na, A 1
g a r nSei t,
L e m i t da ir o, r i t e / g a b b r o
New Mexico
1
K , Na, Mg,
Fe, A l , T i
f o l l o w e db y
K , Na, A l ,
Si
Al,
S i , Ca,
1
A1
2
Ca, S i
2
Ca, Mg, F e
Ti
Ca, Mg, F e , 2
. .
Ti
Ca,
Na,
Fe
Mg, F e
2
T i , Mg, C a
3
K
Na,
Al,
Mg
Ca,
T i , Fe ' 4
P a g e 111
,
F e n i tan
earsoel tw apyrso d u ctL
ih
ened m i t a r
diorite/gabbro
when
a d j a c cetanort b o n a t idtiek e s .
At
a s o v i t de i k ien t r u d e gs a b b r o ,
M a g n eHt e i g h t sT, r a n s v a a l ,
m a g n e t i taean,ldb i t iwt eiantpohp a r efne tn i t i z a t i o n
(Verwoerd, 1966).
a l t e r e dt o
a n h o r n b l e n d i t e b yg a s e o u s
Fenitization is also
a t S o k l i ,F i n l a n d( V a r t i a i n e n
a b s e n tw i t h i nt h ea m p h i b o l i t e
1976).
g a b b rhoabse e n
H20 a n d C02 e r u p t i n g
1966).
f r o mt h ec a r b o n a t i t e( V e r w o e r d ,
a nW
doolley,
a
A t S t j e r n o yN, o r w a y ,
Fenitization
in
p o o r ldye v e l o p e d
is
c o u n rt or ycs k
u sr r o u n d iS
tn
hi g
ei l i n j a cr av ri b o n a t i t e
is
c o m p l eFxi ,n l a nadn,d
c h a r a c t e r i z lbeiy
dgghrte e n
1969).
a l k a l i - a m p h i b o l e sa n db l u i s hq u a r t z( P u u s t i n e n ,
T h ea p p a r e n tl a c ko fe v i d e n c ef o rf e n i t i z a t i o no ft h e
Lemitar
diorite/gabbro
c o m b i n a t i o no ft h e s e
is
probably
a
reso
u fl t
some
factors:
s t a b i l i t y of h o r n b l e n d e
(resists f e n i t i z a t i o n )
l a c ko fc o n d u i t sf o rf e n i t i z i n gf l u i d s
i n s u f f i c i e n tv o l a t i l ec o n t e n t
(H20, C02) o ft h e
carbonatitetoinitiatefenitization
i n s u f f i c i e n tp r e s s u r e sa n dt e m p e r a t u r e so ft h e
c a r b o n a t i t e st oi n i t i a t ef e n i t i z a t i o n
c o m p o s i t i o no ft h e
Lemitar d i o r i t e / g a b b r o i s
incompatiblewithfenitization
q u i c kc o o l i n g
a n d c r y s t a l l i z a t i o n of t h e
P a g e 112
c a r b o n a t i t ed i k e s ,a l l o w i n gi n s u f f i c i e n tt i m e
forfenitizationtooccur
(7)
d i s t a n c e f r o m t h es o u r c eo ft h ec a r b o n a t i t e
dikes is great.
V a r t i a i n e na n dW o o l l e y( 1 9 7 6 )s u g g e s t
fenltes
at
resists
a l t e r a t i oanntdhlea cokf
as
f r a c t u r ae n
sv de i n l e tw
s ,h i ca hc t
f e n i t i z i n gf l u i d s T
. his
of
may b e a r e s u l to ft h es t a b i l i t y
S o k l i ,F i n l a n d
o
h fo r n b l e n dweh i c h
t h a t t h el a c k
a
p a ft h
o
t hr e
may p a r t i a l l ye x p l a i nt h el a c ko f
f e n i ttieh
L
nsee m i t M
a ro u n t a i nFs e. n i t i z a t i tohnf e
c o u n t r yr o c k
i s d e p e n d e n to nv o l a t i l ec o n t e n t ,p r e s s u r e ,a n d
t e m p e r a t u r oetfh ce a r b o n a t i t e ;
g r e a te n o u g h ,f e n i t i z a t i o n
i f t h e s fea c t o r as r ne o t ,
may n o to c c u r ,
a s i nt h eL e m i t a r
M o u n t a i n sU. n f o r t u n a t e l ye,x p e r i m e n t aelv i d e n c e
t os u b s t a n t i a t et h i st h e o r y .
rock
is lacking
T h ec o m p o s i t i o no ft h ec o u n t r y
a f f e c t s t h ef e n i t i z a t i o np r o c e s s .T h el a c ko f
alkalis
effects
w o u l dp a r t i a l l ye x p l a i nt h ea b s e n c eo ff e n i t i z a t i o n
( V e r w o e r d , 19661, a n d it h a s a l r e a d y b e e n m e n t i o n e d t h a t t h e
s t a b i l i t y o f h o r n b l e n d e i s s u c h a s t or e s i s tf e n i t i z a t i o n .
If
t h ec a r b o n a t i t ed i k e sc o o la n dc r y s t a l l i z eq u i c k l y ,t h e
t e m p e r a t u r ea n dp r e s s u r ew o u l dd r o p
time
off, n o ta l l o w i n ge n o u g h
f ofre n i t i z a t i o tntoa k pe l a c eF. u r t h e r m o r e ,
as t h e
d i s t a nf cr tcoehamer b o n a tsi ot eu rbceec o ml ae rs g e r ,
f e n i t i z a t i o nb e c o m e sl e s sp r o n o u n c e d T
. his
was o b s e r v e d a t
P a g e 113
19481, a n d
A l n oS,w e d e(nv oEnc k e r m a n n ,
may
be
a
primary
r e a s o nf o rt h el a c ko ff e n i t e si nt h eL e m i t a rM o u n t a i n s .
in
T heef f e c tofsfe n i t i z a t i ohna vbee em
n inor
P o l v a d eG
r ar a n i t e
and
t hs e d i m e n t s .
c a r b o n a t ev e i n sa r ep r e s e n ta n d
stages
of
the
Some h e m a t iat en d
may b e r e l a t e d t o t h e e a r l y
a n i n c r e a siepn l a g i o c l a s e
f e n i t i z a t i o nO. f t e n
a n dK - f e l d s p a rc a nb ed e t e c t e di nt h er o c k sa d j a c e n tt ot h e
c a r b o n a t idtiek eTsPh. oe l v a d eGr ar a n iotfetbe enc o m e s
b r e c c i a t ea dnf d
r a c t u r e fdo, r m i nogn v
l ye i n l e o
tt hsf e
* c a r b o n a t i t e a n d c r e a t e s a s t o c k w o r kp a t t e r n .
at
o
f ef n i t i z a t i oonc c u r s
Callander
Bay.,
C a n a dwah, e r e
a s f o l l o w s( C u r r i e
f e n i t i z a t i o no fg r a n i t i cr o c k sp r o g r e s s e s
a n dF e r g u s o n ,
A similar t y p e
1971):
(1) h e m a t i t ev e i n s
(first stage)
(2)
i n c r e a s e i n t h eo r d e r i n go fK - f e l d s p a r
(3)
p l a g i o c l a s ec o n v e r t e dt oa l b i t e
(4)
K - f e l d s p a rc o n v e r t e dt o
p y r o x e n e sb e c o m ea b u n d a n t
plus c a l c i t e
maximum m i c r o c l i n e ,
(final stage).
T h ep r e s e n c eo fh e m a t i t e - c a r b o n a t ev e i n sa n dt h ei n c r e a s e
p l a g i o c l a s ea n dK - f e l d s p a rc o n t e n t s
i n t h eL e m i t a rg r a n i t e s
a n ds e d i m e n t si n d i c a t e st h a tf e n i t i z a t i o nh a so c c u r r e d ,b u t
h a sp r o g r e s s e do n l yt o
first stage.
in
Page
m i l l i m e t e r s ) h e m a t i t ev e i n so c c u rw i t h i n
T h i n( s e v e r a l
as c o a t i n g as l o n fgr a c t u r ae n d
t hP
e r e c a m b r i a rno c k as n d
j o i n st u r f a c e s .
114
a r e o f t e dn i s c o n t i n u o uw
s ith
T hvee i n s
l a t e r a le x t e n to fa b o u t
a meter.
a
I n t h i ns e c t i o n ,h e m a t i t e
o f t e n o c c u r sa r o u n dc o r r o d e dm a g n e t i t ea n db i o t i t ec r y s t a l s .
T h em a j o r i t yo ft h i st y p eo fa l t e r a t i o n
i s a r e s u l t of t h e
w e a t h e r i no
i rgfo n - r i cmhi n e r a las l, t h o u g h
some
may
be
r e l a t eo
to
dx i d a t i opnr o d u c ebtdh
ydee g a s s i no
tg
hf e
c a r b o n a t i t ei n t r u s i v e .
Origin
T h ec a r b o n a t i t ed i k e sw e r ep r o b a b l ye m p l a c e d
a t a great
as
d i s t a n c( el a t e r a l lovyre r t i c a l l yf r) o tm
hs eo u r c e ,
e v i d e n c e db y :
( 1 )t h el a c k
o f a n yr a d i a l
o r c o n i c a lp a t t e r n si n
t h ed i k eo u t c r o p ,
(2)
t h el a c ko ff e n i t i z e dh a l o e sa b o u tt h ed i k e s
(3)
t h e common o c c u r r e n c eo fr e p l a c e m e n t - t y p e
c a r b o n a t i t ed i k e s
(4)
t h el a c k
o f c a r b o n a t i t ed i k e si nt h es o u t h e r n
p o r t i o no ft h ea r e a .
.Page 115
is
O n l yo n eo t h e or c c u r r e n c eo cf a r b o n a t i t e s
from
New
1961).
M e x i c o l, o c a t e d
T h i sc a r b o n a t i t e
i n t h e M o n t eL a r g o
reported
area (Lambert,
i s a m a s s i v ed o l o m i t i c a r b o n a t i t e .
d i kw
e i t ah p a t i t em
, a g n e t i t ea, n m
d i c aO
. t h eor c c u r r e n c e s
co af r b o n a t i t ae frs oe u na ds s o c i a t ewdi t ha el k a l i c
1966).
c o m p l e x e s i n s o u t h e r nC o l o r a d o( H e i n r i c h ,
i s 520 m.y.
t h ce a r b o n a t i t eisC
n olorado
T h ea g eo f
et
(Olson,
al.,
1977).
are
Carbonatites
g e n e r a l al ys s o c i a t ewdi at hl k a l i c
1966).
i n t r u s(iH
v e si n r i c h ,
i n New Mexico. i n c l u d et h eP a j a r i t oM o u n t a i n
P r e c a m b r i a na g e
1 9 6 8 ) a n dt h eF l o r i d aM o u n t a i n
s y e n i t e( 1 1 7 0m . y .K
, elley,
s y e n i t e( 4 2 0
-
7 0 0m . y .B
, rookins,
Lemitar
1974).
T h i se v i d e n c e
a n a l k a l i icg n e o u ps r o v i n c o
eccurring
b se u g g e s t i v o
ef
C o l o r a da on d
A l ki an lt ir cu soi fv e s
New M e x i b
ce
ot w e e n
1100
a4
n2
d0
may
in
m.y.
The
M o u n t ac ianr b o n a t i tweosptubo
h
alerfidst
postulatedprovince.
C a r b o na n do x y g e ni s o t o p es t u d i e si nt h e
Wet
Mountain
c a r b o n a t i t ec o m p l e x C
, o l o r a d o c, l e a r l yi n d i c a t et h a tt h o s e
c a r b o n a t i t e sa r ef r o m
1979).
a d e e p - s e a t e ds o u r c e( A r m b r u s t m a c h e r ,
O t h ecr a r b o no, x y g e ns, u l f u ra, n d
strontium
isotope
s t u d i e sa l s oi n d i c a t e
a d e e p - s e a t e do ru p p e rm a n t l es o u r c e
1965;
f oc ra r b o n a t i t e( H
s ayatsu
e t, . a l . ,
1966;
Heinrich,
1966;
Taylor, et.al,
1967;
P o w e lel t, . a l . ,
Suwa,
et.al.,
Page 116
1975;
1975).
. M i t c h e lal n K
d rouse,
isotopevidence,
in
i t i s p r o b a b l et h a tt h ec a r b o n a t i t e s
a l s o a r ed e r i v e df r o m
t h eL e m i t a rM o u n t a i n s
It
um
p pasenortul re c e .
carbonatites
W i t thh ias b u n d a n c oe f
is
a d e e p - s e a t e do r
c o n c e i v tat hhbeal et
o f t h eL e m i t a rM o u n t a i n s
may b ed e r i v e df r o m
a
m a f isco u r cw
e h i c gh a vrei stetohm
e a f idc i k easn tdh e
d i o r i t e / g a b b r o ,a l t h o u g hp r e l i m i n a r yc h e m i c a ls t u d i e sa p p e a r
trends.
e xthnocaiohb
nteiytm i c a l
An
extensive
g e o c h e m i c a lni ds o t o p isct u dotyh
fLee m i t aMr o u n t a i n s
c a r b o n a t i t e sw o u l dh a v et ob ec o n d u c t e db e f o r ec o n s t r a i n t s
on t h e c o m p o s i t i o n o f t h e s o u r c e c o u l d b e a c h i e v e d .
E x p e r i m e n et avli d e nccoen f i r tmhmsaet w
l t ist h
a
in
v a r i e toycfo m p o s i t i o ncsapnr o d u ctehw
e i dvea r i a n c e
in
m i n e r a l o gayncdh e m i s t rsye e n
carbonatites
Lemitar
ti h
ne
t e m p e r a t u r e so f
from 1
-
1971).
Watk
aW
n
i ndy l l i e ,
s u g g e s t st h a tc a r b o n a t i t e s ,
Mountains,
450
-
Tehvei d e n c e
s i m i l a r i n c o m p o s i t i o nt ot h o s e
may
600
degrees
1000 b a r s( H e i n r i c h ,
to
1966;
t h ofsoeutL
in
hned m i tM
a ro u n t a i(nHs e i n r i c h ,
W y l l i e , 1.966;
similar
h abveeem
np l a c e d
C.
1966).
a n dp r e s s u r e sr a n g i n g
at
P a g e 117
STRUCTURE AND METAMORPHISM
INTRODUCTION
T h eL e m i t a M
r o u n t a i n sl i eo nt h ew e s t e r ne d g eo tf h e
R iG
o r a n dge r a b e nw, h e rne o r m afla u l ths a vue p l i f t e da'n d
Perxetpchoam
esmerTbto
dh
arcm
iekason.r p h o s e d
P r e c a m b r ri ao nc k s
are
s t r u c t u r a cl loym p l eFxo.l i a t i o n ,
of
f a u l st sh,e a r i nagbn,rde c c i a t i omn o, s t
which
are
L a r a m i d ea n dT e r t i a r ys t r u c t u r e sa, f f e c t e dt h eP r e c a m b r i a n
r o c kTd
sh.ief f i c ui lintntye r p r e t itn
Phg
ree c a m b r i a n
s t r u c t u r e i s i n d i f f e r e n t i a t i n gy o u n g e rc o m p l e xf a u l t i n ga n d
s h e a r i n gf r o mt h a to ft h eP r e c a m b r i a n .
T h eP r e c a m b r i a nr o c k sh a v eu n d e r g o n es u c c e s s i v ep e r i o d s
mineral
mo ef t a m o r p h i sm
ma, k itn
ihdgee n t i f i c a t ioofn
a s s o c i a t i o nd si f f i c u lTt .hr o
e c ka sar el sa of f e c t ebdy
as
r e t r o g r am
d e t a m o r p h i s smu,c h
b i o t i t ea n dt h es e r i c i t i z a t i o n
m e t a s o m a t i s ms, u c h
of
t hc eh l o r i t i z a t i o n
of f e l d s p a r s .T h ee f f e c t so f
as c a r b o n a t i z a t i o na n dh e m a t i z a t i o n ,a r e
s u p e r i m p o s eodv et rhm
e e t a m o r p h ifca b r iicn d i c a t i ntgh a t
m e t a m o r p h i s mo c c u r r e dp r i o tr oa l t e r a t i o n T
. h ec o m p l i c a t e d
s t r u c t u r at rl e n d s
in
the
Lemitar
Mountains
s e v e r a lp e r i o d so fb u r i a la n du p l i f td u r i n gt h eL a r a m i d e
T e r t i a r yo r o g e n i e s .C o n t a c tm e t a m o r p h i ce f f e c t sa r er a r e .
may
suggest
and
Page 118
METAMORPHISM
Generally, the mineral assemblages of
the
Precambrian
rocks in the Lemitar Mountains can be summarized as follows:
quartz-muscovite
quartz-muscovite-biotite-plagioclase-(garnet)
quartz-biotite-potassium feldsparplagioclase-(garnet)
blue-green hornblende-biotite-plagioclase-(garnet)
quartz-biotite-muscovite-potassium
feldspar-
plagioclase
These mineral assemblages represent the
the
greenschist
amphibolite
facies
(low
(medium
grade
grade
between
metamorphism)and
metamorphism,
the
Winkler,
Condie and Budding, 1979).
