G e o l o g y of t h e T e n m i l e H i l l 7.5' Q u a d r a n g l e ,
S o c o r r oC o u n t y ,
N e w Mexico
by
C h a r l e s A. F e r g u s o n
J u n e , 1988
N e w MexicoBureau
o f Minesand
O p e n - F i l eR e p o r t
M i n e r a lR e s o u r c e s
283
TABLE O F CONTENTS
................................................
........................................................
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.
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Acknowledgements
Location
Geologic
Setting
Stratigraphy
Pre-Mt
withington Cauldron Units
Kt Withington Cauldron unite
S o u t h CanyonTuff
C a u l d r o n - f i l lU n i t s
U n i t s ............................
Post-Mt W i t h i n g t oCn a u l d r o n
T u f f of T u r k e y S p r i n g s
P o p o t o s aF o r m a t i o n
Quaternary
S t r u c t u r a lG e o l o g y
s y n - v o l c a n i cS t r u c t u r e s
Peak Tuff
S t r u c t u r e s Related t o t h e V i c k s
S t r u c t u r e o f t h e M t Withington Cauldron
Basin and Range Faulting
The Least P r i n c i p a l S t r e s s D i r e c t i o n
Fault
Patterns
M a g n iEt uxdt e n as ni odonfD u r a t i o n
Neotectonics
Economic Geology
References
.
.
......................................
1
1
2
3
3
4
5
7
a
8
.........................................
10
................................................
11
12
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12
..................
12
. .....................................
...................11 45
....................... 15
.............................................
16
........................
16
...............................................
18
...............................................
..................................................... 18
20
ACKNOWLEDGMENTS
T e n m i l e H i l l q u a d r a n g l e i s a p r o d u c to f
T h e g e o l o g i c map o f t h e
two s e p a r a t em a p p i n gp r o j e c t s .
s o u t ha n d
The s o u t h w e s tc o r n e r( e v e r y t h i n g
west o f sec. 3 , T 6 S f R5W) was mapped d u r i n g t h e summer
and f a l l o f1 9 8 3
a s p a r to f
a Master's T h e s i s a t New Mexico
T h e r e s t was
I n s t i t u t e o fM i n i n ga n dT e c h n o l o g y( F e r g u s o n 1
, 986).
mapped d u r i n g t h e s p r i n ga n df a l lo f1 9 8 6
p r o j e c t .B o t hp r o j e c t s
as p a r to f
were f u n d e db y
an independent
t h e N e w MexicoBureauof
M i n e s a n dM i n e r a lR e s o u r c e s .
I would l i k et oa c k n o w l e d g eR o b e r tO s b u r nf o ri n s t i g a t i n gt h i s
w o r k rf o rw o r k i n g
a s t h ep r i n c i p a la d v i s o r
on t h e t h e s i s , a n df o r
h i s d i s c u s s i o n sa n de n c o u r a g e m e n td u r i n gb o t hp r o j e c t s .D a v i d
t h e t h e s i sc o m m i t t e e .C h a r l e s
J o h n s o na n dP h i l i pK y l es e r v e do n
C h a p i nc r i t i c a l l yr e v i e w e d
t h e map.
R i c h a r dC h a m b e r l i nr e v i e w e d
t o DaveLoveandRichard
t h e map and t h i s t e x t .A d d i t i o n a lt h a n k s
I w o u l da l s ol i k et ot h a n k
L o z i n s k yf o rh e l p f u ld i s c u s s i o n s .
F l e t c h e r T i g n e r( p o s t h u m o u s l y ) ,
W i l s o n ,a n dB u c kW i l s o nf o r
L u c i l l e T i g n e r l Buddy T i g n e r ,A r c h
t h e i r hospitality.
LOCATION
The T e n m i l e H i l l 7.5'
C o u n t yo nt h e
q u a d r a n g l e i s l o c a t e di ns o u t h w e s tS o c o r r o
west s i d eo fM i l l i g a nG u l c h ,
a 15 km w i d eh a l fg r a b e n
s e p a r a t i n gt w on o r t h - t r e n d i n gb a s i na n dr a n g eu p l i f t s( M a g d a l e n a
a n dS a nM a t e oR a n g e s ) T
. o p o g r a p h yo ft h eq u a d r a n g l e
b y a p e d i m e n t s u r f a c e s l o p i n go f ft h e
MateoMountains.
is dominated
e a s t e r n f o o t h i l l so ft h eS a n
T h r e e m a j o re a s t - f l o w i n gd r a i n a g e s( f r o mn o r t ht o
1
s o u t h :B i gR o s aC a n y o n ,R o s e d a l eC a n y o n ,a n dN o r t hC a n y o n )d i s s e c t
t h ep e d i m e n ts u r f a c e ,a n de v e n t u a l l y
feed i n t o t h e s o u t h e a s t -
of t h e h a l f
a x i a l f l u v i a ls y s t e m
f l o w i n gM i l l i g a nG u l c h ,t h e
graben.
E l e v a t i o n s i n t h e q u a d r a n g l er a n g ef r o m5 , 6 0 0 ’
c o r n e rt o7 , 4 0 0 ‘
i n t h e southeast
o nH o r s eM o u n t a i ni nt h es o u t h w e s tc o r n e r .
Vegetation is d o m i n a t e db yh i g hp r a i r i eg r a s s e sw i t hs c a t t e r e d
s t a n d so f
s h e l t e r e d areas.
w h i t e o a k ,j u n i p e r ,a n dp i n o np i n ei n
A t h i g h e re l e v a t i o n s ,s c r u bo a k ,m o u n t a i nm a h o g a n ya n ds t a n d so f
p o n d e r o s ap i n ec a n
be f o u n d .
GEOLOGIC SETTING
T h e map a r e a i s i n t h e n o r t h e a s t e r nM o g o l l o n - D a t i lv o l c a n i c
f i e l d , a m i d d l eT e r t i a r y
much o fs o u t h w e s t
s t r a t i g r a p h yo f
C h a p i n ,1 9 8 3 ) ,a n d
mass o f c a l c - a l k a l i n e r o c k t h a t b l a n k e t s
New Mexico.
t h e v o l c a n i c f i e l d , t h e D a t i l G r o u p( O s b u r na n d
a youngerunnamedsequence.The
a v o l c a n i c l a s t i cs e q u e n c ew i t h
a s h - f l o wt u f f s .
Two s e q u e n c e sc o m p r i s et h e
some mafic l a v a sa n dm i n o r
The y o u n g e rs e q u e n c e
d i s t r i b u t e dv o l u m i n o u s
D a t i l Group i s
silicic
i s d o m i n a t e db yf i v ew i d e l y
s i l i c i c a s h - f l o wt u f f s( o l d e s tt oy o u n g e s t :
Hells Mesa T u f f , La J e n c i a T u f f ,V i c k sp e a kT u f f ,
Lemitar T u f f , a n d
S o u t hC a n y o nT u f fO
: s b u r na n dC h a p i n1, 9 8 3 )H
. igh-precision
40Ar/39Ar
relative error
27.36
sheets w i t h
s a n i d i n ed a t e so ft h e s ea s h - f l o wt u f f
-
of +0.15
Ma are: 32.04,28.78,28.46,27.97,and
M
a ( M c I n t o s ha n do t h e r s ,1 9 8 6 ) .R e l a t i v e l ym i n o rv o l u m e s
o t h e rr o c k( b a s a l t i ca n d e s i t el a v a s ,r h y o l i t el a v a s
v o l c a n i c l a s t i c s )o c c u rl o c a l l yt h r o u g h o u t
2
a n d t u f f s , and
t h e y o u n g e rs e q u e n c e ,
f o r e a c ho f
a r em o s t l yr e l a t e dt os o u r c ec a u l d r o n s
of
t h e m a j o rt u f f
and
units.
