GEOLOGYANDCOALRESOURCES
SHOEMAKER CANYON SE QUADRANGLE, CIBOLACOUNTY,
NEW MEXICOBUREAUOF
NEW MEXICO
MINES AND MINERALRESOURCES
O P E N - F I L ER E P O R T
172
bY
O R I N J. ANDERSON
N e w Mexico B u r e a u of Mines and Mineral R e s o u r c e s
and
U.
WILLIAM J. MAP,EL
S. G e o l o g i c a l Survey
May 1 9 8 3
Contents:
(1) D i s c u s s i o n of G e o l o g y and C o a Rl e s o u r c e s
(2)
1:24,000
G e o l o g i c Map ( a c c o m p a n y i n g )
Contents
GEOLOGY
General
P.
1
Study Area
Structure
Stratigraphy
P.
P.
5
5
P.
6
Coal Resources
p. 24
ACKNOWLEDGMENTS
p. 25
REFERENCES
p. 28
Figures
Fig. 1.
Fig.
2.
Fig.
3.
Index mapof Zuni Basin showing
study area
Stratigraphic section, sec. 12,
T. 7 N., R. 17 W.
Stratigraphic section, sec. 34,
T.
Fig.
4.
7 N.,
R. 16 W.
5.
Stratigraphic section, sec. 30,
I N., R. 16 W.
Stratigraphic section, sec. 20,
T. I N., R. 16 W.
Stratigraphic section, sec. 24,
T. 7 N., R. 11 W.
T.
Fig.
Fig.
2
p. 12
p. 14
Stratigraphic section, sec. 3 ,
T. 6 N., R. 16 W.
Fig.
P.
6.
7.
p. 15
p. 16
p. 11
p. 19
Tables
Table 1. Analysis of coal from Gallup
Sandstone, sec. 33,T. 8 N., R.
Table 2.
Table 3.
16 W.
p. 26
Coal Resources Estimates in Gallup
Sandstone, Shoemaker Canyon
SE
Quadrangle
Land and Mineral Ownership
p. 21
p. 30
GEOLOGY
General
The Shoemaker CanyonSE quadrangle lies in the southern part
of the Zuni Basin,
a broad, shallow structure that extends
southwestward
from
the
Zuni
Mountains
of New
Mexico
into
east-
central Arizona. As such, the quadrangle lies near the southeast
margin of the Colorado Plateau. The regional dip in the study
area
is
very
gently,
but
perceptibly,
northeastward
toward
the
axis of the GalLup sag which comprises the northeast and deepest
part of the Zuni Basin. The northeastward dips are interrupted
locally by broad,
low amplitude, NW-SE-trending folds, by minor
up on the
faulting, and byW-SE trending monoclinal flexures
northeast side. At least two monoclines with sinuous, generally
northwest-trending axes have been identified
in the general area,
Anderson,
the largest of which is the Atarque monocline1;(Fig.
1982a).
upper
The area under consideration is underlain(1)by
Cretaceous sandstones and shales that exceed
900 ft in thickness
(2)
where the Torrivio Member
of the Gallup Sandstone is present
nearly 100 ft of Jurassic eolian sandstone, and
(3) 800 to 1000
ft of the Triassic Chinle Formation with
30 ato 40 ft thick
section
of
the
Rock Point
Memberof
the
Wingate
Sandstone
capping
it. No Jurassic or Triassic rocks are exposed
on the Shoemaker
Canyon SE quadrangle, but good exposures are present a short
distance to the west
on the
(Anderson, 1Y82b)
.
adjacent
Mesita
de Yeso
quadrangle
-~
S-~
arlnoerville
-
. ..
i
"
~
h.) Index
mop of theZuniEosinshowingthestudyareainrelationtoother
quadrangles discussed in text, monoclind structures. southwesternmost
i c c u r e n i e o f theFiteRonch'MemberoftheTresiiermanosFormation,
and the North Plainsiavofield.
,
~-'
1
The Paleozoic section in the subsurface may be inferred
12 miles to the northwest (holeinis
from an oil test drilled
the NE 1/4 sec. 5, T.YN., R.18W., drilled in 1Y63 by Cities
Service Oil Co.;(C. H. Maxwell and L. G. Nonini, written commun.,
1977).
This test showed a1,400 ft section of Paleozoic rocks
capped by the San Andres Limestone. Assuming locally uniform
thicknesses a total sedimentary section
of approximately 3,400
ft overlying
the
Precambrian
basement
may
be
present
in
the
study area.