1976;
Regional
sediments.
metamorphism
The
are
consistent
amphibolite
of
facies
transition
crystals
completely
mineral assemblages and gneissic
with
facies
the
upper
greenschist
of metamorphism;
may
possibly
metamorphism.
recrystallized
The
be
presence
amphibolite
zone
facies.
foliation
and
lower
undulatory extinction
related
to
regional
of trace amounts of garnet in
some of the thin sections is suggestive of
the transitional
the.
between
the
Well-preserved
metamorphism
to
greenschist and lower
foliated
arkose
Page 119
i n c l u s i o n sa r ef o u n ds c a t t e r e dt h r o u g h o u tt h ed i o r i t e l g a b b r o
s u g g e s t i n gt h a t h i sp e r i o do fm e t a m o r p h i s mo c c u r r e dp r i o r
ttehom
e p l a c e m etoL
hnfet m i tdairo r i t e / g a b b rToh. e
f o l i a t i o nw i t h i nt h ea r k o s ei n c l u s i o n s
i s r a n d o m l yo r i e n t e d .
A t l e a s t o n eo t h e rp e r i o do fm e t a m o r p h i s mt h a ta f f e c t e d
Lemitar
t hCeo r k s c r e C
wa n y osne q u e n cael saof f e c t et dh e
d i o r i t e l g a b b r oa n dt h em a f i cd i k e s T
. h ep r e s e n c eo fg a r n e t
a n dt h et r a n s f o r m a t i o no fp y r o x e n e st oh o r n b l e n d e ,f o u n d
in
t h e Lemitar d i o r i t e l g a b b r o ,a r ei n d i c a t i v eo ft h et r a n s i t i o n
b e t gwtreheeenn s caah
mni pd
sh
t i b ogl ri atoedf e s
metamorphio
sm
c c, u r r i n g
after
et h
mep l a c e m
t hoeefn t
dioritelgabbro.
I t i s d i f f i c u l tt od e t e r m i n ew h e t h e r
t h e g r a n i t i cr o c k s
h a v eu n d e r g o n em e t a m o r p h i s mF. o l i a t i o nw i t h i nt h eg r a n i t i c
rocks
is
r a n d o molryi e n taelnd
odc a l i zaendd
may
be
p a r t i a l rl ey l a t tet h
eodm
e p l a c e m etonh
gfter a n i t e s .
M o r t atre x t u r eas r oe f t e pn r e s e n tb, utth e s teo o
may
be
r e l a t e tdtoheem p l a c e m e not fhge r a n i t e sC. r o s s c u t t i n g
m a f idci k ehsa vbee em
n etamorphosed,
as
i n d i c a t eb
d tyh e
transform
p yao
rt h
ofi oo
x nrteo
nn be lse cn ldeea,r l y
indicating
t h alto w
gradm
e etamorphism
occurred
e m p l a c e m e n to ft h em a f i cd i k e sa n dt h eg r a n i t e s .
after
the
P a g e1 2 0
T chaer b o n a t i tperso b a bhl aybv e ue n a f f e c t be y
d
m e t a m o r p h i sdm
ue
ttohlea c k
of
a
m e t a m o r p hfiacb r i c .
M o r ttaerx t u r ae n
u
sd
n d u l a t o er y
x t i n c t i ofo
nefsl d s p a r
c r y s t a al sr p
e ,r o b a b lr ye l a t et dohi en t r u s i o n
of t h e
c a r b o n a t i t ed i k e .
FOLIATION
Foliation
i n C o rt hk C
es casre
ned
ywiom
nents
a p p r o x i m a t e lp
y a r a l l e lrse l i cbt e d d i n gR. e l i cbt e d d i n g
d i s t i n g u i s fhrfeoodm
liation
by
is
c otalenoxdrt u r a l
c o n t r a s t sT. hter e nodffo l i a t i oanl o nC
gorkscrew
Canyon
40
N40W t o N 4 0 E , w i t he a s t e r l yd i p os f
r a n g efsr o m
-
70
d e g r e e sR. e l i cct r o s s b e d d i n ag n gd r a d e bd e d d i n ign d i c a t e s
t h a tt h es e q u e n c e
i s p r e s e n t l yu p r i g h t ,y o u n g i n gt o w a r d st h e
east.
are
V efreo
yw
utcrops
exposed
in
foun
bd
etwee
th
snee d i m e n t s
C o r k s c r e wC a n y o na n dt h ea r k o s ef r o mt h el o w e s t
e x p o s e du n i it nt h es o u t h e r np o r t i o no ft h e
1).
map
area
(Map
If
the
T hfeo l i a t i oont fhaer k o spea r a l l e ltsheea s t - w e s t
t r efon
ofd
l i a t tigihonene i s sgirca n i t e .
sediments
are
s t i l l i n a n u p r i g h tp o s i t i o ni nt h es o u t h e r n
p o r t i o n o f t h es t u d ya r e a t, h e nt h ea r k o s e
sedimen
x tp o s eTda
hr.g
iesel a t i o n s h i p
is
is
t h eo l d e s t
uncertain,
P a g e1 2 1
well
b e c a u spe r i m a r tye x t u r easrne o t
may
a r k o s ae n d
faulting
may
this
from t h e
o f f s e t t h ae r k o s e
i n C o r k s c r e wC a n y o n .T h ef o l i a t i o no ft h e
s e d i m e n t se x p o s e d
arkose
have
in
preserved
also
be
due
to
the
intrusion
o tf h e
gneissic
granite.
A Tertiaryfaultcutsthegneissicgranitesouthofthe
i n t r u s i v ce o n t a cw
t ith
t h ae r k o s e
f a u l t , f o l i a t i o nt r e n d s
North of t h i s
(Map 1).
to
east-west a n dd i p s
t h ne o r t h .
i s s t i l l i an n
Souto
h tfh i fs a u l tf, o l i a t i o n
east-west
directionb
, ud
t i p st ot h es o u t h w
, h i l ef u r t h e rs o u t ht h e
t o t h en o r t h T
. h i sf o l i a t i o n
d i pd i r e c t i o nc h a n g e s
may b e
of t h e g r a n i t e .
p a r t i a l l yi n h e r i t e df r o mt h ee m p l a c e m e n t
F o l i a t i o n i s a b s e n tt op o o r l yd e v e l o p e di nt h en o r t h e r n
g r a n i t i rc o c k st,h L
e e m i t a dr i o r i t e . j g a b b r oa, n d
thm
e afic
dikes.
Some f o l i a t i o n , p a r a l l e l t ot h ee d g e so ft h ed i k e s ,
i s p r o b a b l yr e l a t e dt o
o c c u r si nt h ec a r b o n a t i t ed i k e sa n d
t heem p l a c e m e notth
fdei k e sF.o l i a t i oinnt h,Lee m i t a r
diorite/gabbro
is
restricted
to
s h e a zr o n e as n d
n e a trh e
westernandnortherncontactswiththealteredfaciesofthe
P o l v a d e r aG r a n i t eF. o l i a t i o ni nt h eb i o t i t ea n dP o l v a d e r a
G r a n i t e i s p o o r ld
ye v e l o p e d
to
a b s e n ta, n d
is
r e l amt eiogd m i t i z a t i o n
may
represent
prim
sf ltao
rruw
yc t uwrfh
eositllh
,ieaeitni o n
m u s c o v i t e - b i o tgi tr ea n i t e
o c c u r r i nagl o n g
the
i n t r u s i vceo n t a cwt i tt hh e
Lemitar
Page 1 2 2
diorite/gabbro.
FAULTS
F a u l t i nhgaosc c u r r e d
determination
on
a
l a r gsec a lme a k i ntgh e
o f t h i c k n e s sa n do r i e n t a t i o n
d i f f i c u l tt od e t e r m i n eT. h e
of t h es e d i m e n t s
L a r a m i d e o r o g e n ay n T
d ertiary
B a s i n - a n d - R a n g e - t yf pa eu l t i( nr igf t i no gv )e r p r i n t eh de
P r e c a m b r i af na b r i rc e, i n f o r c i nt g
hneo r t h e r lsyt r u c t u r a l
trends
of
tPh ree c a m b r itaenr r a iLna. r a m isdter u c t u r e s
c o n s i s t of b r o a d f o l d s a n d r e v e r s e f a u l t s
woodw ward,^ 1 9 7 3 )
~
a n dr o t a t i o n a le f f e c t sd u r i n gt h eL a r a m i d ea r em i n o r( a b o u t
1 5 d e g r e ews e s t ,
Woodward,
19731,
w h i lT
e e r t i a r fya u l t s ,
r e l a t e dt or i f t i n g ,t i l t e dt h eP r e c a m b r i a nr o c k se v e nm o r e
( a p p r o x i m a t e l y 4 0 d e g r e e sw e s t ,
Woodward,
1973).
N o r t h - t r e n d i n gf a u l t sw i t hs i l i c i f i e dc a r b o n a t e dg o u g e
z o n e sc u tt h er o c k sa l o n gC o r k s c r e wC a n y o na n da l s oc u tt h e
P o l v a d e r aG r a n i t ea l o n gt h e
Not
m a i n a r r o y oi ns e c .
a l l o f t h e s ef a u l t sc a nb e
mapped.
Widths
b r e c c i az o n e sr a n g ei nt h i c k n e s sf r o m
o f t h ef a u l t
a few cm.
f a u l at sl scout htPeo l v a d e rGa r a n i t e
d i o ; i t e / g a bT
b er or Pt.airanerdcya m bfraiaaurnlet s
t o a meter.
of C o r k s c r e w
S e v e r a le a s t - w e s tf a u l t sc u tt h es e q u e n c es o u t h
C a n y o n f, o r m i n ga r r o y o ss u c h
3 1 (Map 1).
a s C o r k s c r e wC a n y o n .
and
East-west
t hLee m i t a r
P a g e1 2 3
t o d i s t i n g u i s ho u t s i d eo fC o r k s c r e wC a n y o nd u et o
difficult
o f g o o edx p o s u r e s .
t h el a c k
A few
s h e a zr o n e w
s ithin
the
s e d i m e n t sa n da l t e r e df a c i e so ft h eP o l v a d e r aG r a n i t e
for
i n d i c a t i vopefr e - L a r a m i dfea u l t s ,
affect
may b e
t h e szeo n eosn l y
t hPer e c a m b r i ar no c k F
s .ot hrpeu r p o s e s
report,
breccia
of t h i s
as nh d
ze o
an
rh eabsvedeeens c r i b e d
separately.
A n o r t h w e s t - t r e n d i n gT e r t i a r yf a u l (t C h a m b e r l i n 1
, 9.78)
6 a n d 7 (Map 1).
c u t st h eP r e c a m b r i a nr o c k si ns e c .
b r e c c i a t i o na l o n gt h en o r t h e r np a r t
7 o c c u r as n d
t h ef a u l at n dt h e
central part
mafic d i k e s i n i n t h e
d i s c o n t i n u i t yo fs e v e r a l
o sf e c .
of
is s u g g e s t i v o
ef
Local
a f a u l tG
. enerally,
a r e t o o poor t o
t heex p o s u r eitsnhPe r e c a m b r i arno c k s
e x t e n dL a r a m i d ea n dT e r t i a r yf a u l t st h a tc u t h ea d j a c e n t
P h a n e r o z o i cr o c k s .
SHEAR
ZONES
A n o r t h e a s t - t r e n d i n gs h e a rz o n ec u t sa c r o s st h ew e s t e r n
quarter
of t h es e c t i o na l o n gC o r k s c r e wC a n y o n B
. e d d i n gh a s
b e e no b l i t e r a t e da n d
u n d u l a t o reyx t i n c t i o n
i n t h i ns e c t i o n ,c a t a c l a s t i ct e x t u r e s ,
of
t hger a i n as n
,s du t u r egdr a i n
b o u n d a r i e s a r e p r e s e n tB. o u d i n a gset r u c t u r e(ss e v e r a l
across)
subparallel
t ht re e n d
of
the
original
cm.
bedding
P a g e1 2 4
B o u d i n a g ei n d i c a t e st h es t r e t c h i n ga n ds h e a r i n go fl a y e r e d
i s formb
ed
y
competen
an
ti d
ncompeten
r ot c k Fs .o l i a t i o n
s m a l l - s c a l e( w a v e l e n g t h
of s e v e r a l cm.) h i g h l yf o l d e dq u a r t z
a n df e l d s p a rb a n d sa n db yt i g h t p
, t y g m a t i cf o l d sw h i c ha r e
i n p l a c e( s ef ei g .
o f t es n
heared
Woodward,
s e e sn o u t h
1973).
T h e1 2 0
-
18-A
and
B,
150 m e t e rw i d es h e a rz o n e
of Corkscrew
C a n y oannedn d s
at
54,
p.
i s not
t h ei n t r u s i v e
c o n t a c tw i t ht h em u s c o v i t e - b i o t i t eg r a n i t e .
T h i s s h e a rz o n e
i s P r e c a m b r i a ni na g ea n dp r o b a b l yo c c u r r e db e f o r eo rd u r i n g
t h ei n t r u s i o n
o f t h em u s c o v i t e - b i o t i t eg r a n i t e ,
zone a f f e c t so n l yt h es e d i m e n t s .
as t h e s h e a r
I t may e v e nb er e l a t e dt o
t h ei n t r u s i o no ft h em u s c o v i t e - b i o t i t eg r a n i t e .
S h e a r i n gh a sa l s oa f f e c t e dt h ea l t e r e df a c i e s
of
P o l v a d eGr raa n w
i th
e ezroen e s
of
f o l i a t qe u
dartz
the
and
f e l d s p a lr a y e r o
s c c u ri, n d i c a t i v eo if n t e n s es h e a r i n gT
. he
t r e n do ft h i sf o l i a t i o n
i s n o r t h e a s tw i t h
a b o u6dt2e g r e e T
s .h si sh e a r i n g
may
P r e c a m b r i a nf a u l t i n g ,b e c a u s ef a u l t i n g
a western d i p of
a l s boree l a t e tdo
a n d s h e a r i n gd o e sn o t
a p p e a rt oh a v ea f f e c t e dt h eP a l e o z o i cs e d i m e n t s .
S h e a r i n go c c u r sw i t h i nt h eL e m i t a rd i o r i t e j g a b b r on e a r
t h ec o n t a c tw i t ht h eP o l v a d e r aG r a n i t e .T h i ss h e a r i n gc o u l d
bdeu e
t o a P e n n s y l v a n i a nr e v e r s ef a u l (t C h a m b e r l i n ,
1978)
ottrohi en t r u s i ootnfhPeo l v a d e rgar a n i t eF.o l i a t e d
c h l o r i t e -a n db i o t i t e - r i c hz o n e s ,s e v e r a l
meters a c r o s s , a r e
Page 1 2 5
I
l o c a l l yp r e s e n ta l o n gt h ei n t r u s i v ec o n t a c t T
. h ef o l i a t i o n
i s a b s e n tw i t h i nt h e
s u b p a r a l l e l st h ei n t r u s i v ec o n t a c ta n d
a
P o l v a dG
e r a n si tueg, g e s t i n g
r e l a t i o n st ht oie p
e m p l a c e m e n to ft h eP o l v a d e r aG r a n i t e .
BRECCIATION
S e v e r a l s m a l l ( s e v e r a lm e t e r sa c r o s s )h e t e r o l i t h o l o g i c
within
b r e c c i za o n eos c c u r
g e n e r aclel m
y ented
by
t h se e d i m e n t s
w hc iatreb o n aAt ne g
. ur loacrk
f r a g m e n t sa r ec o m p o s e do fP r e c a m b r i a ng n e i s s i c
and granitic
w i t h a l i g h t - c o l o r e dr e a c . t i o n
r o c k sa n da r eo f t e ns u r r o u n d e d
rim.