M i o c e n ea n dy o u n g e r o c k so ft h eS a n t a
F e Group,
a m2stly
the
s e d i m e n t a r ys e q u e n c ew i t hm i n o rb i m o d a lv o l c a n i c s ,o v e r l i e
y o u n g e rv o l c a n i cs e q u e n c e .
Tenmile H i l l q u a d r a n g l e i s d o m i n a t e db y
The s t r a t i g r a p h y o f t h e
t u f f u n i t s o f t h e y o u n g e rv o l c a n i c
t h e f i v e m a j o ra s h - f l o w
a r e e x p o s e d i n n e a r b ya r e a st ot h e
s e q u e n c e .D a t i lG r o u pr o c k s
s o u t h( A t w o o d ,
1982),
a n dp r e s u m a b l yo c c u r
i n t h es u b s u r f a c e .
t h e S a n t aF e
l o w e r m o s tp a r to ft h eP o p o t o s aF o r m a t i o n( b a s eo f
Group) i s p r e s e n ti nt h en o r t h e r n
p a r t of t h eq u a d r a n g l e .
T h e T e n m i l e H i l l q u a d r a n g l e i s b i s e c t e db y
o ft h e
Mt.
t h e s o u t h e a s tm a r g i n
W i t h i n g t o nC a u l d r o n( D e a l1 9 7 3 ) ,s o u r c eo f
r e g i o n a la s h - f l o w
The
the yomgest
t u f f i n t h e S o c o r r o a r e a , t h e S o u t h CanyonTuff
( O s b u r na n dF e r g u s o n1, 9 8 6F: e r g u s o n1, 9 8 6 ) .
t r u n c a t e s o u t f l o ws h e e t s
tuffs
of t h e f o u r o l d e s t r e g i o n a l a s h - f l o w
p a r t o ft h eq u a d r a n g l e .
w h i c h c r o po u ti nt h es o u t h e r n
S t r u c t u r a l l y ,s t r a t a
The c a u l d r o nm , s r g i n
i n t h eT e n m i l e
Hill q u a d r a n g l e a r e t i l t e d
t o t h e e a s t , a n db r o k e ni n t om o s t l yn o r t h - s o u t ht r e n d i n gn o r m a l
f a u l t b l o c k s .R e g i o n a le x t e n s i o n
RioGrande
i s r e l a t e dt of o r m a t i o no ft h e
R i f t ( C h a p i n ,1 9 7 9 ) .
STRATIGRAPHY
PRE-MT.
W I T H I N G T O N CAULDRON UNITS
t u f f s with a
O u t f l o w s h e e t s o f t h e f o u ro l d e s tr e g i o n a la s h - f l o w
c o m b i n e dt h i c k n e s so f5 0 0t o9 0 0
area p r i o r t o f o r m a t i o n o f t h e
m p r o b a b l yc o v e r e dt h e
Mt.
W i t h i n g t o nc a u l d r o n .
P e t r o g r a p h i c a l l y , t h e o l d e s ta n dy o u n g e s to ft h e s e
a n dL e m i t a rT u f f s )
e n t i r e map
( t h e Hells Mesa
are c r y s t a l - r i c hq u a r t z ,s a n i d i n e ,p l a g i o c l a s e ,
3
units.
a n db i o t i t eb e a r i n g
These u n i t s c o n t r a s ts h a r p l yw i t ht h e
c r y s t a l - p o o rs a n i d i n eb e a r i n g
a l l o f the t u f f sa r es u m m a r i z e db yo s b x r na n d
P e t r o g r a p h i cd a t af o r
C h a p i n( 1 9 8 3 b ) .
La J e n c i aa n dV i c k sp e a kT u f f s .
t h e t u f f s (except
More d e t a i l e dd e s c r i p t i o n so f
t h e H e l l s Mesa) i n t h i s a r e a a r e p r e s e n t e di nF e r g u s o n( 1 9 8 6 ) .
two u n i t s ( H e l l s Mesal La J e n c i a
S o u r c ec a u l d r o n sf o rt h eo l d e s t
T u f f s ) a r e i n t h e M a g d a l e n aM o u n t a i n st o
in
u n i t s a r e s p a r i n g l ye x p o s e d
( O s b u r na n dC h a p i n 1, 9 8 3 b ) T
. hese
t h e q u a d r a n g l e ( n e v e r t o g e t h e r )w h e r et h e y
t h e s o u t h e r np a r to f
bothatleast
t h e e a s t a n dn o r t h e a s t
are
200 m t h i c k .
was e r u p t e df r o m
The V i c k sP e a kT u f f
i n t h e s o u t h e r nS a nM a t e oM o u n t a i n s
t h e western p a r t o f
t h e N o g a lC a n y o nc a u l d r o n
(Deal a n dR h o d e s1, 9 7 6 ) .
In
t h e map a r e a t h e V i c k s P e a k t h i c k e n s r a p i d l y t o
t h e s o u t h( t o w a r d sE a s t
Red Canyon)from
0 t o a t l e a s t 300 m
( F e r g u s o n 1, 9 8 6 ) .
t h e Lemitar T u f f i s n o t p r e s e n t l y d e f i n e d ,
A s o u r c ec a u l d r o nf o r
i n t h e MagdalenaMountains.
b u t i s t h o u g h tt ob e
c e n t r a l SanMateoMountains,
m t o morethan200
m.
Lemitar T u f ft h i c k e n se a s t w a r df r o m
T h e Lemitar T u f fa l s o
t h e s e i s e x p o s e d i n t h e NE/4,
s e c . 28,T6S,
The e a s t wall
R5W ( P l a t e
1).
T h e o n l yo t h e rO l i g o c e n eu n i ti nt h e
the Mt.
W i t h i n g t o nc a u l d r o n ,
map a r e a , n o t r e l a t e d t o
i s a b a s a l t i ca n d e s i t el a v af l o wb e l o w
t h e La J e n c i a T u f f t h a t p r e s u m a b l y o v e r l i e s t h e
MT.
H e l l s Mesa T u f f .
W I T A I N G T O N CAULDRON UNITS
The M t .
W i t h i n g t o nc a u l d r o n
was o r i g i n a l l y d e f i n e d b y D e a l
4
20
f i l l s s e v e r a le a s t -
t h i s area.
d i r e c t e dp a l e o c a n y o n s( F e r g u s o n 1
, 9 8 6 )i n
o fo n eo f
I n t h e east-
( 1 9 7 3 )a s
a c i r c u l a rs t r u c t u r ee n c o m p a s s i n g
t h e SanMateoMountains,and
T u f fa n d
A-L
t h e s o u r c eo ft w ou n i t s( P o t a t o
P e a kT u f f )w h o s e
Canyon
names are now c o n s i d e r e d o b s o l e t e
. s b u r na n dF e r g u s o n( 1 9 8 6 r) e d e f i n e d
Osburn a n d C h a p i n1, 9 8 3 )O
Mt.
a NE-SW
W i t h i n g t o nc a u l d r o na s
the
e l o n g a t es t r u c t u r ee x t e n d i n g
from t h e n o r t h e a s tS a nM a t e oM o u n t a i n sa c r o s sM i l l i g a nG u l c ht o
western M a g d a l e n aM o u n t a i n s( F i g u r e
the
l), and a s t h es o u r c eo ft h e
T u f f which i s a t l e a s t 8 0 0
SouthCanyon
of
t h e e n t i r e n o r t he n d
m thickin
t h e cauldron.
S o u t h CanyonTuff
is a c r y s t a l - p o o r
The S o u t hC a n y o nT u f f
t o moderately-cryatal-
r i c h r h y o l i t ea s h - f l o wt u f fc o n t a i n i n gp h e n o c r y s t so fm o s t l y
s a n i d i n e a n dq u a r t z
i n r a t i o sr a n g i n gf r o m
1:l t o 2 : l .
It a l s o
c o n t a i n s a s much a s 2% p l a g i o c l a s ea n dm i n o rt ot r a c ea m o u n t so f
b i o t i t e ,s p h e n e ,
a n d o p a q u em i n e r a l s( F e r g u s o n 1, 9 8 6 ) P. h e n o c r y s t
c o n t e n ti n c r e a s e su p w a r dg r a d u a l l yf r o m
t h e t o po f
t h e u n i tc o n t a i n s
2% t o 2 5 % .
m o r et h a n
I n some a r e a s ,
35% p h e n o c r y s t s .
I n t h e T e n m i l e B i l l q u a d r a n g l e ,t h es t r u c t u r a lm a r g i no ft h e
W i t h i n g t o nc a u l d r o n
i s a c o m p l e xm o n o c l i n a ls a go v e r l a i nw i t h
a n g u l a ru n c o n f o r m i t yb y
CanyonTuff.
a n o r t h w a r d - t h i c k e n i n gw e d g eo fS o u t h
Near t h e c a u l d r o nm a r g i n ,d i s c o n t i n u o u s
t h r o u g h o u t t h e S o u t hC a n y o nT u f f( m a p p e ds e p a r a t e l yo n
The maximum s i z e o f l i t h i c f r a g m e n t s i n t h e
200 cm t o 70 cm t o w a r d st h e
lenses o f
100 m t h i c k o c c u r v e r t i c a l l y
c l a s t - s u p p o r t e dl i t h i cb r e c c i a s1 0t o
a r e t h o u g h tt o
Mt.
Plate 1).
b r e c c i a s decreases f r o m
c e n t e r of t h e c a u l d r o n .
The b r e c c i a s
be c o - i g n i m b r i t el a g - f a l ld e p o s i t s( W r i g h t
W a l k e r ,1 9 7 7 )a s s o c i a t e dw i t h
t h e c o l l a p s eo fn e a r b ye r u p t i o n
c o l u m n ( s )d u r i n ge r u p t i o no ft h eS o u t h
Canyon T u f f .
5
and
rl
New M e x i c o
N
4
I
5
0
IO
15
20
km
t
L
r
l
"
-
5
0
IO
15 m i
F i g u r e 1. Map o ft h en o r t h e r n
San M a t e oM o u n t a i n sa n dM a q d a l e n a
o f t h e M t . W i t h i n q t o nc a u l d r o r
M o u n t a i n ss h o w i n at h el o c a t i o n
m a r g i nf r o m
d e t a i l e d m a p p i n q( s o l i d
l i n e ) , and i n f e r r e d ( d o t t e d ) .
R e c t a n a u l a ra r e ar e p r e s e n t sa r e ao f ' t h e
T e n m i l e H i l l 7.5'
auadrangle.
6
The S o u t h C a n y o n T u f f c o n t a i n s e l o n g a t e p r e f e r e n t i a l l y o r i e n t e d
a n df l o w - b a n d e dp u m i c ef r a g m e n t sc o n s i s t e n t l yo r i e n t e d
a p p r o x i m a t e l y E-W
( 0 7 5 Oa z i m u t h )t h r o u g h o u t h ec a u l d r o n .
A?
e x c e p t i o n i s a n a r r o w b e l t (2-3 km w i d e ) a l o n gt h es o u t h e a s te d g e
o ft h ec a u l d r o n
r e f l e c t i o no f
w h e r e a z i m u t h sa r eo r i e n t e d
NW-SE,
probably a
t h e g e n t l yn o r t h w e s t - s l o p i n gs u r f a c eb u r i e db y
the
S o u t h Canyon h e r e .
C a u l d r o n - f i l lU n i t s
w i t h i n a n da l o n g
Rocks t h a ta c c u m u l a t e d
W i t h i n g t o nc a u l d r o n
i n c l u d er h y o l i t e
t h e m a r g i no ft h e
Mt.
a f t e r e m p l a c e m e n to ft h eS o u t hC a n y o nT u f f
t h e u n i to fE a s t
d o m e sa n da s s o c i a t e dl a v a s ,a n d
Red Canyon ( F e r g u s o n ,1 9 8 6 ) ,
a s e q u e n c eo fv o l c a n i c l a s t i c
f a n g l o m e r a t e sa n ds a n d s t o n e s .
R h y o l i t ei n t r u s i o n s ,
some o f w h i c h may s e a l v e n t s f o r
t h e South
Canyon T u f f ( F e r g u s o n a n d O s b u r n ,1 9 8 6 ) ,a r ec o n c e n t r a t e da l o n gt h e
t h e cauldronM
. o s to f
s t r u c t u r a lm a r g i no f
t h e s e r h y o l i t el a v a s
5% and 1 0 % p h e n o c r y s t so ff e l d s p a e r( s a n i d i n ea n d
c o n t a i nb e t w e e n
p l a g i o c l a s e )a n dq u a r t z
w i t h t r a c ea m o u n t so fb i o t i t e ,s p h e n e ,
a m p h i b o l e , a n d o p a q u em i n e r a l s .
One e x c e p t i o n i s t h e r h y o l i t e on
W i l d c a tP e a kw h i c hd o e sn o tc o n t a i nq u a r t zp h e n o c r y s t s .
C h e m i c a l l y ,t h e s e
l e a s t7 7 %
a r e h i g h - s i l i c a ,h i g h - p o t a s s i u mr h y o l i t e sw i t ha t
S i 0 2 and 4.5% K20 ( F e r g u s o n ,1 9 8 6 ,
The u n i to f
p.
82)
E a s t Red Canyon c o n s i s t s o f a s much a s 200 m of
v o l c a n i c l a s t i cr o c k s ,t h a to c c u ra l o n g
W i t h i n g t o nc a u l d r o n A
. long
t h e i n s i d ee d g eo ft h e
t h e m a r g i n , t h e u n i tc o n t a i n sc o a r s e
c o n g l o m e r a t e sa n dd e b r i s - f l o wd e p o s i t s
p r o x i m a la l l u v i a lf a nd e p o s i t s .
t h a t are i n t e r p r e t e d as
The c o a r s ed e p o s i t sa r ed o m i n a t e d
7
Mt.
l a v a domes
b yc l a s t so fr h y o l i t el a v ad e r i v e df r o mt h en u m e r o u s
t h a t o c c u ra l o n g
crystal-rich
t h e c a u l d r o nm a r g i n .
t u f f , w h i c h a p p e a r s t o b eS o u t hC a n y o n ,a n df a r t h e r
a r e common.
s o u t hc l a s t so fV i c k sP e a kT u f f
unweldedash-flow
Minor l i t h i c - r i c h
t u f f s a r ei n t e r b e d d e dw i t hs e d i m e n t sa l o n gt h e
t h e r h y o l i t e domes.
m a r g i n ,a n da r ep r o b a b l yp r o d u c t so f
northwest,
O t h e r c l a s t si n c l u d e
t h e u n i t g r a d e si n t o
medium-
To t h e
t ot h i c k - b e d d e dt a b u l a r -
p l a n a rc r o s s - s t r a t i f i e ds a n d s t o n e s ,i n t e r p r e t e da se o l i a n .
P a l e o c u r r e n ts t u d i e so f
t h e e o l i a ns a n d s t o n e s( F e r g u s o n ,1 9 8 6 )
i n d i c a t en o r t h e a s t e r l yt r a n s p o r ts u g g e s t i n g
t h es o u t h w e s t .
a s e d i m e n ts o u r c et o
T h e u n i t a s a w h o l er e p r e s e n t s
a l l u v i a l - f a n c o m p l e xt h a ti n t e r f i n g e r sw i t h
t h a t may h a v eb l a n k e t e d
a l a r g ep a r to f
a northwest-d!rected
an i n t r a c a l d e r a e r g
t h e c a u l d r o nf l o o r .
The
b a s i n ' s western e d g e i s a s y n - d e p o s i t i o n a ld o w n - t o - t h e - w e s tf a u l t
w i t h a d i s p l a c e m e n to fa b o u t
Canyon j u s t s o u t h w e s to f
POST-MT.