(Map 1) a n a
dr e
as
B r e c c i a to
hi o
ca cd
n u rar fm
etde rt a m o r p h i s m
i n d i c a t e d by t h e r a n d o m l y o r i e n t e d f o l i a t e d r o c k f r a g m e n t s .
I nc o n t r a s t ,s e v e r a lm o n o l i t h o l o g i cb r e c c i az o n e so c c u r
w i t h i nt h em u s c o v i t e - b i o t i t eg r a n i t e
(Map 1) w h e r et h er o c k
f r a g m e n ct so n s i es nt t i r e o
lmyfu s c o v i t e - b i o t i gt er a n i t e .
The
matrix
is
i s b l a c ka n dv e r yf i n e - g r a i n e da n dc a r b o n a t e
a b s e n ft r o mt h em a t r i x T
. h er o c kf r a g m e n t sa r ea n g u l a ra n d
u n s u p p o r t e(ds u r r o u n d e d
by
m a t r i x ) a n d r a n d o m layr r a n g e d ,
s i m i l a r t or o c kf r a g m e n t sf o u n di nt h eb r e c c i a t e ds e d i m e n t s .
T h i bs r e c c i za o n ree p r e s e n t ps a rottfh leo w
angle f a u l t
f o r m i nt gheea s t e rcno n t a cb te t w e et nhPer e c a m b r i aann d
P h a n e r o z o i cs e d i m e n t sa n dv o l c a n i c s( C h a m b e r l i n ,
1978).
P a g e1 2 6
in
A b r e c c i a t e d a n d s h e a r e zdo noe c c u r s
portion
of
t hL
e e m i t adr i o r i t e / g a b b r o
t h ec e n t r a l
(Map 1, s e c .
6 and
71, w h e r ef r a g m e n t so fd i o r i t e / g a b b r oh a v eb e e nc e m e n t e da n d
forms
an
a n g u lbarre c c iTadh. ieo r i t e / g a b bhrbaoes e n
a
s l i g hftol lyi a at enl tde tr oe d
c h l o r ai tned-
biotite-ricg
h o u g eF. o l i a t i o w
n i t h i tnh i ss h e azr o n de i p s
t totohne o r t h w e satb o u t
44
h a v eb e e no b l i t e r a t e da n ds h e a r e d .
d e g r e e sO. r i g i n at el x t u r e s
Some o ft h e s ez o n e s
may
r e p r e s e nl et n s eossfe d i m e n t a ri yn c l u s i o n T
s .h si sh e a r e d
b r e c c izao n e
(1978
may
h a vree s u l t efdr o m
f a u l t i n gC; h a m b e r l i n
s h o w st h ea r e at ob et r a n s e c t e db yt w of a u l t s
e a r l y O l i g o c e n et r a n s v e r s ef a u l t
fault
-
an
a n d a P e n n s y l v a n i a nr e v e r s e
Page 127
MINERALIZATION
Five periods ofmineralization affected the Precambrian
rocks in the Lemitar Mountains (in order of decreasing age):
(1) Precambrian pegmatite and quartz veins
(2) Carbonatite dikes (iate Precambrian)
(3)
Phanerozoic barite-galena-copper veins
(4) Phanerozoic barite-galena-sphalerite veins
(5)
Barite veins
Mining claims cover much of the eastern portions of the
area ( sec.
map
5, 6, and ~ 7 , Socurro -County-eourthouse "Records
Precambrian
pegmatites
are
of
the
simple
type,
consisting
of
unzoned
feldspar,
quartz,
and
mica
as
previouslydiscussed(seeGranitic
appear
to be
Rocks).
Quartzveins
barren of any other mineralization.
Both are
discontinuous, forming poorly exposed outcrops.
The
carbonatite
dikes
are
composed
bearing minerals, radioactive minerals,
of
rare-e?rth
and fluorite.
High
areas of radioactivity (100 times background) occur in
sec.
6 and
7.
Two samples of high radioactivity were analyzed
and found to contain 0.08
(190 ppm U ) and 0.06%
U308(ChristopherRautman,personal
communication).
eight-samples analyzed by the author ranged from
0.0045%
U308
(Appendix
B).
(143 ppm
0.0011
Megascopic fluorite
U)
The
to
is found
P a g e1 2 8
walls of s e v e r a l p r o s p e cpt i t isn
a l o n tgh e
concentration
7.
sec.
The
o f r a r e - e a r t h e l e m e n t s may b er e l a t i v e l yh i g h
b e c a u s eb a s t n a e s i t e
i s present.
P h a n e r o z o i cb a r i t e - g a l e n a - c o p p e rv e i n so c c u ra l o n g
the
w e s t e rcno n t a cwt i tthhPeh a n e r o z o isce d i m e n t P
s .r o s p e c t
a shaft
p i tasn d
18)
(sec.
e x p o st h
em
i si n e r a l i z a t i o n .
C o p p e rm i n e r a l sc o a tt h ef r a c t u r ea n dj o i n ts u r f a c e s
of t h e
P r e c a m b r i a nr o c k si nt h ev i c i n i t yo ft h em i n e r a l i z a t i o n .
At
o f t hPe o l v a d e r a
o n leo c a l i t w
y i t h i tnh ae l t e r e fda c i e s
G r a n i t e , a v e i n o f g a l e n a s, p h a l e r i t e c, h a c o l c i t e q, u a r t z ,
minerals crosscuts a
f l u o r i t e ,b a r i t e ,a n ds e c o n d a r yc o p p e r
Some s i l v e r a nzdi nhca vbee erne p o r t e d
p e g m a t i tdei k e .
f r o mt h e s ev e i n s( L a s k y , 1 9 3 2 ) .
P h a n e r o z o i cb a r i t e - g a l e n a - s p h a l e r i t ev e i n so c c u rw i t h i n
P h a n e r o z o ilci m e s t o nael o n tgh e
T h ims i n e r a l i z a t i o n
small
is
l o c a l i z eadnrde s t r i c t etdo
of
vwe tii h
tnhesi n
some
of
o u t c r olopi fm
s e s t o nTesh.teu d y
sections
three thin
limestone
c o a r s e - g r a i n e dl i m e s t o n ec r o s s c u tb yt h i n
reveals
v e i n l e t s o fb a r i t e
and c a l c i t e c o n t a i n i n g a l e n a n d
s p h a l e r i t eT. h e
lack
a p a t i t e ,m a g n e t i t e ,a n db i o t i t ec l e a r l yd i s t i n g u i s h e s
v e i nfsr o m
c a r b o n a t i tdei k e sS. m a lqlu a n t i t i e s
were
s h i p p ef rdoomntohlefae r g ze or n w
e si t h ti hn e
l i m e s t o n e( s e c .
5).
eastern c o n t a c t (sec.
5 , Map 1).
of
these
of
barite
Page 129
B a r i t e v e i n s , a l s o P h a n e r o z o i c ,o c c u ra l o n gt h ee a s t e r n
east-west.
B a r i t ve e i nos f t e n
i n t r u d teh ce a r b o n a t i t d
e i k e sT. h i m
s ineralization
may
c o n t a c tg, e n e r a l l sy t r i k i n g
related t o otherbaritemineralization
T h eP h a n e r o z o i cm i n e r a l i z a t i o n
be
i n thearea.
i s n o at s s o c i a t e dw i t h
tcha er b o n a tdi ti ek T
emsh.ien e r a l o g aitenesd
xtures
or
d i f f e rT
. h ec a r b o n a t i t ed i k e sd on o ct o n t a i ns p h a l e r i t e
g a l e n a a, n db a r i t e
i s r a r e i n t h ec a r b o n a t i t e s T
. h eb a r i t e
mineralizatid
oo
nneiosntc l u ad pe a t i tme a, g n e t i toer,
b i o t i t eF
. i e l dr e l a t i o n s h i p s u g g e s t h a t
are
o l d et rh.talhniem e s t o tnhehaot st tb
hsae r i t e
mineralization.
the carbonatites
P a g e1 3 0
G E O L O G I C HISTORY, TECTONIC SETTING, AND CONCLUSIONS
A summary
of
t h eP r e c a m b r i a ng e o l o g i ch i s t o r yo ft h e
L e m i t a r M o u n t a i n s i s p r e s e n t e d i n t a b l e 19.
r e c o r d e di nt h e
The f i r s t e v e n t
L e m i t a r M o u n t a i n s i s t h ed e p o s i t i o no ft h e
o f t w ou n i t s
C o r k s c r e wC a n y o ns e q u e n c ec o n s i s t i n g
c h a r a c t e r i z e db ym a s s i v ea r k o s ea n dU n i t
-
Un'it I
I1 c h a r a c t e r i z e d b y
i n t e r b e d d e df, o l i a t e d
a r k o s e ss, u b a r k o s e sa, n d
quartzites.
is
T h isse q u e n coesfe d i m e n t s
similar
t ot h ef e l d s p a t h i c
New
q u a r t z i t e - a r k o s ea s s o c i a t i o ne x p o s e dt h r o u g h o u tc e n t r a l
. .
19791, a l t h o u g hc o r r e l a t i o nt o
M e x i c o( C o n d i ea n dB u d d i n g ,
p a r t i c u l abr a s i n
is
h a v be e e en m p l a c e d
a f t e r t h ed e p o s i t i o n
although
I m a f i c d i k ef so l l o w e dM. e t a m o r p h i s m ,
of t h es e d i m e n t so c c u r r e db e f o r e
faultinga
, n ds h e a r i n go f
..
I m a f di ci k eTs .h e .
d
ou
r r i ne gm p l a c e m e tonhSft et a g e
e m p l a c e m e not tfh e
of
may h a v e
a t t h e same t i m e a s t h ey o u n g e rg r a n i t e s .T h e
i n t r u s i oonSf t a g e
intrusion
t h es e d i m e n t s ,
it i s p o s s i b l e t h a t t h i s f o l i a t e d , g r a n i t e
b e e ne m p l a c e d
may
u n c e r t a i nT.hgen e i s s Tgcr a n i t e
of
a
L e m i t a r d i o r i t e l g a b b r o f. o l l o w e db y
Stage
I1
mafic
the
d t koecsc u r rne edxTth. e
similarity im
n i n e r a l o g ay n tde x t u r be e t w e e tnh L
e emitar
d i o r i t e / g a b b r oa n dt h e' g a b b r oo f
Garcia C a n y o(nM a g d a l e n a
g a b b r o ) s u g g e s t s t h a t t h e t w o mafic u n i t s may b e r e l a t e d t o
a s i m i l a r s o u r c et h a tc r y s t a l l i z e da b o u t
1.5 b.y.
according
TABLE 19
SUMMARY OF THE G E O L O G I C HISTORY OF THE PRECAMBRIAN
ROCKS
(1) D e p o s i t i oon
t fhCe o r k s c r e w
C a n y osne d i m e n tdse r i v e d
f r o m a g r a n i t i c or g n e i s s i c s o u r c e .
( 2 ) P o s s i b l ee m p l a c e m e n o
t tf h eg n e i s s i cg r a n i t e a, l t h o u g h
thisfoliatedgranite
may h a v eb e e ne m p l a c e da l o n gw i t h
t h eo t h e rg r a n i t i cr o c k sl a t e r
on.
( 3 ) I n t r u s i ooSnft a g e
I m a fdi ci k ae n
smde t a m o r p h i s m ,
f o l d i n g ,f a u l t i n g ,a n ds h e a r i n g
o f t h es e d i m e n t s .
( 4 ) E m p l a c e m e n to ft h e
Lemitar d i o r i t e l g a b b r o .
( 5 ) I n t r u s i o n of S t a g e I1 m a f i cd i k e s .
( 6 ) E m p l a c e m e n to ft h eg r a n i t i cr o c k s ,o f t e na s s o c i a t e dw i t h
m i g m i t i z aatL
nisd
eoh
tm
h
/neoeaiortrfai n
rg
diorite/gabbro.
( 7 ) I n t r u s i o no fp e g m a t i t e sa n dq u a r t zv e i n sa n dd i k e sa n d
i n t r u s i o no fS t a g e
111 m a f i cd i k e s ,f o l l o w e d
p e r i o do fm e t a m o r p h i s m .
by a f i n a l
( 8 ) I n t r u s i o no fc a r b o n a t i t e sa n da s s o c i a t e df e n i t i z a t i o n
t hLee m i t d
a ri o r i t e j g a b b ra ongdr a n i t ri o
ccks.
i n c l u d eb r e c c i a t i o n c, a r b o n a t i z a t i o n a, n dh e m a t i z a t i o n
o ft h ec o u n t r yr o c k s .
of
May
P a g e 132.
t o R b / Si rs o c h r odna t i nogt fhgea b b rooGf a r c iCa a n y o n
the Lemitar
( W h i t1e9, 7 8T)gh. rea n i triocciknst r u d e
d i o r i t e / g a b b r oa n do f t e na r ea s s o c i a t e dw i t hm i g m i t i z a t i o n
a n ds h e a r i n go ft h ed i o r i t e / g a b b r o .M o s tg r a n i t i cp l u t o n i s m
i n c e n t r a l New
-
M e x i cooc c u r r ebde t w e e1n. 2
1.4
bay.
1 9 7 9 ) a n dp e r h a p st h eL e m i t a rg r a n i t e s
( C o n d i ea n dB u d d i n g ,
w e r ee m p l a c e dd u r i n gt h i sp e r i o dd u et ot h es i m i l a r i t y
in
m i n e r a l o g yt,e x t u r ea, n d
chemistry
between
these
granites.
a
Simplu
e ,n z o n epde g m a t i t ea snqdu a r tvze i nr se p r e s e n t
f i n a ls t a g eo fg r a n i t i cm a g m a t i s m
i n t h eL e m i t a rM o u n t a i n s .
S t a g e I11 m a f i cd i k e si n t r u d e dt h eg r a n i t i cr o c k s ,f o l l o w e d
by
a
perioo
dm
f e t a m o r p h i s mT. h ien t r u s i o o
ncf a r b o n a t i t e
d i k easnvde i nasl o npgr e - e x i s t i nfga u l tasnfdr a c t u r e s
was
f o l l o waendd
o f taesns o c i a tw
ed
ith
normal
sodic
L e m i t a r d i o r i t e / g a b b r oa n dt h eg r a n i t i c
f e n i t i z a t i o no ft h e
r o c kB
s .r e c c i a t i o cna, r b o n a t i z a t i o ann,hde m a t i z a t i oonf
t h ec o u n t r yr o c k s
may a l s ob ea s s o c i a t e dw i t ht h ei n t r u s i o n
otfh ce a r b o n a t i t e sL. a r a m i d e
a n d T e r t i a r ys t r u c t u r e s
are
s u p e r i m p o s e do v e rt h eP r e c a m b r i a nf a b r i c .
T hme a f ir co c kasrper o b a b lmy a n t l e - d e r i v efdr o m
similar
s o u r cT
e .hl iet h o l o g i c a l hl ye t e r o g e n e o u
Lse m i t a r
diorite/gabbro
may
d i f f e r e n t i a t i o no f
hav
bee
dn
erive
f rdoem
i t hleart e
a g a b b r o i c magma o ri n j e c t i o na n dm i x i n g
of g r a n i t i c magmas w i t h a g a b b r o i bc o d yT. h m
e a f i dc i k e s ,
a
P a g e 133
may r e p r e s e n t a f r a c t i o n
s o m eo fw h i c hi n t r u d et h eg r a n i t e ,
of t h e s a m eg a b b r o i cs o u r c e .
T h eg r a n i t e cs a nb ed i v i d e di n t ot w og r o u p b
s a s e do n
similar
-
compositions
G r o u p I ( g n e i s s i cg r a n i t e b, i o t i t e
I1 g r a n i t e s( m u s c o v i t e - b i o t i t eg r a n i t e ,
g r a n i t e a) n d
Group
in
K20 a nhdi g h e r
CaO
i n S i 0 2a n d
I g r a n i t e sa r el o w e r
P o l v a d e r ag r a n i t e ) G
. roup
and
MgO
granites.
similar i n c o m p o s i t i o n
G e o c h e m i c a lm o d e ls t u d i e so ng r a n i t e s
1978)
t o G r o u p I g r a n i t e( sC o n d i e ,
I1
t h aGnr o u p
s u g g e st th apta r t i a l
meltino
gsf i l i c e o u gs r a n u l i t e istnh leo w ecr r u sct o u l d
Group
I1
I
similar i nc o m p o s i t i o nt oG r o u p
producm
e elts
granites
a rsei m i l a r
in
c o m p o s i t i om
t one l t s
p r o d u cfberyd
a c t i o ncar ly s t a l l i z a t i o n
1978).
magmas ( C o n d i e ,
e m p l a c e d a t d e p t h s of 2
granites.
of
granodiorite
T h eg r a n i t i cr o c k sa r et h o u g h tt ob e
-
1 3 km.
a s e v i d e n c e db yf i e l da n d
e x p e r i m e n t a ls t u d i e s .
A carbonatite
rocks
as
d i k e sa n d
u p p em
r antle
carbonatites
magma
i n t r u d et d
hoel d eP rr e c a m b r i a n
v e i n s a n d was p r o b a b l yd e r i v e df r o mt h e
a s e v i d e n c e d by e x p e r i m e n t adl a t af r o mo t h e r
similar
in
c o m p o sLti hettiem
oo int a r
c a r b o n a t i t eTs .hr ae n d oomr i e n t a t i o n
d i k e ss u g g e s tt h a t
of
t hcea r b o n a t i t e
a c a r b o n a t i t e magma p e n e t r a t e dt h ec r u s t
b e n e a tt hhper e s e ne tr o s i osnu r f a caent dhcea r b o n a t i t e
magma
f o l l o w e dp r e - e x i s t i n gf r a c t u r e sa n dz o n e so fw e a k n e s s
P a g e 134
i tnhPe r e c a m b r i a rno c k sP. r e l i m i n a r gy e o c h e m i c aslt u d i e s
do
n o te x h i b i ta n yc h e m i c a lt r e n d sb e t w e e nt h ec a r b o n a t i t e s
a n d t h e mafic d i k e s( f i g .
11).
of
T theex t u r ems ,i n e r a l o gayg
n, e
do c h e m i s t r y
the
in
C o r k s c r e wC a n y o ns e d i m e n t sa r ec o n s i s t e n tw i t hd e p o s i t i o n
a
fluvial
continental-rift
or
a
r a p i d rl iys i nc g
ontinental-margin
9) and
settinB
g .i m o d (afl i g .
thd
eeposition
a
d eel nt aviicre oi tnhim
n
e er n t
or
of
m a g m a t i sf m
ollowed
alkali
a
i s c o n s i s t e nw
t ith
t h see d i m e n tas n d
c o n t i n e n t a l - r isf et t t i n T
g .h e sc eo n c l u s i o ns u
s g g e tsht a t
Lemitar Mountains i s
t h teh P
e r o t e r o z o i .ct e r r a i n
o tfh e
a
consisten
wti t h
as
c o n t i n e n t a l - r i sf et t t i nsgu c h
(1979).
m u l t i p l e - r i f ts y s t e mp r o p o s e db yC o n d i ea n dB u d d i n g
T h ec a r b o n a t i t e s
i n t h eL e m i t a rM o u n t a i n s
M o u n t a i n s a) n d
may b eo f
i n C o l o r a d(oW eM
t o u n t a i n sI ,r o n
New M e x i c o
(MontL
e a r g oF, l o r i d M
a ountains,
P a j a r i tM
o o u n t a i nT
) .h e
Wet
M o u n t a i na snI d
r oM
nountain
com
C po llieoncxroa
e nd
s soi s t
of
syenm
i t ea sf i, c
of
n e p h e l i n e - b e a r i nr g
o c k as n,cda r b o n a t i t ea snadr e
similar
age
-
a b o u t 520 m.y.
M o n t eL a r g oc a r b o n a t i t e
thebasis
( O l s o ne,t
al.,
1977).
a
The
(New M e x i c o )h a sb e e ni d e n t i f i e do n
of c a r b o n a t i t e f l o a t i n
L a r g oa r e aa n d
a
i f s o may b er e l a t e dt o
l a t eP r o t e r o z o i c - C a m b r i a na g ea n d
o t h e ar l k a l ri o c k fs o u n d
the
a n a r r o wz o n ei nt h eM o n t e
i s t h o u g h t ob eP r e c a m b r i a ni na g e
on
the
P a g e 135
basis of f i e l dr e l a t i o n s h i p s( L a m b e r t ,
1961).
I t i s similar
i anp p e a r a n caen m
d i n e r a l o g tytohcea r b o n a t i t eostfh e
Lemitar
MountaR
i nasd. i o m e dt reitce r m i n atthioe
ofn s
s y e n i t e s of F l o r i d M
a o u n t a i n rs a n g fe r o m
420
to
a n da r e
m.y.
a t h e r m a l (magmatic o r
v e r y u n c e r t a i nd u et oe i t h e r
m e t a s o m a t i c e) v e n t
700
or mixino
gyf o u n g esr y e n i t i c
material
w i tohl d egrr a n i t irco c k(sB r o o k i n s1,9 7 4 )T. hael k a l i n e
r o c k s a t P a j a r i t oM o u n t a i n ,
New M e x i c o ,c o n s i s t
of
t o be n e a r
a n dg n e i s s e s ;r a d i o m e t r i cd a t i n gs h o w st h er o c k s
1 . 1 7 , b . y( .K e l l e y ,
1968).
syenites
T h oe c c u r r e n c oetfh e s ae l k a l i c
r o c k sa n dt h ec a r b o n a t i t e si nt h eL e m i t a rM o u n t a i n s
may b e
s u g g e s t i v e .of.a n a l k a l i . p r o v . i n c e . i n C o l o r a d o a n d
0.4
r a n g i n igan g fer o m
1 . a2 n d
bey.
N.ew
Mexico
An a l k a l pi r o v i n c e
a c o n t i n e n t a l - r i f ts e t t i n gi nt h e
w o u l db ec o n s i s t e n tw i t h
Lemitar Mountainsand.amultiple-riftsettingthroughoutthe
s o u t h w e s t e r n U.S.
a s p r o p o s e db yC o n d i ea n dB u d d i n g( 1 9 7 9 1 ,
b e c a u s ec a r b o n a t i t e sa r e
of
crustal
w e a k n essus c h
( B a i l e y , 1961).
known t ob ea s s o c i a t e dw i t ha r e a s
as
a
c o n t i n e n t a l - r i sf te t t i n g
REFERENCES C I T E D
1954,
Anderson, E.C.,
Mexico:
New
O c c u r r e n cU
oe fsr a n i uO
mriens
New
Cir.
M e x i cBou r e aMu i n M
e s i n e rR
a le s o u r c e s ,
2 9 , 27 p.
Anderson, E.C.,
their
1 9 5 7 , T h eM e t aR
l esourceo
sf
1954:
E c o n o mF
i ce a t u r eTsh r o u g h
N e w M e x i cBou r e a u
1 9 7 9 , R e p l a c e m e natn pd r i m a r m
y agmatic
Armbrustmacher, T . J . ,
c a r b o n a t i t e sf r o mt h e
Wet M o u n t a i n sa r e a ,F r e m o n ta n dC u s t e r
C o u n t i e sC, o l o r a d oE: c o n. G
. eol.,
V.
7 4 , 888
1 9 6 1 , The
mid-Zambezi-Luangwa
rift
v.
9 8 , p.
c a r b o n a t i t ae c t i v i t yG: e o l .
Barber,
M e x i c o' a n d
3 9 , 1 8 3 p.
Mines M i n e r aR
l esourcesB
, ull.
B a i l e y , R.K.,
New
Mag.,
-
901.
a n dr e l a t e d
277
-
284.
1 9 7 4 , T h eg e o c h e m i s t r yo fc a r b o n a t i t e sa n dr e l a t e d
C.,
r o c k fsr o m
two
c a r b o n a t i t ce o m p l e x e sS, o u t h
N y a n z aK
, enya:
Lithos,
Barker,F.,
v.
7 , p.
53
-
63.
1 9 5 8 , P r e c a m b r i a na n dT e r t i a r yg e o l o g y
TablQ
a su a d r a n g l e ,
New
M i n e r aR
l e s o u r c e sB
, ull.
B a r k e r , F.
a n d Friedman, I ,
r o c kost fhTe u s aM
s ountains,
New
Mexico:
of
the
M e x iB
c ou r eM
a ui n e s
4 5 , 1 0 p4 .
1974,
P r e c a m b r i amn e t a v o l c a n i c
New M e x i c oM: a j oErl e m e n t s
Las
Page 1 3 7
a n d Oxygen I s o t o p e s :
New
2 5 t hf i e l dc o n f . ,
115
p.
1975,
for
-
Geol.
SoG
c .u, i d e b o o k ,
118.
Sharp, W.N.,
D.R.,
B a r k e rF,W
., ones,
Mexico
a nD
d esborough,
C.A.,
a
T h eP i k e sP e a kb a t h o l i t h ,C o l o r a d oF r o n tR a n g e ,a n d
of
model
the
g a b b r o - a n o r t h o s i t e - s y e n i t e - p o t agsrsasinu
c iitte
v.
PrecambriaR
n esearch,
B a r r e t t , M.E.
New
,
-
D u t c h eCsosu n t y ,
.Bull.,
V.
H.F.,
S t r u c t u r aaln pd e t r o l o g i.cs t u d i eisn
775
Y o rPka,r t
-
Petcal:
G eSoolc. .
11:
Am.,
850.
T r e x l e r , D.T.,
1976,
New
F o r m a t i o n( P r e c a m b r i a n ) T
, a o sC o u n t y ,
New
47, p.
B i n g l e r , E.C.,
160.
126.
1936,
B a r t h , T.F.W.,
-
M e x iG
co
eS
o lo.G
c .u, i d e b o o3k0.,ft h
ield
121
c o n f .p, .
97
1979, D e p o s i t i o n asl y s t e m s
a nK
d irschner,C.E.,
i nt h e. R i n c o n d a
Mexico:
2 , p.
e:
Kemp,
W.R.,
a nBdo n t a m ,
Jr.,
A basic
language
c o m p u t e pr r o g r a m
for
p e t r o l o g icca l c u l a t i o n sN: e v a dB
a u r e aM
u i n easn G
d eology,
p.
R e p o r t2 8 ,2 7
B l a k e s t a d , Jr.,
District,
R.B.,
1976,
S o c o r rCoo u n t y ,
oC
f o l o .a, l s o
o p e n - f i l er e p o r t
G e o l o tg
oh
K
y
fee lM
l yi n i n g
N e w Mexico:
N e w Mexico Bureau
43, 1 4 0 p.
M.S.
t h e s i sU, n i v .
M i n eM
s i n e r aR
l esources,
P a g e 138
H.,
Blatt,
Middleton, G.,
S e d i m e n t a r yR o c k s :
B o n n i c h s e n , W.,
a nM
durray,
R.,
1 9 7 2O, r i g i n
1 9 6 2 ,G e n e r a lA s p e c t so ft h eP r e c a m b r i a nr o c k s
New
Mexico:
New M e x i c oG e o l S
. O C .G
, u i d e b o o k1
, 3 t hF i e l dC o n f . ,
abstr.,
174.
1 9 7 4 , R a d i o m e t r i ca g ed e t e r m i n a t i o n sf r o mt h e
B r o o k i n s , D.G.,
FloridM
a ountains,
Brookins,
D e l l aV a l l e ,
D.G.,
from
t hZ
e u nM
i ountains,
67
-
R . S .a, n dL e e ,
~
671
C.E.,
Sanford,
-
-
1978,
557.
Rb-Sr
P r e c a m b r i asni l i c irco c k s
v.
15,
~ ~~
t ~ hGeol. ~ sot.
Chamberlin, R.M.,
1978,
A.R.,
7 , p.115
Chamberlin,
emplacement
G~~~~~~
R.M.,
special
with
~
Am.,
v.
Bull.,
i
747.
G e o t h e r m aal r e a ,
Publ.
M.J.,
New M e x i c oM
: o u nG
t. eol.,
1959,
A.F.,
r e f e r e n ct e
o
Chapin,
of
555
2 , p.
71.
Buddington,
7 0 , P.
v.
New M e x i c oG: e o l . ,
g e o c h r o n o l o g iicn v e s t i g a t i o n
p.
634 p .
New J e r s e y ,P r e n t i c e - H a l l ,I n c . ,
toL
hfe m i tM
a ro u n t a i nSso, c o rC
r oo u n t y ,
p.
of
E x p l o r a t i oFn r a m e w o r k
New M e x i c o :
-
Osburn, G.R.,
W h i t e , D.R.,
and
of t hS
eocorro
New M e x i cG
o e o lS. O C S
. ,p e c .
129
1978, G e o l o g i c map o tf h eL e m i t a r S, o c o r r o
annodr t h eCrhni p a d eMr ao u n t a i S
n so,c o C
r roou n t y ,
New
~
~
Page 139
Mexico:
of t h eS o c o r r og e o t h e r m a l
i nE x p l o r a t i o nf r a m e w o r k
a r e a , N e w M e x i c o , New M e x i c oB u r e a uM i n e sM i n e r a lR e s o u r c e s ,
88.
o p e n - f i l er e p o r t
C h a m b e r l i n , R.M.,198O,
V o l cCaenSniotcecCro,or ur on t y ,
dissertation,
Condie, K.C.,
G e oSl .O C .
Condie,
p l u t o nfsr o m
-
149.
Condie,
K.C.
131
New
Co'lo.
Mexico:
PhD
S c h o ool f . M i n e s .
1 9 7 3 , A r c h e a nM a g m a t i s ma n dC r u s t a lT h i c k e n i n g :
Am.,
K.C.,
o f S o c o r r oP e a k
i np r e p a r a t i o n ,G e o l o g y
1978,
-
8 4 , 2p 9. 8 1
v.
Bull.,
2992.
G e o c h e m i sP
torrfyo t e r o z ogirca n i t i c
N e w M e x i c o , U.S.A.:
Chem.
A. J.,
Baunddd i n g ,
Geol.,
1979,
V.
p-
21,,
and
Geology
G e o c h e m i s t r y of P r e c a m b r i a nR o c k s ,C e n t r a la n dS o u t h - c e n t r a l
New M e x i c o :
N e w M e x i c oB u r e a uM i n e sM i n e r a lR e s o u r c e s ,
Mem.
3 5 , 58 p.
C u r L i e , K.L.,
Surv.
1976,
Th
a lek a l i n
r oe c k s
of
o f C a n a d aB, u l 2
l .3 92,2 8p8.
C u r r i e , K.L.
J.,
a n dF e r g u s o n ,
1 9 7 1 , A s t u d yo fF e n i t i z a t i o n
around
t h ae l k a l i n ce a r b o n a t i t ce o m p l e x
O n t a r i o , Canada:
Can.
517.
C a n a dGae: o l .
J.
E a rSt h
ci.,
a t C a l l a n d eBr a y ,
V.
8,
p.
498
-
P a g e1 4 0
K,L.
Currie,
and
Ferguson,
fenitization
1 9 7 2 , A s t u d y of
J.,
i nm a f i cr o c k sw i t hs p e c i a lr e f e r e n c et ot h eC a l l a n d e r
c o m p l eC
x :a n .
J.
9 p.
E a r tShc iv. ,.
1 9 6 7 , G e o c h e m i s t r ya n do r i g i n
Dawson, J.B.,
U l t r a m a f i ac n d
Related
R o c k se, d i t o r
Bay
1254
-
1261.
of K i m b e r l i t e s
P.J.
in
W y l l i ep:. 2 6 9
- '
278.
Denison,
far
R.E.
a n dH e t h e r i n g t o n ,
w e sTt e x aasnsdo u t h - c e n t r a l
Cir.
W.R.,
Dickinson,
1970,
104, p.
1
-
InterpretD
i negt r i t a l
G r a y w a caA
knerdk o s e :
9.
695
p.
-
D i c k i n s o n , W.R.
and
Sucezek,
s a n d s t o cnoe m p o s i t i o n :
63, p.
2164
-
D i c k i n s o n , W.R.
C.A.,
Ass.
Am.