200 m w h e r e i t i s e x p o s e d i n E a s t Red
t h e map a r e a( F e r g u s o n ,1 9 8 6 ) .
W I T H I N G T O N CAULDRON UNITS
T u f fo fT u r k e yS p r i n g s
The t u f f o fT u r k e yS p r i n g s
i s a c r y s t a l - p o o rt om o d e r a t e l y A l o w e ru n w e l d e da n du p p e r
c r y s t a l - r i c hr h y o l i t ea s h - f l o wt u f f .
welded member c o m p r i s e a s i m p l e c o o l i n g u n i t t h a t
t h i c k i n t h e map area.
f o r m e r 5 t o 15 m t h i c k .
Theunwelded
i s 100 t o 1 6 0
member is a d i s t i n c t i v e c l i f f -
I t g r a d e su p w a r di n t ot h ew e l d e d
i n w h i c hp h e n o c r y s ta n dp u m i c ep e r c e n t a g e si n c r e a s eu p w a r d( 5 - 2 0 %
and2-15%
r e s p e c t i v e l y )P e t r o g r a p h i c a l l y ,
t h e u n i tc o n t a i n s
s u b e q u a la m o u n t so fs a n i d i n ea n dq u a r t z ,m i n o rp l a g i o c l a s e ,a n d
a
m
member,
t r a c e s o fb i o t i t e s, p h e n e a, n do p a q u em i n e r a l s .
v e r t i c a lm i n e r a l o g i c a l
and t e x t u r a lv a r i a t i o n s
are e s s e n t i a l l y
of t h e S o u t hC a n y o nT u f f( F e r g u s o n ,
i d e n t i c a lt oo u t f l o ws e q u e n c e s
1986), w h i c h e x p l a i n s
The u n i t ' s
why t h e u n i t was o r i g i n a l l y c o r r e l a t e d w i t h
Deal ( 1 9 7 3 ) map?ed i t
t h eS o u t h
Canyon
by
t h r e ep r e v i o u sw o r k e r s .
asPotato
Canyon ( S o u t h Canyon e q u i v a l e n t :O s b u r n ,a n dc h a p i n ,
i t a s SouthCanyon.
1 9 8 3 ) 1 Donze(1980)andFerguson(1985)mapped
The t u f f of T u r k e yS p r i n g s
Canyon i n t h e f i e l d o n l yb y
i s d i s t i n g u i s h e df r o m
t h e South
i t s s t r a t i g r a p h i cp o s i t i o n .
It a l s o
h a s a d i s t i n c t l y d i f f e r e n t p a l e o m a g n e t i cp o l ep o s i t i o n ,a n dh i g h p r e c i s i o n 40Ar/39Ar
make i t a b o u t 3 Ma y o u n g e r
d a t e s f r o ms a n i d i n e
t h a n t h e S o u t hC a n y o n( M c I n t o s h ,p e r s o n a lc o m m u n i c a t i o n ) .
t h e unwelded member o f t h e t u f f o f T u r k e yS p r i n g s
J u s tb e l o w
a 20 t o 4 0
m t h i c ki n t e r v a lw i t h i nt h eu n i to f
is
East Red Canyonof
a s h - f a l lt u f fb e d si n t e r l a y e r e dw i t hm a s s i v ep e b b l ys a n d s t o n e s .I n
t h en o r t h e r n
T e n m i l e Rill q u a d r a n g l e t h i s i n t e r v a l c o n a t i n s 3 t o 5
t h i n - b e d d e d ,w e l l - s o r t e d ,m o s t l yc o a r s ea s h rt u f fs e q u e n c e s
2.0 m t h i c k .F a r t h e rs o u t h w e s t ,i nt h eE a s t
Red Canyon a r e a l t h e r e
a r e a s many a s 10 o f t h e s e t u f f s e q u e n c e s t h a t
c o a r s e rg r a i n e d( t y p i c a l l yl a p i l l is i z e ) .
i n t e r p r e t e dt o
be
0.3 t o
are t h i c k e r ,a n d
T h e t u f f sa r e
f a l l o u td e p o s i t sf r o mp l i n i a ne r u p t i o n st h a t
p r e c e d e de m p l a c e m e n to ft h et u f fo fT u r k e yS p r i n g s .
A s o u r c ef o r
t h e T u r k e yS p r i n g s
h a s n o ty e tb e e ni d e n t i f i e d .
i s i t s t h i c k e s t , 160 m w i t h n oe x p o s e dt o p ,
Its known a r e a l d i s t r i b u t i o n e x t e n d s n o r t h a n d
c a n y o nt on o r t h e r nM i l l i g a nG u l c ha n d
MountainsS
. o u t ha n d
It
i n East Red Canyon.
e a s t f r o mE a s t
Red
t h e w e s t e r nM a g d a l e n a
west o f East Red Canyon, i t e x t e n d si n t ot h e
San Mate0 M o u n t a i n s( M c I n t o s h !
n o r t h e r nB l a c kR a n g ea n ds o u t h w e s t
p e r s o n a cl o m m u n i c a t i o n ) A
. s s u m i n ga na v e r a g et h i c k n e s so f1 0 0
9
m
overthis
NE-SW
e l o n g a t e d area g i v e s a v o l u m eo fa b o u t1 0 0k n 2 .
P o p o t o s aF o r m a t i o n
The t u f fo fT u r k e yS p r i n g s ,w h i c hp r e d a t e s
t h e b e g i n n i n go f
the
M i o c e n eb ya b o u t5 0 0 , 0 0 0y e a r s( M c I n t o s h ,p e r s o n a lc o m m u n i c a t i o n ) ,
i s o v e r l a i nb y
t h e P o p o t o s aF o r m a t i o n .
The Popotosa is a seapence
o fv o l c a n i c l a s t i cs e d i m e n t a r yr o c k st h a ta l s oi n c l u d e s
u n i t s : a b a s a l t i ca n d e s i t e
ash-flow
tuffs.
t h e yo c c u r
two v o l c a n i c
l a v a , a n d some b e d d e du n w e l d e dr h - l o l i t e
A l l t h r e el i t h o l o g i e s
a r e mapped s e p a r a t e l y w h e r e
i n t h e n o r t h e r np a r to ft h eq u a d .
T h e s e d i m e n t s( 0t o
6 5 m ) a r e d o m i n a t e db yp e b b l ys a n d s t o n e sa n dc o n g l o m e r a t e s ,a n d
v i r t u a l l yv o i do fc l a y - s i z e dp a r t i c l e s .
s t r a t i f i e d , commonly i n medium-bedded
They a r ea l s o
well-
cross-stratified
sets,
s u g g e s t i n g a b r a i d e df l u v i a ld e p o s i t i o n a ls e t t i n g .S c a n t y
f o r e s e t s , a r ee a s t - d i r e c t e d .
p a l e o c u r r e n td i r e c t i o n s ,f r o m
B a s a l t i ca n d e s i t e
l a v a s , up t o1 2 0
i n t h eB i gR o s aC a n y o n - M i l l i g a n
m t h i c ko v e r l i e
t h e sediments
G u l c h , b u tf a r t h e rn o r t h e a s tt h e y
d i r e c t l yo v e r l i et u f fo fT u r k e yS p r i n g s .T h e ya p p e a rt ob e
s e q u e n c eo f
a
a t l e a s t t h r e e f l o w s i n BigRosaCanyon.
l a v a i s b l o c k y ,b u t
P a r t of t h e
massive v e s i c u l a t e d material i s most common.
Elongated vesicles a r ec o n s i s t e n t l yo r i e n t e dn o r t h - s o u t h .
Near t h e c o n f l u e n c eo fM i l l i g a n
l a v a s are o v e r l a i nb yu pt o1 1 0
lithic-rich
y o u n g e rt h a n1 8 . 3
m o fb e d d e da n d
massive unwelded
T h e t u f f s a r e p r o b a b l yp r o d u c t s
a s h - f l o wt u f f s .
small e r u p t i o n sf r o mt h e
G u l c h andBigRosaCanyon,mafic
B.
0.
Ranch r h y o l i t el a v ad o m e ( s )w h i c h
Ma ( B o b r o wa n do t h e r s ,1 9 8 3 ) .
10
of
is
Quaternary
T h e T e n m i l e H i l l q u a d r a n g l e i s d o m i n a t e db yb r o a d ,c o a l e s ’ y e n t
t h e u p p e rs u r f a c e so fw h i c hh a v eu n d e r g o n e
a l l u v i a l - f a nd e p o s i t s ,
The alluvial-fan
v a r y i n gd e g r e e so fd i s s e c t i o na n de r o s i o n .
d e p o s i t sc o n s i s to fp a r t i a l l yi n d u r a t e ds a n d yc o n g l o m e r a t ea n d
is c o r r e l a t e d w i t h t h e P l i o - P l e i s t o c e n e
p e b b l ys a n d s t o n et h a t
-
P a l o m a sF o r m a t i o n
1986).
u p p e rS a n t a
Fe G r o u p( L o z i n s k ya n dH a w l e y ,
Up t o 40 m o f t h e s e s e d i m e n t s a r e e x p o s e di nM i l l i g a nG u l c h
t h e quadrangle
a l o n gt h ee a s te d g eo f
Most o f t h e
map a r e a i s c o v e r e db y
s u r f a c et h a ts l o p e sa b o u t
a c o n s t r u c t i o n a lg e o m o r p h i c
e a s t ( A similar w e s t - s l o p i n gs u r f a c e
1.5O
i s p r e s e n t i n t h en o r t h e a s tc o r n e ro f
1 to
t h e q u a d r a n g l e ) .W i t h i n
2 km of t h e San Mate0 f o o t h i l l s , t h e s l o p e o f t h i s s u r f a c e
i n c r e a s e s a b r u p t l yt oa b o u t
T h i ss t e e p e rs u r f a c ep r o j e c t s
3.0O.
w e s t w a r dt o w a r d st h eu p p e rr e a c h e so fR o s e d a l eC a n y o n ,N o r t h
C a n y o n ,a n dE x t e rC a n y o nw h e r es i m i l a rd e p o s i t so c c u r .P a r t i a l l y
a s i n s e tt e r r a c e sa l o n g
c o n s o l i d a t e dg r a v e l sa l s oo c c u r
o fE a s t
Red Canyon.
T h e h i g h e s to f
t h e sides
are
t h e a l l u v i a l - f a ns u r f a c e s
p r o b a b l ye q u i v a l e n ti na g et ot h eC u c h i l l os u r f a c e( L o z i n s k ya n d
H a w l e y 1, 9 8 6 b ) I. n c i s i o no f
C u c h i l l o ,r e p r e s e n t s
i n i t i a le n t r e n c h m e n to f
y e a r sa g o
t h i s s u r f a c e , i f e q u i v a l e n tt ot h e
a l o w e r i n g o f b a s el e v e l
i n r e s p o n s et o
t h e R i oG r a n d er i v e rs y s t e ma b o u t
400,000
( G i l e a n do t h e r s ,1 9 8 1 ) .
P a l o m a sF o r m a t i o nd e p o s i t s
h i g h - a n g l ef a u l t st h a te x t e n d
c e n t r a l p a r to f
are l o c a l l y o f f s e t b y
from s o u t h t o n o r t h a c r o s s t h e
T h e o f f s e t i s m o s ta p p a r e n ta l o n g
t h e quadrangle.
t h en o r t hs i d eo fN o r t h
a t l e a s t two
Canyon w h e r e t h eu p p e r m o s ts u r f a c e
o f f s e td o w n - t o - t h e - w e s ta b o u t
8 m.
11
T o p o g r a p h i cb r e a k si nt h e
is
alluvialsurface
a c r o s s b o t ho f
decrease g r a d u a l l y t o t h e n o r t h
t h e s ef a u l t s .S e d i m e n t sa l o n g
t h e s o u t h e r n wall o fN o r t hC a l y o n ,
u p s t r e a mo ft h ee a s t e r nf a u l t ,
i n c l u d e f a i r l yt h i c kd a r kc l a y s ,
a t y p i c a lo f
t h e P a l o m a sF o r m a t i o ni n
t h e map a r e a .
p r o b a b l yr e c o r da ne p i s o d eo ff a u l t i n gt h a t
The c l a y s
damnedNorthCanyon,
T h i s s t y l eo f
a n da l l o w e df i n e - g r a i n e ds e d i m e n t oa c c u m u l a t e .
to
s e d i m e n t a t i o n i s a l s on o t e di ns o u t h e r nM i l l i g a nG u l c ha d j a m n t
similar d o w n - t o - t h e - w e s tf a u l ts c a r p s( M a c h e t t e ,
1987).
of t h e
T h e r e i s no known b i o s t r a t i g r a p h i c c o n t r o l f o r t h e a g e
P a l o m a sF o r m a t i o ni n
t h e map a r e a .
There is a chance t h a t o.rganic
a s t h o s em e n t i o n e da b o v ec o u l db e
d e b r i s i nd a r kc l a y ss u c h
isotopically dated.
U n c o n s o l i d a t e dg r a v e l si nc a n y o nb o t t o m sa r e
a s a l l u v i u mt h a tr e p r e s e n t s
mapped s e p a r a t e l y
t h e most r e c e n t v a l l e y - f i l l e p i s o d e .
STRUCTURAL GEOLOGY
S t r u c t u r a l elements i n t h e
d i v i d e di n t o
T e n m i l e Hill q u a d r a n g l ec a nb e
two c a t e g o r i e s :s y n v o l c a n i cs t r u c t u r e s ,
a n d b a s i na n d
r a n g ee x t e n s i o n a ls t r u c t u r e sr e l a t e dt of o r m a t i o no ft h eR i oG r a n d e
Rift.
SYN-VOLCANIC
STRUCTURES
S t r u c t u r e sR e l a t e dt o
t h e V i c k sP e a kT u f f
i n the
T h e o l d e s tp o s s i b l es y n - v o l c a n i cs t r u c t u r ee x p r e s s e d
T e n m i l e Hill q u a d r a n g l e i s r e l a t e dt oe m p l a c e m e n to f
TuffF
. erguson
( 1 9 8 6 ) d e s c r i b e s a z o n eo fr o u g h l y
12
t h e V i c k sP e a k
E-W
trending
,
( 0 7 0 'a z i m u t h )
T u f f i n t h eE a s t
map a r e a .
s o u t h - s i d e - d o w nf o l d e da n dc o n t o r t e dv i c k sP s a k
Red Canyon area j u s t s o u t ho f
t h e SW c o r n e ro ft h e
m t o 2 1 5 m w i t h no
T h e V i c k sP e a kt h i c k e n s( f r o m1 2 0
1 km wide
e x p o s e db a s e )s o u t h w a r da c r o s st h ea p p r o x i m a t e l y
in
s t r u c t u r e .E l o n g a t ep r e f e r e n t i a l l yo r i e n t e dp u m i c ef r a g m e n t s
t h eV i c k sP e a kc o n s i s t e n t l yt r e n d i n ga b o u t
N20OW a r e p r e s e n t w i t h i n
t h i s S t r u c t u r e ,b u td on o to c c u rt ot h en o r t h .