82
-
Erickson,
-
1 9 7 9 , P l a t et e c t o n i c sa n d
P eG
t r e. oB
l .u, lvl . ,
2182.
and V a l l o n i , R.,
1 9 8 0P,l a tsee t t i n gasn d
v.
p r o v e n a n c eo sf a n d isnm o d e r no c e a nb a s i n sG
: eology,
p.
of
Modes
S eP4
dev0
.t.., ,
3.
in
New Mexico
New M e x i c o :
B u r e a uM i n e M
s i n e r aR
l esources,
707
1 9 6 9 , B a s e m e nRt o c k s
E.A.,
8,
86.
R.L.
petrology
of
Arkansas:
U.S.
aBnlda d e ,
L.V.,
1963,
t h ae l k a l i icg n e o ucs o m p l e x
Geol.
Surv., P r oPf .a p e4 r2 5 ,
Geochemistry
a t Magnet
Cove,
95 p.
and
Goddard,
E.M.,
T r a s k , P.D.,
Strigewald,
Jr.,
J.T.,
C h a rG
t :e oSl .O C
o .f
Shapiro,
dFe o r d ,
Rove,
R.D.,
R.M.,
a n dO v e r b e c k ,
Am.,
F.S.,
Grpmaldi,
Jr.,
O.N.,
1975, R o c kC o l o r
B o u l d eC
r ,o l o .
L.,
S
an
ch
dn e p f e ,
1966,
M.,
D e t e r m i n a t i o no fc a r b o nd i o x i d ei nl i m e s t o n ea n dd o l o m i t eb y
1966;
a c i d - b a st ei t r a t i o niG
n
: e oS
l .u r vR. e s e a r c h ,
Prof.
G e o lS. u r v . ,
B186
-
~188.
1959, M i n e r a lD e p o s i t si nL i n c o l nC o u n t y ,
G r i s w o l d , G.B.,
Mew
Mexico:
P a p e r 550-B,
U.S.
New
Mexico
Bureau
M i n eM
s i n e r aR
l e s o u r c e sB
, ull.
67, 1 1 7 P.
H a y a t s u , A.,
York, D.,
Significance
of
F a r q u h a r , R.M.,
Rocks:
N a t u r e , v.
of
207, p.
625
-
626.
555 p .
1 9 7P
2 e, t r o l o go
Iy
gf n e o ua snMd e t a m o r p h i c
New York,McGraw-HillBookCo.,
I r v i n e , T.N.
1965,
1966, T hGe e o l o goyCf a r b o n a t i t e sC: h i c a g o ,
R a n dM c N a l l ya n dC o . ,
Hyndman, D.W.,
J.,
strontium
i s o t o prea t i oitsnh e o r i e s
c a r b o n a t i t e genesis:
H e i n r i c h , E.W.,
a n dG i t t i n s , ,
an
Bdu r a g a r ,
C h e m i c a lC l a s s i f i c a t i o n
W.R.A.,
533 p .
1971,
A
guide
of t h e Common V o l c a n i cR o c k s :
to
the
Can.
P a g e1 4 2
J.
v.
EartS
hci.,
8 , p.
523
-
542.
1 9 7 5 , C h e m i c aM
l e t h o d so fR o c kA n a l y s i s :
J e f f e r y , P.G.,
Great
B r i t a i n ,P e r g a m o nP r e s s ,5 2 5p .
1 9 6 8 , G e o l o g yo ft h ea l k a l i n eP r e c a m b r i a nr o c k s
Kelley, V.C.,
a t P a j a r i t oM o u n t a i n O
, t e r oC o u n t y ,
Am.,
Bull.,
Kerr, P.F.,
79, p.
v.
1565
-
N e w M e x i c oG
: e o lS. O C .
1572.
1 9 5 9 , O p t i c aM
l ineralogy:
New
McGraw-Hill
York,
Book Company,442p.
King,
1965,
B.C.,
Metasomatism
W.S.
or
P i t c h ea rn d
Sons, I n c . ,
a n a t e x i s , I n C o n t r o l s o f Metasomatism, e d .
Flinn:
G.W.
p.
217
Kisvarsanyi,
T nh ae t uaro
nerdi gm
oi fn
igmitites:
E.B.,
-
New
Y o rJko, h
Wni l e
ay
nd
234.
1 9G8r0a,nrciiotnim
g
c p l eaxneds
P r e c a m b r i a nh o t - s p o ta c t i v i t yi nt h eS t .F r a n c o i st e r r a n e ,
v.
M i d - c o n t i n e nrte g i o nU, n i t eSd t a t e sG: e o l o g y ,
-
8 , p.
43
47.
L a m b e r t , P.W.,
part
of
Univ.
the
M o nL
t ea r g o
a r e a , N e w Mexico:
M.S.
of t h e
thesis,
of N e w M e x i c o , 9 1 p.
L a s k yS,. G1. ,9 3 2T,h e
Mexico:
1 9 6 1 , P e t r o l o g y o f t h eP r e c a m b r i a nr o c k s
New
Ore D e p o s i t s
of
S o c o r rC
oounty,
M e x i cBo u r e aM
u i n eM
s i n e r aRl e s o u r c e B
s ,u l l .
New
Page 143
8 , 139 P -
1 9 7 4 , C o n t r a s t i n tgy p eosPf r e c a m b r i a gn r a n i t i c
L o n g , P.E.,
i n t h eD i x o n - P e n n a s c oa r e a n, o r t h e r n
rocks
N e w Mexico:
25th f i e l cd o n f . ,
M e x i cG
o e oSl .O CG
. ,u i d e b o o k ,
New
-
101
p.
108.
L o u g h l i n , G.F.
aK
n do s c h m a n ,
D i s t r i c t , New Mexico:
d e p o s i t so ft h eM a g d a l e n aM i n i n g
1 9 6 2M
, etamorphism
itnhSeo u t h e ranl posf
Zealand:
217
-
Nat.
Am.
Hist.
Mus.
New
Bull.,
4 , p.
123, A r t .
247.
1 9 6 8 , Rock a nM
d i n e r aAl n a l y s e s :
Maxwell, J . A . ,
I n t e r s c i e n c eP u b l . ,J o h nW i l e y
R.H.
Mitchell,
a n d Sons,
H.R.,
aKnrdo u s e ,
-
39, p1.5 0 5
584 p.
1975,
S ui lsfoutro p e
Hedge, C . E . ,
Geochronology
3:
U n i t eSdt a t e ps ,a r t
p.
5409
N o c k o l dSs.,R . ,
-
v.
C oA
s .c t a . ,
1513-
Muehlberger, W.R.,
1966,
York,
New
g e o c h e m ci saotrfrbyo n a t i tGe es :o c h i m .
R.F.,
U.S.
168 p .
G e o lS. u r v .P, r o fP. a p e2r 0 0 ,
Mason, B . ,
1 9 4G
2 ,e o l o g
ay
n
od
re
A.H.,
Denison,
of
R.E.,
a nM
darvin,
tm
h ei d - c o n t i n ernetg i o n ,
v.
J o uGr e. o p h yRse. s e a r c h ,
71,
5426.
1954,
A v e r a gCeo m p o s i t i oonf
Some
Igneous
Page
R o c kG
s :e oSl O
. C.
Olson, J.C.,
1977,
and
Am..,
Bull.,
M a r v i nR, . F P
. ,a r k e r ,
Age
mafic
R.L.,
a n dT e c t o n i cs e t t i n g
-
1032.
Mehnert,
and
H.H.,
rock
c as ,r b o n a t i t aetn
sh,do r i v
u emi n s
-
673
687.
B.E.,
Gorman,
Jour.
Su
Grevo. l, .
U.S.
5 , p.
R e s e a r c h , v.
T.H.,
1007
of l o w e P
r a l e o z o i ca l k a l i c
s o u t h - cC
en
o tl roar la d o :
Pearce,
65, p.
v.
144.
a nBde r k e t t ,
1977,
T.C.,
The
r e l a t i o n s h i bp e t w e e m
n a j oerl e m e ncth e m i s t r ayn tde c t o n i c
e n v i r o n m e n t of b a s i ca n di n t e r m e d i a t ev o l c a n i cr o c k s :E a r t h
P e t t i j o h n , F.J.,
a n d Row P u b l . ,
36, p . .
v.
a nP
d l a n e tS. c iL. e t t e r s ,
1 9 5 7 , S e d i m e n t a rRyo c k s :
e x c l u d i n cg a r b o n a t ae n vd o l c a n i sca n d s :
New
of
U.S.
1978, P e t r o l o g ay n C
d hemistry
S a n d Js .: G e o l . ,
Powell, J.L.,
132.
YorH
k ,a r p e r
sandstones
-
G e oS
l .u r v . ,
21 p .
P r o fP. a p e4r 4 0 S ,
P o t t e rP, . E . ,
-
718 p .
1963, C h e m i c aclo m p o s i t i o n
P e t t i j o h nF, . J . ,
121
v.
86, p.
H a r l e y , P.M.,
423
-
CIanr b o n a t i t ee ds ,i t o
T rustatGn
l eidt t i L
n so:n d o n ,
I n t e r s c i e n c eP u b l . ,
p.
365
-
378.
M o d e rR
niver
449.
a nFd a i r b a i r n ,
s t r o n t i u mi s o t o p i cc o m p o s i t i o na n do r i g i n
of
H.W.,
1966,
The
of c a r b o n a t i t e s ,
Page
1894,
P r a t t , J.H.,
silicates:
of
89
R e i n e c k , H.E.
-
a n dS i n g h ,
Environments:
1979,
M.,
the
P r e l i m i n a r ey p o r t :
439 p .
F e n i t i z a t i oonf
59, p .
v.
1
-
a n dG r o e n e v e l d ,
of
e a s t eT
r nr a n s v a aTl r: a n s .
Geol.'
some
23.
D.,
t h ce a r b o n a t i t e
S OSCo. u t h
1954,
The
a t Loolekop,
Africa,
v.
208-
1975,
Schwab,
F.L.,
F r a m e w om
r ki ,n e r a l o agcny
hd,e m i c a l
of c o n t i n e n t am
l a r g i n - t y p sea n d s t o n eG
: eology,
composition
3 , p.
in
i n t h eS e i l a n dP r o v i n c en o r t h e r nN o r w a y :
Hiemstra, S.A.,
-
151.
Siilinjarvi
A
m i n e r a l o g ayn pd e t r o l o g y
V.
-
1973, D e p o s i t i o n a S
l edimentary
N o r s kG
. eologisk
Tidsskrift,
197
149
New Y o r kS, p r i n g e r - V e r l a g ,
m a f i ci g n e o u sr o c k s
57, P.
f e r r o u is r o ni n
92.
I.B.,
a nTdy s s e l a n d ,
R u s s e l l , H.D.,
of
of
e a s t e Fr ni n l a n d ;
3 , p.
V.
48, p .
v.
Sci.,
1969, T h ec a r b o n a t i t e
Precambrian
R o b i n s , B.
J.
Am.
P u u s t i n e n , K.,
Lithos,
O n t h de e t e r m i n a t i o n
145
487
S c h w a r c z , H.P.,
-
490.
1966, C h e m i c a al n dm i n e r a l o g i cv a r i a t i o n si n
a r kqaounsaircdt u
zpirrtioenggr e sr es igvi eo n a l
metamorphism
G:e oSl .O C .
S h a p i r o , L.,
Am.,
1 9 7 5 , R a p i da n a l y s i so f
Bull.,
v.77, p.
509
-
532.
s i l i c a t e , c a r b o n a t e ,a n d
Page
1 9 5 4 , T r a c ee l e m e n t s
Shaw, D . M . ,
i n m e t a m o r p h i cr o c k s ,P a r t
V a r i a t i o ndsu r i nm
g e t a m o r p h i s mG: e o S
l .O C .
6 5 , p.
1151
-
1954,
On
-
Stroud,
-
1967,
Classification
Abhandl.,
R.B.
and
Collins,
1954,
G.E.,
v.
107,
Preliminary
o p erne-pfoi lr et ,
E.R.D.A.
4 2 6 5 , 1 pg.
1 9 8 0 ,i np r e p a r a t i o n ,G e o l o g y
o f t h eW a t e rC a n y o n
Jordo
Cna n y o
a rneSao, c o rC
r oo u n t y ,
M e x i cIon s tM
. i n i nT
ge c h . ,
S u v a , K.,
n o m e n c l a t uor fe
240.
DEC-RRA-1410,
-
and
Mineral.
R e c o n n a iR
s seapnocret :
Sumner, W . ,
v.
I g n e oR
u so c kGs e: oMl .a g . ,
i g n e oruosc kNse: uJeash r b .
144
of
244.
S t r e c k e i s e n , A.,
p.
B u l l - , V.
t hger a p h i c ar el p r e s e n t a t i o n
in
D i f f e r e n t i a t i oTnr e n d s
238
1,
1165.
S i m p s o n , E.S.W.,
91, p.
Am.,
146
O a n a , S.,
Wada, H . ,
New M e x i c o :
M.S.
New
thesis.
anO
d saki,
S.,
1975,
Isotopic
Page 1 4 7
g e o c h e m i s tar p
n
ye
dt r o l o g y
African
of
P h y s i c as n dC h e m i s t r yo tf h eE a r t h ,
7 35
-
e d i t o r sA h r e n s ,
Great B r i t o nP, e r g a m oPn r e s s ,
7456
Jr., Frechen, J.,
T a y l o r , H.P.,
a n dD e g e n s ,
E.T.,
e l n do i s t r i c tS, w e d e n :
West G e r m a n ayn tdhA
Acta.,
v.
Vartiainen,
-
31, 407
p.
H.
1 9 6 7 , Oxygen
from t h eL a a c h e rS e ad i s t r i c t ,
c a r b o ni s o t o p es t u d i e s
and
9,
V.
D a w s o nD, u n c a na ,nEdr l a n k :
P.
c a r b o n a t i t e Is n,
Cos.
Geochem.
430.
aW
nd
oolley,
1976,
A.R.,
TPheet r o l o g y ,
M i n e r a l o gaynC
, dh e m i s ttorh
fyfee n i ttoeh
Sfseo k l i
Geol.
c a r b o n a t i it ne t r u s i o F
n i, n l a n d :
Bull.
280,
Verwoerd, W . J . ,
Finland,
of
87 p.
1 9 6 6 , F e n i t i z a t i o n of b a s i ci g n e o u sr o c k s ,I n
C a r b o n a t i teedsi,tTo ur st t l e
I n t e r s c i e n c e Publ.,
v o nE c k e r m a n n ,
Surv.
,
p.
295
-
G
a ni tdt L
i nosn: d o n ,
308.
H., 1948, The a l k a l i n e d i s t r i c t
o f A l n oI s l a n d :
C a , No.
S v e r i g e s-.G e o l o g i s k a. .~ U n d e r s o k n i n g. ,S e r .
36, 1 7 6
P.
W a t k i n s o n , D.H.
a n dW y l l i e ,
t h ec o m p o s i t i o nj o i n
P.J.,
NaAlSiO4-CaC03-H20
a l k a l ri co c k - c a r b o n a t i ct eo m p l e x e s :
357
-
370.
1 9 7 1 , E x p e r i m e n t a ls t u d y
J.
g e n e s i s of
a n dt h e
Petr.,
of
V.
12,
p.
Page 148
1978, A Rb-Sr Isotope Geochronologic study
White, D.L.,
Precambrianintrusives
south-central
of
New Mexico:
PhD
1976, Petrogenesis of Metamorphic Rocks:
New
of
dissertation, Miami Univ., 147 p.
Winkler, H.G.F.,
York, Springer-Verlag, 334p.
T-M.,
Woodward,
1973, Geology
Socorro County, New Mexico:
M.S.
of
the
LemitarMountains,
New Mexico Inst.
Mining Tech.,
Thesis, 73 p.
Wyllie,
1966, Experimental
studies
P.J.,
problems:Theorigin
and
of
carbonatite
differentiation of carbonatite
magma, in Carbonatites, editors Tuttle and Gittins:
Interscience P u b l . ,
Yardley,
p.
311
-
352.
1978, Genesis
B.W.D.,
London,
of
the
Skagit
gneiss
migmitites, Washington and the distinction between possible
mechanisms of migmitization:
89, p.
941
Yoe, J.H.,
-
Chem., v.
v.
951.
Fritz, 3rd, W.,
determination
Geol.SOC.Am.,Bull.,
of
25, p.
and Black, R.A.,
uranium
with
1200
-
1204.
1953, Colorimetric
dibenzoylmethane:
Anal.
P a g e 149.