a n ds o u t ho f
The
p a l e o m a g n e t i cp o l ep o s t i o no fs t e e p l yf o l d e dV i c k sP e a kT u f f
within
t h ef o l d e db e l t
i s similar t o i t s r e g i o n a l a v e r a g e p o l e p o s i t i o n
i n d i c a t i n gt h a t
i t c o o l e db e l o w
t h e C u r i et e m p e r a t u r ea f t e r
d e f o r m a t i o n( M c I n t o s h 1, 9 8 3 M
: c I n t o s h p, e r s o n a cl o m m u n i c a t i o n ) a, n d
t h a t a s o u t h - f a c i n gs c a r pe x i s t e d
h e r e d u r i n g t h e V i c k sP e a k
t h e e a s t a p r o b a b l yt i m e - e q u i v a l e n t
eruptionA
. l o n gs t r i k et o
s t r u c t u r e i s e x p o s e di nN o r t hC a n y o na l o n g
t h e s o u t h - c e n t r a le d g e
I n t h i s a r e a , a n o l d e r u n i t ( H e l l s Mesa T u f f )
of t h e q u a d r a n g l e .
i s b r e c c i a t e di n t ol a r g eb l o c k sa n dt i l t e dt ot h es o u t h
i na n
E-W
t r e n d i n gb e l t
a t l e a s t 0.5
20'
t o 70O
km w i d e .P a l e o m a g n e t i cp o l e
after cooling
p o s i t i o ns t u d i e si n d i c a t et h a tt h eb l o c k sr o t a t e d
b e l o w t h e C u r i e t e m p e r a t u r e( M c I n t o s h ,p e r s o n a lc o m m u n i c a t i o n ) .
T h i s i s n o ts u r p r i s i n g ,c o n s i d e r i n gt h eb r i t t l es t y l eo f
d e f o r m a t i o n here, and i t s p r o b a b l es y n - V i c k sP e a kT u f fa g e .
B r i t t l e s o u t h - s i d e - d o w nd e f o r m a t i o n
b e l ta l o n gs t r i k ef r o m
o f t h e H e l l s Mesa T u f f ,
fault
T u f f w a sd r a p e do v e ra na c t i v e
s c a r pr a t h e rt h a ne r o s i o n a ls c a r p( F e r g u s o n ,1 9 8 6 ) .T h i s
i m p o r t a n tb e c a u s e
to the
t h e f o l d e dV i c k sP e a k ,l e n d sc r e d e n c e
i n t e r p r e t a t i o n t h a t v i c k sP e a k
in a
is
a p a l e o v a l l e yf i l l e dw i t hV i c k sP e a kT u f fh a s
j u s t t o t h es o u t h( O s b r r n ,
b e e nr e c o g n i z e di nC o l dS p r i n gC a n y o n
1 9 8 2 ) .T h i sa d d i t i o n a ls t r u c t u r a le v i d e n c ec o m b i n e dw i t ht h e
a b r u p tt h i c k e n i n ga n dc h a n g e si nr h e o l o g yo f
13
t h e v i c k sP e a k
Tuff
s o u t ho f
i t i s a ni m p o r t a n tv o l c a ? o -
t h e s t r u c t u r es u g g e s tt h a t
t e c t o n i cz o n e
r e l a t e d t oe m p l a c e m e n to f
S t r u c t u r e of t h e M t .
t h e V i c k sP e a kT u f f .
W i t h i n g t o nC a u l d r o n
The s t r u c t u r a lm a r g i no f
the Mt.
mapped i n t h r e e areas ( F i g . 1 ) .
M o u n t a i n sn e a rM o n i c aS a d d l e ,
W i t h i n g t o nc a u l d r o nh a sb e e n
I n t h e n o r t h e r n San Mateo
t h e m a r g i n i s a n e a rv e r t i c a ls o u t h -
s i d e - d o w nf a u l tp l a c i n gc a u l d r o n - f a c i e sS o u t h
Canyon T u f fa g a i n s t
o u t f l o ws h e e t so fo l d e ru n i t s( O s b u r na n dF e r g u s o n ,
1986).
western MagdalenaMountains
In the
a w e s t - f a c i n gs t r u c t u r ep a r t i a l l y
o b s c u r e db yy o u n g e rr o c k s ,a l s oa p p e a r st ob ee s s e n t i a l l y
v e r t i c a lf a u l tb o u n d i n gt h i c kc a u l d r o n - f a c i e sS o u t h
a
Canyon t o t h e
northwest.
A t h i r de x p o s u r ee x t e n d sf r o m
t h eT e n m i l e
R i l l q u a d r a n g l et o w a r d st h ec e n t r a lS a nM a t e oM o u n t a i n s
T h i s marginsegment
saddle.
s l o p i n g (15'
t o 60')
i s n o t a v e r t i c a lf a u l t ,b u t
a gently
NW) m o n o c l i n a ls a gc o m p o s e do fn o r t h w e s t - t i l t e d
(20O
b l o c k so fp r e - c a u l d r o ns t r a t ar e p e a t e db yc l o s e l y - s p a c e d
s o u t h e a s td i p p i n gn o r m a lf a u l t s
C').
t h e s o u t h w e s tc o r n e ro f
( s e e west e n do fc r o s s - s e c t i o n
i s t h eb a s a l
The y o u n g e s tu n i to f f s e tb yt h e s ef a u l t s
unwelded member o f t h e S o u t h Canyon T u f f .
d r a p e do v e rt h ed e f o r m e db l o c k s ,a n d
C-
Welded S o u t h Canyon i s
i t s f l a t t e n e d pumice d e f i n e a
t i l t o f 1 5 0 east.
f o l i a t i o nc o n s i s t e n tw i t ht h er e g i o n a l
This
s t r u c t u r a ls t y l ec o n t i n u e sa l o n gt h em a r g i nt ot h es o u t h w e s tt o w a r d
C a v eP e a k s
w h e r e i t i s b u r i e db e n e a t ht h eu n i to fE a s t
To t h en o r t h e a s t ,t h em a r g i n
deposits.
Red Canyon.
is b u r i e db e n e a t hP a l o m a sF o r m a t i o n
T h e e x t e n s i o n of t h em a r g i na c r o s sM i l l i g a n
e s s e n t i a l l y a s t r a i g h tl i n eb e t w e e n
t h e c e n t r a l SanMateoand
w e s t e r nM a g d a l e n as e g m e n t s .I nt h ee a s t e r np a r to f
14
Gulch is
t h e quadrangle,
cross-section
( P l a t e 2 ) shows t h e c a u l d r o nm a r g i n
B-B'
s t r u c t u r a l s t y l e similar t o t h a t
a s a g g e dm a r g i nh e r e
e v i d e n c eo f
west.
known t ot h e
The only
is two small h i l l s o fn o r t h v e s t t h e S o u t h CanyonTuff
t i l t e dw e l d e dt u f f rp r o b a b l y
with a
ortuffof
T u r k e yS p r i n g s( m a p p e da sT u r k e yS p r i n g so nP l a t e
1).
j u s t n o r t h w e s to fv i r t u a l l yf l a t - l y i n ge x p o s u r e s
These occur
of L e m i t a rT u f f .
B A S I N AND RANGE F A U L T I N G
The Least P r i n c i p a l S t r e s s D i r e c t i o n
B a s i na n dR a n g ee x t e n s i o nr e l a t e dt of o r m a t i o no f
Rift
area.
( C h a p i n r1 9 7 9 )h a sa f f e c t e d
a l l T e r i a r y s t r a t a i nt h e
t h e O l i g o c e n ew a so r i e n t e da b o u t
c o n s t r a i n e db e t w e e n
27.97
N ~ ~ O E .T
h i s d i r e c t i o n i s from t h e
111).
Two of t h e s e d i k e ' sa g e s
t h e v i c k sp e a ka n d
a P l i o c e n ed i r e c t i o no f
o t h e r s( 1 9 8 1 r
p.
423).
s t r u c t u r a lm a r g i no ft h e
t r e n d i n g N55'E.
M
a and
stress d i r e c t i o n is
N70°E r e p o r t e db yZ o b a c ka n d
I n t r u d i n gt h eS o u t h
Mt.
are c l o s e l y
Lemitar T u f f s , 28.46
Ma ( M c I n t o s ha n do t h e r s 1
, 986)T
. his
similarto
t h e map area
j u s t s o u t h w e s to f
t r e n d so ff o u rr h y o l i t ed i k e s
p.
map
stress d i r e c t i o nf o rt h i sa r e ad u r i n g
T h e l e a s tp r i n c i p a l
(FergUSOnr1986r
t h e R i oG r a n d e
Canyon a l o n g t h e
W i t h i n g t o nc a u l d r o n
T h i s t r e n d i s i n t e r p r e t e da s
p r i n c i p a l stress c r e a t e d b y t e n s i o n o r t h o g o n a l t o
m a r g i n of t h e c a u l d r o n .
15
i s a r h y o l i t ed i k e
a localized least
t h e downwarped
F a u l tP a t t e r n s
map a r e a a r e g e n e r a l l y p a r a l l e l t o
Normal f a u l t s i n m o s t o f t h e
each o t h e ra n d
t r e n d a b o u t N300W.
An e x c e p t i o n i s i n t h e s o . l t h w e s t
c o r n e r of t h eq u a d r a n g l et ot h es o u t ho ft h e
Mt.
Withington
Two s e t s of o fn o r t h - s o u t h( w e s t - s i d e - d o w n )a n d
c a u l d r o nm a r g i n .
here.
e a s t - w e s (t s o u t h - s i d e - d o w n t) r e n d i n gf a u l t so c c u r
i n t h e E a s t Red Canyon a r d a
o r t h o g o n a ls t r a i np a t t e r np r e v a i l s
i s t h o u g h tt o
( F e r g u s o n l1 9 8 6 ) 1a n d
b a s e m e n ts t r u c t u r e s
F a r t h e rn o r t h lw i t h i nt h e
o r i e n t e dp e r p e n d i c u l a r
r e f l e c t t h ei n f l u e n c eo fo l d e r
N ~ ~ Ol eEa s t
on t h e
Mt.
This
p r i n c i p a l stress d i r e c t i o n .
W i t h i n g t o nc a u l d r o n !f a u l t s
are
t o t h e stress d i r e c t i o n p o s s i b l y b e c a u s e
e f f e c t so fb a s e m e n ts t r u c t u r e s
the
were n e g a t e db yt h ep r e s e n c eo f
a
y o u n gi s o t r o p i cs u b - c a l d e r ap l u t o n .T h er e s u l t a n tv e c t o ro f
to the
f a u l t p a t t e r n s is g e n e r a l l yp a r a l l e l
e x t e n s i o nf o rb o t h
l e a s t p r i n c i p a l stress d i r e c t i o n( F e r g u s o n ,1 9 8 6 ) .
M a g n i t u d e a n d D u r a t i o no fE x t e n s i o n .
B a s i na n dr a n g ef a u l tb l o c k s
t h e map a r e a .
15'
t o 40-50'
margin.
a r e t i l t e d t o t h e e a s tt h r o u g h o u t
T h e d e g r e e of t i l t i n c r e a s e s d r a m a t i c a l l yf r o m
n o r t h w a r da c r o s st h e
Mt.
10-
W i t h i n g t o nc a u l d r o n
T h i s c o r r e s p o n d s t o a ni n c r e a s ei nt h ea m o u n to fe x t e n s i o n
t o a s much a s 100%.
fromabout20%
CanyonTuff
T h i s p l a c e si n t r a c a u l d r o nS o u t h
w i t h i n t h em o d e r a t e l ye x t e n d e dd o m a i no fC h a m b e r l i na n d
Osburn ( 1 9 8 4 ) .
Y o u n g e r o c k s !i n c l u d i n g
S p r i n g s lt h a to v e r l i e
s u g g e s t i n gt h a t
t h e t u f fo fT u r k e y
t h e S o u t h Canyon a r e t i l t e d o n l y
t h e i n t e r i o r of t h e M t .
e x t e n d e d as much a s 80% between27.4
16
5-15O
W i t h i n g t o nc a u l d r o nw a s
Ma ( a g e o f t h eS o u t hC a n y o n )
~
a n db e f o r ee m p l a c e m e n to ft h et u f fo fT u r k e yS p r i n g sj u s tb e f o r e
24 Ma ( M c i n t o s ha n do t h e r s r
t h e e n do ft h eM i o c e n ea b o u t
Deal ( 1 9 7 3 ) i n t e r p r e t e d t h i s a n g u l a ru n c o n f o r m i t y
19815).
a s evidencm? f o r
r e s u r g e n c e of t h e Plt. W i t h i n g t o nc a u l d r o n ra n ds u g g e s t e dt h eh i g h
a s b e i n g a r e m n a n to f
a r e a so ft h en o r t h e r nS a nM a t e 0M o u n t a i n s
t h i s uplift.
T h e l a c ko fr e l i a b l em a r k e rh o r i z o n si n
makes i t d i f f i c u l t t o d e s r i b e
t h e S o u t h CanyonTuff
how l a r g ea m o u n t so fe x t e n s i o n
a r e n e e d e dt or e p e a t
achievedN
. u m e r o u sn o r m a lf a u l t s
was
t h e steeply-
d i p p i n gs t r a t ai nt h en o r t h w e s tc o r n e ro ft h eq u a d r a n g l e ,b u tt h e r e
t h e s e f a u l t s .C r o s s - s e c t i o n
i s no i n d i c a t i o no ft h ed i po f
A-A'
s h o w sn u m e r o u sm o d e r a t e l y - d i p p i n gf a u l t st oa c c o u n tf o rt h el a r g e
d e g r e eo fe x t e n s i o n
t h a t o c c u r r e dp r i o rt od e p o s i t i o no fy o u n g e r
t h e u n i t o f E a s t Red
u n i t s .Y o u n g e rh i g h - a n g l ef a u l t s ,t h a to f f s e t
Canyon, a r e shown a s s t e e p e r f a u l t s c u t t i n g
of t h e s e f a u l t s
( e a s t e d g eo f
t h e o l d e fr a u l t s .
One
sec. 2 4 , T5Sr R5W) o f f s e t s a
p e d i m e n t e db e d r o c ks u r f a c ei n d i c a t i n gt h a t
i t i s f a i r l y youngand
p r o b a b l yh i g h - a n g l e .
L a r g ed e g r e e so fe x t e n s i o n
the Mt.
may a c c o u n tf o r
W i t h i n g t o nc a u l d r o no r i e n t e dp a r a l l e lt o
p r i n c i p a l stress d i r e c t i o n .
SouthCanyonTuff
i n d i c a t i n gt h a t
N o r t ha n d
the least
However,
flow-banded
pumice
in the
a r e o r i e n t e dp a r a l l e lt ot h ec a u l d r o n ' sl o n ga x i s
i t may haveformed
west o f t h e
r u g g e d area ( M t .
t h e o b l o n gs h a p eo f
a s a ne l o n g a t ed e p r e s s i o n .
Tenmile H i l l quadrangle l i e s an extremely
W i t h i n g t o nW i l d e r n e s s )
c a u l d r o n - f a c i e sS o u t h
Canyon T u f f .
u n d e r l a i n b yt h i c k
The s t r u c t u r a lg e o l o g yo f
this,
e s s e n t i a l l y unmapped a r e a , i s p o o r l yu n d e r s t o o d F
. u r t h e rm a p p i n g
i n t h i s a r e a may h e l pa n s w e ra t
t h ei n t e r i o ro ft h ec a u l d r o n .
l e a s t two c r i t i c a l q u e s t i o n sa b o u t
Are l a r g e a m o u n t so ft i l t i n gd u e
17
to
a c o m b i n a t i o no f
c a u l d r o nr e s u r g e n c e ,o rr e g i o n a le x t e n s i o n ,o r
these?