APPENDIX A
A N A L Y T I C A L PROCEDURES
S a m p l eP r e p a r a t i o n
a r o c kc r u s ' h e tr os i l t - s i z e
Samplew
s e r ef i r s ct r u s h e di n
i n an automatic
grams o f e a c hs a m p l ew e r eg r o u n d
f r a g m e n t sT
. en
m o r t aarn pd e s t lw
e i t ahc e t o nfeotrh i r t m
y i n u t e sD. u p l i c a t e
b r i q u e t t e sw e r e
made o f e a c hs a m p l ea n ds t a n d a r df o rs u b s e q u e n t
X - r a yf l u o r e s c e n c e .
of
E i g shat m p l e s
as
t hcea r b o n a t i tdei kwe e rper e p a r e d
a b o v e ,x c e pt ht at ht i r tgyr a moesfa csha m p lwe e rues e d .
singb
l er i q u e t t e
was
made
of
A
eac
s ah m pflfoeur t uX
r e- r a y
was d r i e d a t 110
d i f f r a c t i oT
n .hr e m a i n d o
e arf cs ha m p l e
d e g r e e s C.
f o r w e tc h e m i c a la n a l y s e s .
f o ro n eh o u ra n dt h e nu s e d
X - r a yF l u o r e s c e n c e
X-ray
a
fluorescen
dw
ca o
eteabr et a i no end
8 - p o s i t i os n
p e c t r o g r a p( tha b l e
c o l l e c t e df o re a c hb r i q u e t t e .
1).
Ten
Norelco
thousac
no
d u nwt se r e
A s t a n d a r dd r i f tp e l l e t
was
ipno s i t i ofno uotrfhsep e c t r o g r a pahncdo u n t eeda cthi m e .
C o u nrta t efsoera c sha m p laen sdt a n d a r w
d e rde i v i d e bdtyh e
count
r a t e s f o rt h e
d r i f t p e l l e tt oc o r r e c tf o ra n yi n s t r u m e n t a l
kept
Page 150
drift.
A c o m p u t e rp r o g r a m
(J.R.
f o er a c h
briquette
Renaulp
t ,e r s o n aclo m m u n i c a t i o n )T. h e
all
c o u n t i n gs t a t i s t i c sa r eb e t t e rt h a n2 %f o r
Na20
and MgO,
ratio
was e m p l o y e df o rd e t e r m i n i n gt h e
4%.
w h i c ha r eb e t t e rt h a n
e l e m e n t es x c e p t
C a l i b r a t i o nc u r v e sw e r e
a s e c o n dc o m p u t e rp r o g r a m u, s i n g
c o n s t r u c t e d ,e m p l o y i n g
U.S.G.S.
a n di n t r a l a br o c ks t a n d a r d s( t a b l e2 ) .T h ee r r o r sa r es u m m a r i z e d
in table
3.
C h e m i c a lP r o c e d u r e
Mm
a jnieondlroe rm ewn
deterstee r me iongnehdt
c a r b o n as at im
t uepasltieoansm
bg si oc r p tt ii ot rna, t i o n ,
4).
c o l o r i m e t r i ca, n d
gravimetrim
c e t h o d (s t a b l e
was
( h y d r o f l u o r i cd)i s s o l u t i opnr o c e s s
Two
(L.
Fe,
Mg,
Ca,
Na,
f o trh d
eetermination
made;
one
for t h ed e t e c t i o no f
Al,
K , Mn, a n d Zn a n dt h eo t h e rc o n t a i n e dt w og r a m s
of C r , Co,
Cu,
5).
Xi,
Ba,
Sr,
and
Li.
The
a P e r k i n E l m e r 303 o r a V a r i a n 1 2 5 0
s a m p l e sw e r ea n a l y z e du s i n g
s p e c t r o m e t e r( t a b l e
Brandvold,
d i s s o l u t iw
o ne sr e
c o n t a i n e do n eh a l ft oo n eg r a mo fs a m p l e
HF
u s etddoe c o m p o st eh e
s a m p l e sf o rs u b s e q u e n ta t o m i ca b s o r p t i o na n a l y s i s
p e r s ocnoaml m u n i c a t i o n ) .
standard
A
S t a n d a r d sw e r ep r e p a r e df r o ma n a l y t i c a l
grad
r eea g e n tCs a
. l i b r a t i oc n
u r vw
e sedr e t e r m i n ef eodar c h
e l e m e nat n a l y z e dT. h ree l a t i v e r r o r
the
elements.
are w i t h i n 3%;
is within
Some e l e m e n t as n a l y z e d
(such
w h i loet h eerl e m e n t(ss u c h
as
5 % f omr o sotf
as N a ,
K,
Cu
and
and ect.)
Ba)
are
Page 1 5 1
w i t h i n1 0 %
(L.
B r a n d v o l dp, e r s o n a cl o m m u n i c a t i o n ) .
M o d i f i e d t i t r a t i o n p r o c e d u r e s were e m p l o y e d t o d e t e r m i n e
a n d C02 ( t a b l e 41,
gram
a nodnhea l f
analyzed
for
u s i n go n eg r a m
of e a c hs a m p l e
tdoe t e r m i n e
C02.
approximately
analyzed
1%. Two
for
C02
a r e p r o d u c i b i l i t yo f
The r e l a t i v ee r r o r' f o r
is
FeO
were
s t a n d a r d( sl i m e s t o naenddo l o m i t e )
3% t oh fe
awnew
driet h i n
known
C02
from t o t a l
was f o u n d
by
subtracting
Fe203
c o n c e n t r a t i o nF. e 2 0 3
F ed e t e r m i n e db y
t o d e t e r m i n e FeO
D u p l i c a st ea m p l ewse r e
each
s a m p l ae n d
resulted
in
0.3% f o r FeO a n d 1 . 5 % f o r C02.
FeO
atomic a b s o r p t i o n .
V a r i o u sc o l o r i m e t r i cp r o c e d u r e sw e r e m p l o y e dt od e t e r m i n e
U308
T i 0P
22
, 0 a5n, d
4).
f oera csha m p l(et a b l e
4 ) a n dt h e
d e t e r m i n e d by t h ec l a s s i c a lg r a v i m e t r i cm e t h o d( t a b l e
filtrate
w a s u s e tddo e t e r m i n e
from
t h sei l i c da e t e r m i n a t i o n
w a s d e t e r m i n e du s i n g
T i 0 2P.2 0 5
dissolutio
s anm p l e .
One
to
1
-
5 ml.
five
d e c o m p o s e du s i n gn i t r i ca n dp e r c h l o r i ca c i d s
u308
(table
4).
while
the
of t h e
relative
e r r o rf o r
p e r s o n a lc o m m u n i c a t i o n ) .
0.5
gram
BF
sample w a s
g r aem
oafcs h
f o r t h ea n a l y s i so f
A b s o r b a n c e w a s m e a s u r e du s i n g
S p e 2c 0T. h ree l a t i v e r r ofroTr i 0 a2 n P
d205
S i l i c a was
a B a u s c ha n d
was
U308 i s w i t h i n 5% ( L .
within
Lomb
1%,
Brandvold,
Page 1 5 2
TABLE 1
INSTRUMENTAL PARAMETERS FOR X-RAY FLUORESCENCE
ELE TUBE CRYSTAL
Si GYPCr
Ti
Cr
Cr
A1
QTZ
Cr
Fe
GYP Cr Mg
Ca
Cr
K
Cr
Na
Cr
Mn
W
Ba
w
Rb
iF
Mo
L
Mo
Sr
QT Z
GYP
,
FPC
QT Z
QTz
GYP
LiF
LiF
L iF
-
DETECTOR
PATH
PEAK
PEAK 20
FPC
FPC
FPC
FPC
FPC
FPC
FPC
FPC
SCIN
SCIN
SCIN
SCIN
VAC
VA C
VA C
VAC
VAC
VA C
VAC
VA C
AIR
AIR
AIR
AIR
KA 1
KA
KA1
KA
KA
KA
KA
KA 1
KA
LB
KA
KA
26.00
48.70
66.65
33.79
81.32
60.42
68.24
1 0 3 * 35
62.82
78 9 2
26.34
24.85
Flow proportion counter
SCIN - Scintillation counter
VAC
Vacuum
GYP - Gypsum
QTZ - Quartz
LiF - Lithium Fluoride
-
BKGRD 20
65.00
-
80.00
-
102,105
62.2,63.5
78,79-5
25.5,26.8
24,25.5
Page 1 5 3
TABLE 2
ROCK STANDARDS USED FOR X-RAY
STD
Si02
Ti02
A1203
Fe203*
MgO
CaO
K20
Na20
BCR-1
LOSP
BLCR
JB-1
GSP-1
AGV-1
F-3
G-2
JG-1
HI-31
54.5
75.9
55.7
2.20
0.20
0.84
13.6
i3.4
1.81
7 -51
3.46
6.92
0.93
1.70
4.83
3.27
58.8
52.6
.3a. 2
Mn
BCR-1
LOSP
BLCR
JB-1
GSP-1
AGV-1
F-3
G-2
JG-1
HI-31
* -
0.66
1.04
0.84
0.50
0.26
0.88
1.07
2.60
72.2
STD
BR
1.34
67.4
64.8
69.1
BR
W-1
52.1
59.0
w-1
'
FLUORESCENCE
Ba
12.3
16.9
14.5
15.3
17.3
0.07
9.04
5.97
7-70
4.33
0.96
9.21
2.02
4.90
0.22
6.76
6.36
1.53
2.65
2.21
16.7
6.47
15.0
10.2
11.1
12.9
0.76
0.73
4.21
6.62
1.94
14.2
13.3
13.8
20.7
15.4
Rb
-
Sr
1080
-
331
763
.
8.11
-
260
-
1280
-
T o t a l i r o n c a l c u l a t e d as F e 2 0 3 .
2.18
6.50
11.0
1.52
1.42
3.49
3.51
2 - 79
5.53
2.80
4.26
2.89
2.63
-
4.51
3.96
4.07
2.88
0.64
1.40
3.11
2.15
3.05
3.39
Page 154
TABLE 3
ERRORS
ELEMENT
S
Si02
Ti02
A1203
Fe203
MgO
CaO
Na20
K20
0.59
0.4370
0.0206
0.1162
0.2336
9.92
0.0230
00. 6. 090 9 6
20
. 2. 1
40 7 9
0 '.00.27338
B a 2.04
Rb
Sr
Mn
C
RMS$ ERROR
4.66
1.86
4.59
0.80
0.70
5.17
1.77
1.96
3.25
2.81
3.47
11.8
25.49
0.82
;0.58
1.15
7.4
0.85
7 - 25
17-19
7.39
4.45
-
s t a n d a r dd e v i a t i o n
c o e f f i c i e n t o fv a r i a t i o n
RMS$ ERROR - r e l a t i v e e r r o r
S
C
-
= S / m e a nc o m p o s i t i o n
=
x 100
Page 1 5 5
TABLE
SUMMARY
OF
ELEMENT
CHEMICAL PROCEDURES
FOR
ANALYSIS
OF
CARBONATITES
METHOD
REFERENCE
Jeffery,
1 9 6 8 , 323
p.
1 9 7 5 , p. 35
Jeffery,
1 9 6 8 , p . 379
1 9 7 5 , p . 470
S i 0g2r a v i m e t r M
i ca x w e l l ,
T i 0c2o l o r i m e t r iM
c axwell,
FeO
4
-
-
332;
39, 470
-
'471'
381;
471
1 9 7 5 , 2 P8p 1r. a; t t ,
t i t r a t i Joenf f e r y ,
c 0t i2t r a t i oJ en f f e r y , ,
-
1894
1 9 7 5 , p. 64 - 6 6 ; S h a p i r o ,
1 9 7 5 ; G r i m a l d i ,S h a p i r o ,a n d
1966
Schnepfe,
~ 2 50
c o l o r i m e t r i Jc e f f e r y ,
1 9 7 5 , p.
LO1
NOTE:
g r a v i m e t r iJce f f e r y1,9 7 2p2,.7 0
L O 1 = l o s s o ni g n i t i o n
-
U308
c o l o r i m e t r imc o d i f i efdr o Y
m o eF ,r i t za ,nBdl a c k ,
382
-
385
CO2
1953
A l , t o t a l F e , Mg, Ca, Mg, K , Mn, C r , Co, N i ,
a n d Cu w e r ed e t e r m i n e db ya t o m i ca b s o r p t i o n .
S r , B a , L i , Zn,
TABLE 5
ATOMIC ABSORPTION INSTRUMENTAL
PARAMETERS
ELEMENT WAVELEIiGTH
A1
Fe
Mg
Ca
Na
K
Mn
C r
co
'
N i
Sr
Ba
L i
Zn
cu
* -
3100
2494
2862
2122
2950
3838
2805
3584
2412
2369
2350
5542
3394
2152
3254
STANDARDS, ppm
10
2
.1
0-5
0.5
0.5
0.5
1
0.5
1
0.5
10
0.5
0.5
0.5
-
-
--
-
200
15
2.0
5
5
5
10
10
15
15
10
50
10
2.0
5
a - N 2 0 a: c e t y l e n e - n i t r o u so x i d e
a-a:
a i r - a c e t y l e n e flame
FLAME
INSTRUMENT
a-N20
a-a
a-a
a-a
a-a
a-a
a-a
a-a
a-a
a-a
a-a
a-N20
a-a
a-a
a-a
V a r i a n 1250
P e r k i n E l m e r3 0 3
P e r k i n E l m e r3 0 3
P e r k i n E l m e r3 0 3
P e r k i n E l m e r 303
P e r k i n E l m e r 303
P e r k i n E l m e r3 0 3
V a r i a n 1250
P e r k i n E l m e r3 0 3
P e r k i n E l m e r 303
P e r k i n E l m e r 303
V a r i a n 1250
P e r k i nE l m e r3 0 3
P e r k i n E l m e r 303
Varian1250
flame,
APPENDIX B
BRIEF PETROLOGIC DESCRIPTIONS OF THE ANALYZED R O C K SAMPLES
SEDIMENTS
Lem 4 0 1 A
, r k o s eL
, o w e rU n i t :
a d a r k - g r a y ,v e r yf i n e - g r a i n e dr o c k
w i tm
h i n ofro l i a t i o (nr e l i cbt e d d i n g )R. e l i csta n gd r a i nas r e
v e r yp o o r l ys o r t e d v
, e r yf i n es a n d - s i z e ' dw i t ha v e r a g er o u n d n e s s
a n sdp h e r e c i t yP. o s s i b l ge r a d e b
dedding
may e x i slto c a l l yT. h e
r o c cko n s i s tos f
a fine-grained
m a t r i x ( p r o b a b l sye r i c i t ae n d
(lO-l5%),
q u a r t z3 ,5 - 4 0 % q) ,u a r t( z3 0 - 3 5 2 1u ,n t w i n n efde l d s p a r
g r e e nb i o t i t e( 5 - 1 0 % ) ,m a g n e t i t e
( < 5 % ) , a n dm u s c o v i t e( 5 - 1 0 % ) .
L e m 5 2 4M
, e d i u m - g r a i n eA
d r k o s eU, p p eUr n i t :
a pinkish-gray
to
d a r k - g r am
y ,e d i u m - g r a i n er o
d cwki st h
t r o nf o
g l i a t i oR
n .e l i c t
sand
grains
a r e p o o r l ys o r t e d f, i n e t- o
medium-sand
s i z ew i t h
m o d e r a t er o u n d n e s sa n dv a r i a b l es p h . e r e c i t y .T h er o c kc o n s i s t so f
q u(a3r0t -z 3a5l$t p
e) ,lr ae g
di o c l a s e ,
An50
(20-25%),
fine-grained
matrix
( p r o b a sbel ryi c i1t0e -, 1 5 %
mu
) ,s c o v i t e
(10-20%d
) ,a rgkr e etbnor o wbni o t i t(ep a r t i a l layl t e r etdo
c h l o r i t e s ,5 - 1 0 % ) ,m a g n e t i t e
( 5 % ) a n d a t r a c ea m o u n to fg a r n e t .
Lem 5F2 i5n, e - g r a i nAerdk oUs ep ,U
p enri t :
a
dark-gray
f i n e - g r a i n e dr o c kw i t hs t r o n gf o l i a t i o n .R e l i c ts a n dg r a i n sa r e
p o o rsl oy r t efdi ,n e - s a sn idz w
e divt a
h r i a brloeu n d n easns d
T hr eo ccko n s i s otqsfu a r (t z2 5 - 3 0 %u) ,n t w i n n e d
spherecity.
f e l d s(p2a5r - 3 0 f%i n) ,e - g r a i n e d
matrix
(probab
s el yr i c i t e ,
2 0 - 2 5 b$ i) o, t (i pt ea r t i a al l yt ecrtheoldo r i1t e5 ,- 2 0 % ) ,
m u s c o v i t e ( 5 % ) , a n dm a g n e t i t e
((1%).
a
,
Lem 5 2 3M, e d i u m - g r a i n eA
d r k o s eU, p p e r
Unit:
a pinkish-gray
to
d a r k - g r afyi ,n e - g r a i n se ldi g h tfloyl i a t reodcRk e. l iscatn d
graina
s r ep o o r -l ys o r t e d f. i n e t- om e d i u m - s a n ds i z e dw i t h
fair
r o u n d n e S s a n ds p h e r e c i t y .G r a d e db e d d i n gc a nb ed e t e c t e di nt h i n
o f q u a r t z( 5 0 - 6 0 $ ) ,p l a g i o c l a s e ,
An70
T h er o c kc o n s i s t s
section
,
g
r
e
e
n
b
i
o
t
i
t
(
e
1
0
1
5
%
)
p
,
e
r
t
h
i
t
i
K
c
f
e
l
d
s
p
a
(
r
5
1
0
%
)
,
(20-25$ 1
(<5%).
m a g n e t i t e ( 4 5 % ) , a n dm u s c o v i t e
Lem 526 S u b a r k o U
a m e d i u m - g r faiyn,e - g r a i n e d ,
s ep, pUenr i t :
g r a i n s a r ew e l l - s o r t e d ,m e d i u m - s a n d
m a s s i v e r o cRke. l iscatn d
k o n s i s tosf
s i z e w i t h g o ordo u n d n e sasnsdp h e r e c i t yT. hreo cC
(70-80%),
p e r t h i tKi c- f e l d s p(a5r- 1 0 %p)l,a g i o c l a s e ,
quartz
( 5 - 1 0b%
i o)(t,5i -t e1 0m%u)s, c o (v5i -t e1 0a%
n d) ,
An20-40
magnetite (<5%).
a p i n k i s h - g r atm
yo e d i u m - g r a y ,
Lem 5 2 0 ,S u b a r k o s e ,U p p e rU n i t :
R e l i c t s a ngdr a i nasrf ea i r l y
f i n e - g r a i n efdo,l i a treodc k .
s i z ewdi ft ahrior u n d n e as ns d
t o medium-sand
sorted, fines p h e r e c i t y .T h i nl a m i n a t i o n s
of a r k o s i ct os u b a r k o s i cl e n s e sc a n
bd e t e c t e
ti hndsi n
e c t i o nTs .hr oe c ko n s i s t s
of q u a r t z
( 7 0 - 8 0 % ) , g r e ebni o t i (t 5
e - 1 0 $p) e, r t h i t K
i c- f e l d s p a r
(lo%),
( < 5 % ) , a nfdi n e - g r a i n e d
u n t w i n n epdl a g i o c l a s(e< 5 % m
),uscovite
m a t r i x ( p r o b a b l ys e r i c i t e ,
<%5).
MAFIC DIKES
a p o r p h y r i t i c ,g r e e n i s h - g r a y ,f i n e - g r a i n e d
Lem 5 6 , D i a b a s ed i k e :
u n m e t a m o r p h o sreodccokn s i s t p
ionl fag g i o c l a(sael t e rteod
(<5%), chlorite
c a l c i t e( 4
, 0 - 4 5 %h
) ,o r n b l e n d(e3 5 - 4 0 1b ,i o t i t e
( < 5 % ) , m a g n e t i t e( 5 - 1 0 % ) a, n d
a t r a c e a m o u not qf u a r t zO
. phitic
t e x t u r e is w e l l preserved.
d1 a, d
f iick e :
a dark-gb
rtaloay cvke,r y
Lem 1 5 a5n2M
f i n e - g r a i nm
e da,s s ri o
vc ceokn s i sgt o
ir neh
fg
eonr n b l e n d e
( 3 5 - 4 0 %f e) ,l d s p a r ,
An50
( 3 0 - 3 5 2g1r ,eaebnnrdo w
b ino t i t e
( p a r t i a l l ya l t e r e dt oc h l o r i t e ,1 0 - 2 0 $ ) ,m a g n e t i t e( 5 - 1 0 % ) ,a n d
t r a c ea m o u n t
o f q u a r t z .S l i g h tf o l i a t i o nc a nb ed e t e c t e d
section.
a
i n thin
Lem 4 0 7a n d5 0 2M
, a f i cd i k e :
a b l a c k ,a p h a n i t i cr o c kc o n s i s t i n g
of
grh
e eo nr n b l e n
( 4d0e - 4 5 %
p l )a,g i o c l a s e ,
An50
(40-4521,
m a g n e t i t e( 5 - 1 0 % ) ) ,b r o w nb i o t i t e( p a r t i a l l ya l t e r e dt oc h l o r i t e ,
<b%),
a n d a t r aa cmeo u n t
of
q u a rO
t zp. h i t ei cx t u r e
is
preserved.
Some o
t hp
f el a g i o c l a s e
i s s l i g h t rl y
e p l a c ebdy
c a r b o n a t ea n ds e r i c i t e .
L E M I T A RD I O R I T E / G A B B R O
Lem 1 4 8 , 4 3 9 , 5 0 1a, n 5
d 0 3D
, iorite/gabbro:
a w h i t ea n db l a c k ,
s p e c k l ecdo, a r s e - g r a i n reodcc ok n s i s t ido
nafgbr lku e - g r e e n
h o r n b l e n d e( 3 0 - 4 0 % ) ,a l t e r e dp l a g i o c l a s e ,
An40-55 ( 3 0 - 4 0 % ) b
, rown
a ngdr e ebni o t i t(e1 5 - 2 0 % )m, a g n e t i t e
( 5 % ) , quartz ( < 5 % ) ,and
a n d g a r n eSt .u b o p h i t it co
t r a ca em o u n o
at sp
f a t i t se p, h e n e ,
o p h ti et ixct u r e
is
p r e s e rF
cvaoienadd
er. s- e - g r a i n e d
i n c l u s i o n sc a nb ef o u n dw i t h i nt h ec e n t r a lp a r to ft h ep l u t o n .
Q u adr it oz r i t e :
a b lw
aa nchd
ksi tpee,c k l e d ,
Lern 4 4 9 ,
m e d i u m - g r a i n reodc o
k n s i s t i gn
org
fe h
en
o r n b l e n (d2e5 - 3 0 % ) ,
b r o wa nngdr e ebni o t i (t 2
e 5 - 3 0 %a) l, t e r epdl a g i o c l a s e ,
An50
K
f
e
l
d
s
p
a
r
(
5
7%),
c
r
u
s
h
e
d
quartz
(7-10%), p e r t h i t i c
(2O-25%),
of
a p a t i at en d
t rda ac m
e ounts
corroded magnetite (5-7%), an
garnet.
T hqeu a r at zngda r n oe ft t ef n
orm
inclusions i n t h e
b i o t i t e .T h eK - f e l d s p a r
i s o f t e nz o n e da n da l t e r e dt o
sericite.
Subophitictexture i s preserved.
Lem 5 3 2 F, e n i t i z e dd i o r i t e l g a b b r o :
a p i n ka n db l a c ks, p e c k l e d ,
c o a r s e - g r a i n e dr o c kc o n s i s t i n g
of d a r k g r e e n a n d
b r o w nh o r n b l e n d e
( 3 5 - 4 0 2 1 ,a l t e r e dp l a g i o c l a s e ,
An5-15 ( 4 0 - 4 5 2 1 ,m a g n e t i t e( 2 - 3 2 1 ,
h e m a t i t e( 1 - 2 % ) ,a n dq u a r t z( 5 - 1 0 2 ) .
L e m 533, F e n i t i z e dd i o r i t e l g a b b r o :
a p i n ka n db l a c ks, p e c k l e d ,
o f g r e eannbdr o whno r n b l e n d e
c o a r s e - g r a i n erdo ccko n s i s t i n g
( 4 0 - 4 5p2l1a,g i o c l a s e ,
An15
( 4 0 - 4 5p$e)r,t h iKt i- cf e l d s p a r
( 5 - 1 0 2 1q ,u a r t(z5 - 1 0 2 1a ,n d
a t r a c e amount o f m a g n e t i taen d
zircon.
G R A N I T I C ROCKS
Lem 5 0 , G n e i s s i c g r a n i t e :
a p i n k i s h - g r a y t o medium-gray,mediumto
c o a r s e - g r a i n e df,o l i a t e d
r o c kM
. o r t atre x t u r e
i s developed.
Th
r oe c k
o n s i s tqosuf, a r(t3z 0 - 3 5 %K) ,- f e l d s p(a2r 5 - 3 0 2 1 ,
p l a g i o c l a s e( 2 0 - 2 5 2 1 ,g r e e nb i o t i t e( 1 0 - 1 5 $ ) ,a n dh e m a t i t e
(<5%).
a pinkish-gray
to
medium-gray,
Lern 55,
G n e i s s gi cr a n i t e :
c o n s i s t s qouf a r t z
m e d i u m - g r a i n ef d
o ,l i a treodcTkrho
. ec k
( 3 0 - 3 5 % ) , ' K - f e l d s p( a2 r5 - 3 0 %
p )l a, g i o c l a s~en,6 0 -(7205 - 3 0 2 1 ,
g r e e na n db r o w nb i o t i t e( p a r t i a l l ya l t e r e d
t o c h l o r i t e ,l 0 - 1 5 % ) ,
a n d a t r a c e a m o u not hf e m a t i t e ,
m a g n e t i t e a, n d
disseminated
fluorite.
'
~
aranite:
a p a l e - r eadnbdl a c k ,
mediumt o
Lern 8 4 , P o l v a d e rG
c o a r s e - g r a i n e rdo c k
c o n s i s t i no
gqf u a r t (z3 0 - 3 5 2 1p, e r t h i t i c
K - f e l d s p a r( 3 0 - 3 5 2 1 ,p l a g i o c l a s e( 2 5 - 3 0 2 1 ,b r o w nb i o t i t e( 5 - 1 0 % ) ,
A mortar
a n d t r a c e a m o u n t s of h o r n b l e n d e ,g a r n e t ,a n dm a g n e t i t e .
texture is oftenpreserved.
~
Polvadera Granite:
a m o d e r aotrea nagbnelda c k ,
Lern 511,
c o a r s e - g r a i n er d
o cc ko n s i s t i no
qgfu a r (t 3
z 0 - 3 5 %p) e, r t h i t i c
(partially
K - f e l d s p(a3r0 - 3 5 2p1l,a g i o c l a(s2e5 - 3 0 $b)i,o t i t e
a l t e r e dt oc h l o r i t e ,5 - 1 0 2 1 ,a n d
t r a c e a m o u n t s of m a g n e t i t ea n d
A s u b m o r t a rt e x t u r e
i s preserved.
garnet.
Lern 447A, L e u c o g r a n i t e :
a w h i t ea n db l a c kc, o a r s e - g r a i n e dr o c k
- "of--equal-a-mou.nts--of- ~quar-t-z
,-perthitic-K-f e l d s p a r ,--and
cons-is-t-%nx
plagioclase,
An40,
and
t r a c e a m o u nbotifso t i(t<e5a$n) d
m a g n e t i t e( < X % ) .
a
g r a y i s h - pt oi n k
L e m 1M
0 8u,s c o v i t e - b i o g
t irtaen i t e :
medium-gray,
f i n e - g r a i n e d ,s l i g h t l yf o l i a t e dr o c k ,c o n s i s t i n go f
'
P a g e1 6 0
, q u a r t z( 3 0 - 3 5 % ) ,p e r t h i t i cK - f e l d s p a r( 2 5 - 3 0 % ) ,p l a g i o c l a s e ,
An40
( 2 0 - 2 5 %g) ,r e ebni o t i t e
(lo%), m u s c o v i t e
( 5 % ) , a nmda g n e t i t e
(<3%).
L e m 1 2M
6 , u s c o v i t e - b i o t i gt er a n i t e :
a
g r a y i s h - p i ntl k
o
ight
g r a yf,i n e - g r a i n e dp, o r p h y r i t i rco c ck o n s i s t i n ogpf l a g i o c l a s e
(30-35
q2
u(1
a2r,5t z- 3 0K%- f) e, l d (s2p0a -r 2 5m%a )g,n e t i t e
3 - 5 % ) , brown b i o t i t(e2 - 3 % )m, u s c o v i t e
( a l t e r e tdloe u c o x e n e ,
a t r a c e a m o u noztfi r c o nG. r a n o p h y r itce x t u r e
( 2 - 3 % )a,n d
preserved.
Lem 4 2 3 P
, o r p h y r i t i cm u s c o v i t e - b i o t i t eg r a n i t e :
b r o w n i s h - g r apyo, r p h y r i tm
i ce d i u m - g r a i n er od ccko, n s i s t i n g
q u a r( t3z5 - 4 0 %p)e,r t h i tKi c- f e l d s p(a2r5 - 3 0 %p)l ,a g i o c l a s e ,
A n 4 0 - 6( 20 0 - 2 5 %b)i,o t i(t5e - 1 0 %m
) ,u s c o v i t e
of
m a g n eht ei tm
eg,ahratoeni retdn
en,b l e n d e .
amounts
G r a n o p h y r i ct e x t u r e i s p r e s e r v e d .
a yellowish-
is
to
of
( 5 % ) , a nt dr a c e
L e m 2 0 3 ,B i o t i t eg r a n i t e :
a light-graym
, e d i u m - g r a i n e d s, l i g h t l y
f o l i a t e dr o c k c, o n s i s t i n go q
f u a r t z( 2 5 - 3 0 % ) p, l a g i o c l a s e ,
An50
(lo%), a n dm a g n e t i t e
( 3 0 - , 3 5 % ) ,K - f e l d s p a r( 2 5 - 3 0 % ) ,b r o w nb i o t i t e
(<5%).
L e m 3 0 2B, i o t i tge r a n i t e :
a g r a y i s h - r e dm, e d i u m - g r a i n erdo c k ,
of
p e r t h i t iKc - f e l d s p a( 2
r 5 - 3 0 % q) ,u a r t z
(25-30461,
consisting
p l a g i o c l a s e , An40 ( 2 5 - 3 0 % ) b, r o w nb i o t i t e( 5 - 1 0 % ) a, n dm a g n e t i t e
(5%)G
. r a n o p h y r i ct e x t u r e
i s preserved.
a
m e d i u m -m
g readyi ,u m - g r a i n e d ,
Lem 438,
B i o t i gt er a n i t e :
b i o t i t e - r i crho c kT. h irso ccko n s i s tospfl a g i o c l a s e ,
An40-50
( 4 5 - 5 0 %q)u, a r(t 2z 0 - 2 5 5b1r, o wbni o t i(t 1e 0 - 1 5 %K) ,- f e l d s p a r
was taken
( 1 0 - 1 5 % ) a, n dm a g n e t i t ea n dh e m a t i t e( < 2 % ) T
. h i sr o c k
n e at rhbeo u n d a rbye t w e etnh e
Lemitar
d i o r i t e j g a b b r ao n tdh e
a l t e r e d f a c i e s o ft h eP o l v a d e r aG r a n i t e .