What is t h en a t u r eo f
t h e t r a n s i t i o nf r o mm o d e r a t e l y
e x t e n d e dt ow e a k l ye x t e n d e dS o u t h
I n the
t o t h e west.
CanyonTuff
7 . 5 ' q u a d r a n g l e ,t h i sc h a n g eo c c u r sa b r u p t l ya c r o s s
G r a s s yL o o k o u t
a n o r t h - t r e n d i n ge a s t - s i d e - d o w nf a u l t .
T h i s f a u l tr u n sj u s te a s t
Mate0 M o u n t a i n sj u x t a p ( 7 s i n g
o ft h eh i g hc r e s to ft h en o r t h e r nS a n
" b o t t o m l e s s "s t e e p l y - t i l t e dS o u t h
Canyon t o t h e
east a g a i n s t
west
g e n t l y - d i p p i n gS o u t hC a n y o no v e r l y i n gL e m i t a rT u f ft ot h e
( F e r g u s o n 1, 9 8 6 ) .
Neotectonics
Two n o r t h - s o u t h t r e n d i n g f a u l t s t h a t e x t e n d a c r o s s t h e c e n t r a l
p a r to f
t h e s t u d y a r e a o f f s e tP l i o - P l e i s t o c e n eP a l o m a sF o r m a t i o n
deposits.
a n dp r o b a b l y
T h e s c a r p sa s s o c i a t e dw i t h
t h e s e f a u l t sa r ev e r ys u b d u e d
were l a s t a c t i v e 100,000 t o 200,000 y e a r sa g o
( M a c h e t t e 1, 9 8 7 ;
p.
15).
The e a s t e r nf a u l to c c u r s
s e r i e s o fs m a l lb e d r o c ki n s e l b e r g st h a te x t e n da c r o s s
quadrangle.
A t t h e s o u t h e r ne d g eo f
j u s t west o f a
the
t h e q u a d r a n g l et h i s
fault
accommodates a t l e a s t 600 m o fw e s t - s i d e - d o w nd i s p l a c e m e n ti n
O l i g o c e n eu n i t s .
I t i s p o s s i b l et h a tP a l o m a sF o r m a t i o nd e p o s i t s
west o f t h e f a u l t ,e v e nt h o u g h
a r e v e r yt h i c kt ot h e
amount i s shownon
cross-section
a minimum
C-C'.
ECONOMIC GEOLOGY
Practicallynothing
i s known a b o u tp r e - T e r t i a r yg e o l o g y
of t h e
T e n m i l e H i l l q u a d r a n g l e .T e r t i a r yD a t i l - G r o u pr o c k st ot h es o u t h
o v e r l i e a t h i ns e q u e n c eo fu p p e rP a l e o z o i c
18
s t r a t a a b o v eP r e c a m b r i a n
c r y s t a l l i n eb a s e m e n (t A t w o o d 1, 9 8 2 ) .
p o t e n t i a lo f
T h e p e t r o l e u mr e s o u r c e
t h e a r e a i s t h e r e f o r ev e r yl o w ,e v e nt h o u g h
F o s t e r( 1 9 8 8 )s u g g e s t
G r a y t and
t h e p o s s i b i l i t yo fg r e a tt h i c k n e s s e so f
C r e t a c e o u s s t r a t a here.
T h e R o s e d a l ee p i t h e r m a lg o l d
d i s t r i c t , h o s t e db yi n t r a c a u l d r o n
km west o f t h e q u a d r a n g l e
S o u t h CanyonTuff!
is l o c a t e d 3-4
( F e r g u s o n ,1 9 8 6 ) .
The d i s t r i c t is s u r r o u n d e d. b y
a r g i l l i c a l l y a l t e r e d r o c kw h i c h
a n ds o u t ho f
extends a l o n gf a u l t st o
t h e north
was n o to b s e r v e di n
t h e m i n e .T h i sk i n do fa l t e r a t i o n
t h e map a r e a .
P a l o m a sF o r m a t i o ns e d i m e n t sa l o n gt h e
t h eq u a d r a n g l e
were d e r i v e df o r me r o s i o no f
c o n t a i ne c o n o m i c
a h a l oo f
west e d g eo f
t h e s e r o c k s !a n d
may
placer d e p o s i t s .
A n o t h e rp o s s i b l ee c o n o m i cr e s o u r c e
of t h ea r e a
is z e o l i t e
m i n e r a l i z a t i o n t h a t e f f e c t s p u m i c ef r a g m e n t si nu n w e l d e da s h - f l o w
t u f f so ft h eP o p o t o s aF o r m a t i o n
i n BigRosaCanyon.
The c o n t a c t
b e t w e e n b a s a l t i c a n d e s i t e l a v a sa n dP o p o t o s as e d i m e n t si nt h i sa r e a
i s o f t e na l t e r e da n di n v a d e db yc a l c i t ev e i n s ,a n d
v e s i c l e sc o n t a i nm i n e r a l s( u n i d e n t i f i e db y
b e of i n t e r e s t t o c o l l e c t o r s .
19
some o ft h e
t h e a u t h o r ) t h a t could
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M.S. t h e s i s , U n i v e r s i t yo f
New
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G. R.,
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, iocene
N e w Mexicol &
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p. 205-210.
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i n t h e S o c o r r o a r e a o f t h e Rio G r a n d e
R i f t , c e n t r a l N e w M e x i c o( a b s . ) :G e o l o g i c a lS o c i e t yo f
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,.
16, n o .6 ,
p. 467.
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Rift--a summary,
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p. 1-5.
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of
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t u f f s : Ph.D. d i s s e r t a t i o n ,
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of t h e SanMateo
N e w Mexico--a s t u d y o f a r h y o l i t e
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Deal, E. G . , andRhodesl
R. C . , 1 9 7 6 ,V o l c a n o - t e c t o n i cs t r u c t u r e s
i n t h e San M a t e oM o u n t a i n s ,S o c o r r oC o u n t y ,
New Mexico, i n
E l s t o n , W. E . , a n dN o r t h r o p ,
S. A. ( e d s . ) ,C e n o z o i cv o l c s i s m
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P u b l i c a t i o n5 ,
p. 51-56.
in
t h e Squaw P e a ka r e a ,M a g d a l e n a
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I n s t i t u t eo fM i n i n g
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21
G e o l o g iccr o s s - s e c t i o n s
of
t hTee n m i l e
Hill
Plate
New M e x i c o
7 . 5 ' q u a d r a n g l eS,o c o r rCoo u n t y ,
2
N M B M 8 rO
MpRe n - FMi laep
283
All subsurface contacts and faultsareinterpretive.
Solid linesindicate
thereissurface
evidencefor theauthor'sinterpretation.
Bashed lines
indicatethatthere
is no surface evidencefor theinterpretation.
Crosssection A-A' uses surface information from mapping tothe north (Donze,
1980, NMBMScNlR Open-file Report 123) as well as information from this
quadrangle.
;.
I
,
I
I
c
4
0
fiQ
A
u
8,0007
b
0
4-
o
Contact.
A'
al
v)
.-c
F8,OO0
Fault, arrow showing moveyent of downthrownblock.
-
I
yy
Fault intersectedat a low angle by the plane of the cross-section.
o denotes arrow coming out of cross-section plane,
i denotesinto cross-section plane.
0;
Contortedfoliation
or sedimentary bedding.
Apparent dip of e.ut6.iiti.c foliaticn
In the .South .cabyon. Tuff.
1.
-a
I
a
c
c
0
.-+
B
8,000
0
.+
0
B'
0
al
Q)
v)
I
v)
v)
.-c
8,000
-0
7,000
Q)
m
7,000
9,
cr,
\
.--"
7
Qtg
Qtg
Q tg
?
"TI
I
I
I
"
"
"
"
"--TVP - - -
7
-
""
"
"
Thm
1-
c
0
.-
e
C
8,0007
D
c
Q)
m
4
0
2
Q
u
C'
-7,000
..*-A
.
4,000