CARBONATITES
Lem 34024
572
,5aP
70
n
, rb0
di,m
, sai rl y
icocarbonates:
m e d i u m - g r a i n e dg,r aty
bor o w np,o r p h y r i t irco ccko n s i s t i nogf
c a r b o n a t e m a t r i x ( d o l o m i t ce a, l c i 6t e0 - 8 0 %a) p, a t i (t 5
e-10%),
o p a q u e(sm a g n e t i t5e - 1 0 % )r ,o c fkr a g m e n t(s0 - 1 5 % )d, i s s e m i n a t e d
f l u o r i t e( < 5 $ ) ,
brown b i o t i t ea n dp h l o g o p i t e( 5 - 1 5 % ) a, n dt r a c e
of
q u a r t fze, l d s p ahr e, m a t i t ae n,hdo r n b l e n d O
e .f t e n
amounts
l a r greo c k
f r a g m e n t s ( 1 -i 2n c h e s
in
d i a m e t e ra)rter a p p e d
t h e s ed i k e s T
. h e s er o c k sa r ev e r yh e t e r o g e n e o u s o
, f t e nl a y e r e d ,
s h o w i n g r e l i c t c r y s t a l sr e p l a c e db yc a r b o n a t ef l u i d s .I n d i v i d u a l
c r y s t a l s a rceo r r o d eadncdr a c k ew
d i tcha r b o n a t e ' r e p l a c e m e n t .
in
Page 1 6 1
Igneou
t es x t u r essu, c h
as a b s o r p t i o n ,
a r e p r e v e l a nSt o. v i t e
v e i nosf t ecnr o s s c upth e n o c r y s tasnxde n o l i t h s( S
. a m p l e4s2 7 a
5-6 f e eat p a rat l o n g
a n4d2 7 b
come f r o m
t hsea mdei k ea,b o u t
strike.)
Lern 5 0 6 R
, e p l a c e m e n st i l i c o c a r b o n a t i t e l: a y e r e d m
, edium-grained,
g r a y t o b r o w np, o r p h y r i t i c
rock
consisting
o cf a r b o n a t e
matrix
a trace
(70-75561, m a g n e t i (t 1
e 0 - 1 5 %s) e, r i c i (t 1
e 0 - 1 5 %a) n, d
a m o u notbf i o t i t eS. u b o p h i t i tce x t u r e
i s p r e s e r v e dS. o v i t ae n d
h e m a t i t ev e i n l e t sc r o s s c u tt h er o c k .
Lem 5 3
R0e,p l a c e m es inlti c o c a r b o n a t ift ien: e - g r a i n e
gd
r a, y ,
p o r p h y r i t i cr o c kc o n s i s t i n go cf a r b o n a t e
m a t r i x ( 5 0 - 6 0 % )g, r e e n
(10-15%),
a nbdr o wbni o t i at encdh l o r i (t 2
e 0 - 2 5 %m
) ,a g n e t i t e
hematite
( 5 % ) , q u a r t(z1 - 2 % )a,n d
a t r a caem o u n t
of f e l d s p a r .
R e l i c ts u b o p h i t i ca n dp o r p h y r i t i ct e x t u r e sa r ep r e s e r v e d .
L e m 531a a n 5
d 3 1 bA, n k e r i t i rca u h a u g i t e :
a f i n e - g r a i n e db, r o w n
r o c kc o n s i s t i n g
o f c o a r s ec a r b o n a t e
( 8 0 - 9 0 % ) , m a g n e t i t e( 2 - 1 0 % ) ,
h e m a t i t (e5 - 1 0 % )a, n d
a t r a c e amount
of
b i o t i t ea n dc h l o r i t e .
. ( B o t hs a m p l e s
a r e f r o mt h es a m ed i k e ,a b o u t
s i x f e e ta p a r ta l o n g
strike.
DESCRIPTION OF R O C K SAMPLES NOT ANALYSED F O R CHEMISTRY
Quartzite:
Lem 3 ,
f i n e - g r a i nreodc k .
fine-sandsizedwith
consisto
s qf u a r t z
a tnrdaacm
e ounts
f i n e - g r a i n e dm a t r i x .
a
p i n k im
s he-d
tgoiruam
y - gvrearyy,
R e l i cs ta ngdr a i nasrw
e e l l - s o r t e dv,e r y
g oroodu n d n eassnspdh e r e c i tTyrh.oec k
(>so%), K-feldspar ( < 5 % ) ,p l a g i o c l a s e
of b i o t i tme a, g n e t i tme u
, s c o v i taen, d
(<5%),
Lem 5 2 2 ,G r e e nc h l o r i t es c h i s t :
a f o l i a t e d ,g r a y i s ho l i v eg r e e n ,
f i n e - g r a i n e dm
, i c a e o urso c kT. h reo c ck o n s i s toscf h l o r i t e
b i o t i t e( 4 0 - 5 0 % ) p, l a g i o c l a s e ,
An40-50 ( 2 5 - 3 0 % )q, u a r t (z5 - 1 0 % ) ,
a n dm a g n e t i t e( 5 - 1 0 % ) .
a
and
Page
APPENDIX C
CHEMICAL
ANALYSES*
SEDIMENTS
Lem 401 Lem 524
Si02
77- 8
0.54
Ti02
A1203
11.1
4.57
Fe203*
MgO
0.94
1.39 CaO
2.45
Na20
2.91 K20
0.07 MnO
TOTAL101.77
512
1172
Mn
Ba
Rb
Sr
*
-
69.6
0.72
14.6
6.09
1.54
1.05
2-53
4.03
62.0
0.72
18.6
7-52
1.54
0.20
65.2
0-75
17-3
76.5
73.8
0.65
13.9
5-05
1.37
1.39
2.54
3.79
4.48
0.59
12.4
4.42
1.03
2.65
2.86
2.22
100.24
0.06
98.03
0.07
99.73
102.75
102.56
490
892
303
577
.139
600
1140
203
78
144
87
592
1534
164
237
1376
161
162
0.08
1.76
5.63
6.66
1.38
1.06
2.83
995
244
163
0.07
0.08
548
Total iron expressedas Fe203.
$, elements expressed inppm.
Oxides expressed in weight
. .
162
MAFIC DIKES
120
Lem 56
Lem 1 5
Lem 407
Lem 5 0 2
Lem 5 2 1
Si02
Ti02
A1203
Fe203*
MgO
CaO
Na20
K20
MnO
TOTAL
49.8
1.58
11.7
14.7
5.78
47.8
1-77
46.9
1.85
45.0
12.0
12.1
15-9
15.7
9.37
9.44
10.2
20.9
6.32
4.52
48.0
2.38
11.2
0.26
0.25
96.95
98.11
Mn
Ba
Rb
Sr
2011
1936
333
334
1549
375
45
35
99
24
122
9.27
2.28
1.58
8.00
10.0
1.68
0.71
1.85
2.05
0.60
0.19
98.20
1.75
4.37
0.35
95 * 2 6
2677
397
119
98
16.9
7.31
9-69
1.92
0.67
0.22
98.29
1698
341
56
108
CIPW Norms
or
ab
an
di
hY
01
4.2
9.3
14.2
19.3
1 7 . 1 2 2 . 02 3 . 1
mt
4.9
il
3.0
0.3
2 4 . 0 20.421.9
19.7
25-5
0.9
Q
or
ab
an
c
di
-
5.3
3.4
orthoclase
albite
anorthite
corundum
diopside
-
3.5
25.8
4.0
17-3
14.8
7.1
16.2
23.3
24.4
13.3
12.8
0.1
24.2
5.3
3.5
7.0
3.5
5.6
4.5
14.2
-
il
mt
01
Q
hy
-
-
-
ilmenite
magnetite
olivine
quartz
hypersthene
19.8
-
0.6
LEMITAR D I O R I T E / G A B B R O
Lem 1 4 8
54.5 51.2
Si02
2.88
Ti02
A1203
11.1
Fe203"
18.2
3.08
MgO
CaO
7.63
1.73
Na20 2.83 2.43
K20
1.50
Lem 449
Lem 501
Lem 5 0 3
59.1
12.1
51.0
2.29
9.26
17.7
21.1
51.0
2.99
10.6
18.6
3.12
7.43
Lern 439
1.46
2.58
7.97
1.01
6.10
1.17
11.8
15.9
0.98
5.34
2.53
2.43
1.50
2.03
0.32
97 * 7 6
99 * 17
1.65
0.27
98.09
2538
404
44
86
2448
329
52
185
2063
366
49
89
Q 9.7
17.3
or
12.0
21.4
14.7
6.2
9.8
20.6
13.2
10.3
20.2
16.7
5.3
17.0
6.2
5.7
Mn 0
TOTAL
1.90
0.19 0.33 0.31
9 8 . 92 71
*91
1502
386
35
176
Mn
Ba
Rb
Sr
2395
346
55
214
.
CIPW Norms
9.1
ab
an
di
hy
mt
il
6.4
8.9
20.6 14.6
14.7 15.0
19-5
17.4
6.1
5.5
11.2
8.9
23.9
13.7
17.0
5.9
2.8
13.1
22.8
18.5
7.0
4.3
2.2
LEMITAR DIORITE/GABBRO
-
continued
Lem 532 Lem 533
Si02
54.2
Ti02
1.17
13.1
A1203
11.8
Fe203* 17.0
MgO
2.94
CaO
4.30
Ma20
3.75
K20
TOTAL
Rb
Sr
1.19
96.35
58.9
1.30
12.2
2.06
4.42
3.16
2.00
97-14
82
41
745
211
.
CIPW Norms
Q
or
ab
an
di
hy
mt
il
8.8
7.0
31.7
11.9
8.0
19-77
5.7
2.2
16.6
11.8
26.7
15.6
5.4
13.4
4.1
2.5
.
Page 166
G R A N I T I C ROCKS
f
f
Si02
Ti02
A1203
Fe203"
Lem 5 0
L e m 55
L e m 84
Lem 5 1 1
70.1
0.73
69s.5
0.85
12.2
12.1
73.3
0.43
13.0
5.00
73.8
0.48
13.3
3.86
0.49
0.93
3.05
5.35
0.06
CaO
Na20
K20
7.06
0.94
1.90
3.06
4 ..17
MnO
0.10
MgO
TOTAL
Mn
Ba
Rb
Sr
100.26
806
946
173
105
9.04
0.91
2.06
0.40
1.14
3.01
3.01
3.52
5.05
0. og
0.11
101.10
848
686
101.32
L e m 447A
74.1
0.50
13.8
3.86
0.60
1.51
3.89
3.72
0.06
102.04
445
1378
242
78
434
1415
-
31.9
32.1
0.8
20.8
31.6
25.8
4.6
0.7
22.0
120
115
208
154
Lern 108
73.1
0.56
14.6
3.57
0.79
0.99
2.74
4.59
0.06
101.00
422
1248
191
85
CIPW Norms
Q
C
or
ab
an
di
hY
mt
il
29.4
-
24.6
25-9
7.2
1.8
5.5
3.8
1.4
30.6
25.5
9-2
0.9
7.2
4.9
1.6
35.5
3.3
27.1
32.9
7.5
23.2
-
4.9
3.3
3.5
2.1
2.1
3.0
3.7
1.9
-
0.9
-
1.1
G R A N I T I C ROCKS
si02
Rb.
Sr
continued
Lem 1 2 6
Lem 4 2 3
Lem 203
Lem 302
L e m 438
74.0
75.6
0.39
70.6
0.94
2.89
66.5
0.77
13.9
6.46
66.9
0.64
16.0
5.54
0.40
1.20
0.44
Ti02
A1203 13.1
Fe203* 4 . 5 2
0.22
MgO
CaO
1.38
Na20
4.83
K20
3.25
0.03
MnO
TOTAL 1 0 1 . 7 7
Mn
Ba
-
228
1248
70
68
13.2
0.83
2.78
5.37
0.05
101.51
98.44
349
1342
244
59
808
892
139
190
35.8
1.3
31.7
23.5
21.6
0.3
24.2
32.7
7.7
1-55
3.86
4.10
0.10
13.1
7.39
0.66
1.62
3.39
4.10
0.08
101.88
589
1.30
2.91
3.81
3.63
0.09
100.82
108
107
693
880
174
382
28.9
21.3
690
CIPW Norms
Q
C
or
ab
4.5
29.5
-
19.2
40.9
4.1
an
di
hy
2.1
2.1
mt
2.5
-
2.5
1-5
-
6.6
3.5
0.1
24.2
28.7
8.0
5:6
4.0
-
21.5
32.2
14.0
0.3
6.2
3.0
P a g e 168
CARBONATITE DIKES
Lem 305
Si02
Ti02
A1203
Fe203
FeO
MgO
CaO
.Na20
K20
MnO
c02
P20 5
Lem 427a
21.45
2-75
5.44
8.92
24.5
0 .:70
1.45
0.53
22.66
3.26
4.19
LO1
TOTAL
CARBONATITE DIKES
Lem 5 3 0
Si02
Ti02
A1203
Fe203
FeO
MgO
CaO
Na20
K20
MnO
c02
P205
LO1
TOTAL
-
27.93
1-79
5.54
9.58
6.36
3.70
17.5
0.02
0.83
0.40
17.40
1.59
.3.47
96.11
-
10.89
0.28
2.61
19.11
0.13
2.14
3.57
3.73
4.28
5.27
9.67
9.53
31.6
30.9
0.19
0.47
0.67
29.01
3.47
1.46
99.77
101.30
Lem 506
11.57
11.20
0.40
2.44
3.50
4.22
10.10
32.5
0.19
0.22
0.72
29.10
3.72
1.13
4.32
L e m 500
Lem 427b
1.05
97-12
0.20
4.35
5-78
7.38
9.90
17.8
1.13
0.41
0.37
0.65
26.31
18.14
3.33
3.95
98.93
1.47
88.81
2.20
0.30
1.05
continued
L e m 531a
3.20
L e m 531b
3.59
<o. 1 0
0.46
0.49
0.51
2.23
12.0
7.64
3.86
11.51
6.47
30.2
0.01
0.10
0.47
27.1
0.01
0.10
0.49
36.65
34.85
0.06
0.07
4.67
97.84
4.11
-
93 11
-
L o s s on i g n i t i o n
C02; i n c l u d e s H20,F,
C 1 , and
othervolatiles.
NOTE:
S e eA p p e n d i x A f o r a n a l y t i c a lp r o c e d u r e s .
LO1
. .
CARBONATITE DIKES
..?.
Lem
r
-
Mn
Cr
co
Ni
Sr
Ba
Li
Zn
cu
U
~30846
410
560
520
500
20
10
24
10
42
30
51
38
33
298
1262
84
158
1170
244
18
116
20
7.2
0.0023
Lem
L i
Zn
cu
U
U308%
continued
305 Lern 427a Lern 427b Lem 500 Lem 506
10
10.3
.
CARBONATITE DIKES
Mn
Cr
co
Ni
Sr
Ba
-
0.0033
-
60
322
1516
20
133
9.8
5.9
0.0019
continued
530 L e m 531a Lem 531b
400
398
97
390
177
1779
19
397
26
3.4
0.0011
470
25
56
48
136
3658
7.4
436
24
5.0
0.0016
490
5
52
70
123
652
6-5
619
2-5
4.4
0.0014
230
64
34
31
31
183
534
3200
61
323
1226
20
125
13
11.2
0.0036
154
100
13.4
0.0045
This thesis is accepted
on behalf of the facultyof the
Institute by the following committee:
."
-
'IGURE 2- PRECAMBRIAN GEOLOGY OF THE LEMITAR MOUNTAINS
A
\
+4-+ ++4-++r+ + + +
++
c+
iiii
+
+++++
i+ + + + + + i
+ +++
+ + + + + + + + + + + + + + +
+ + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +
+++
4-
+++
i
c + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +
+ + + + + 3 0 + + + + + + + + + + + + 2 9
+ + + + + + + + + + + + + + + +
+ + + + + + + + + + - I - + + +
+ + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + +
+ + + + + + + +
+ + + + + + f + + + + +
+ + + + + + + + + + + + +
+ + + i+ f
+ ++
+
+
+ + +
+ + + + + + + + + + + +
tiif
+ + + + + + + +
+ + + c + + +
_ . . . . . . .
T
T
M I - C R O W A V ET O W E R
I
I
T
T
T
+ + + + + + + + + +
+
+
t34
07
+
+
+ + + + + + + + + +
I + c + i + +/+"
+ + + + + + + + + + +,0449
+ + + + + + + + +,/0447A
+ + + + + + + +A
i+ + + + + ,
+ + + + + + + + /
i +
+ + + + + i
,c + + + + + /
'
+
+
+
+
+
+
i
f
.MAP A R E A
+
I
P O L V A D E RGAR A N I T E
ALTEREDPOLVADERAGRANITE
B I O T I T EG R A N I T E
MUSCOVITE
T I S
T2
- BIOTITE
GRANITE
G N E I S S I CG R A N I T E
$
+."i
LOWER
UNIT
0
LOCATION
-
CORKSCREWCANYON
520-5
a
OF SAMPLES
ROADS
f
5
8
401
N
T
+
RIW
+
GEOLOGY B Y
T M C L E M O R E . 1980. T WOODWARD. 1973