The main body
of the Dakota Sandstone, which crops out
within 0.7 miles
of
the
western
boundary
of the Shoemaker Canyon
SE quadrangle makes up the lowest part
of the Cretaceous section
(Hook, Cobban, and Landis, 1980).
in west-central New Mexico
This unit consistsof approximately 100 ft of nonmarine, marginal
marine, and marine sandstones and shales that were deposited
in
front
of
and
immediately
behind
the
shoreline
of
the
advancing
interior seaway during Cenomanian time. The lower two-thirds
to three-fourthsof the formation is nonmarine, with fluvialchannel sandstones at the base overlain by paludal shales. The
shales
are
locally
carbonaceous
with
very
minor
coaly
beds.
The very thin, lenticular coaly beds are of very poor quality
and represent sedimentation in a transgressive sequence.
Following the Dakota-Mancos transgression, the regressive
Atarque
Sandstone-Moreno
Hill
sequence
and
the
partly
equivalent
Tres Hermanos Formation (Hook, Molenaar, and Cobban, 1Y83)
were
deposited
, A subsequent
throughout
marine
much
of west-central
transgression,
New
represented
Mexico.
by
the
upper
member
4
of the Tres Hermanos Formation (the Fite Ranch Member) and
the overlying Pescado Tongue of the Mancos
Shale, set the stage
for a major regressive episode during which the Gallup Sandstone
was deposited.
Basaltic lavas and associated extrusive rocks erupted in
Quaternary time in the large North Plains field,
lava
which
lies mostly along the east side of the Zuni Basin east and
1).
northeast of the study area (fig.
of
lava
extends
from
the
A long, narrow tongue
the
main ofbody
lava
field,
crosses
the southern part of the Shoemaker
SE and nor.thern part of the
Dyke quadrangles, and extends from there westward across the
central part of the Zuni Basin for more 25than
miles into
Arizona. This tongue of lava follows the course of Jaralosa
of its Length, and is referred.to here as the
Draw for much
Jaralosa Draw Lobeo f the North Plains lava field (fig.
1).
The basalt has been dated 1.41
at m.y. by Laughlin, Brookins,
Damon, and Shafiqullah (1979).
Coal of good quality occurs in the middle
part, or Carthage
Member, o f the Tres Hermanos Formation, and in the middle part
o f the Gallup Sandstone. Coal beds
in these units, and in the
partly equivalent Moreno Hill Formation which crops out to the
south and west, are commonly1 to about 3 feet thick, but
locally are thicker (Campbell,1981).
The base of the Carthage
Member of the Tres Hermanos Formation defines the southern and
southwest edge of the Gallup-Zuni coal field. The Jaralosa
Draw
Lobeo f the North Plains lava field immediately to the
south intervenes to separate this coal field from the Salt Lake
5
field farther to the south and west. Coal resources in the
Shoemaker CanyonSE quadrangle lie within the Gallup-Zuni coal
field and are discussed in greater detail
in the last section
of this report.
Study
Area
Structure
The monoclines described earlier
do not extend into this
quadrangle so the structure is simple. Gentle northeasterly
dips that define the southwest flank of the Gallup Sag persist
..
across the Shoemaker CanyonSE quadrangle. There is, however,
a slight tendency for the dips to become more directly east
in the southeastern portion of the quadrangle, but they remain
at between '1 and .'2
Dips become slightly south of east
in
the southwest corner of the quadrangle. The top of the Atarque
Sandstone Member (the basal member of the Tres Hermanos Formation)
is at approximately 7,200 ft in sec.3 , T6N., R.l?W., whereas
3 miles to the south in sec.
22, on the Dyke quadrangle
(Campbell, 1982) it is below
6,960. A minimum dropof 250 ft.over
0
this distance indicates an average southward dip of 1..
about
It is, however, quite likely that the dip is locally somewhat
greater thanlo along a shortE-W trending segment of a gentle
monoclinal flexure down to the south, that is concealed by the
Jaralosa Draw Lobe of the (fig.1) basalt flow. The more
prominent monoclines in the region have sinuous axial trends
and probably the axial trends of less prominent monoclines
are also sinuous.
b
Faulting is minimalon the quadrangle. The only fault
mapped is
a
high-angle
normal
fault
trending
just
west
of
north
near the quadrangle boundary in sec.
22, T7N., R.17W. The
displacement is about15 ft, upthrown on the east or northeast
as are other minor faults in the region.
Stratigraphy
of the Dakota Sandstone crops out several
The Paguate Tongue
SE quadrangle (near
hundred feet west of the Shoemaker Canyon
East Joe Windmill
in sec. 1 6 , T7N., R.17W., on the Mesita de
Yeso quadrangle (Anderson,1982b). The oldest rocks exposed
on the quadrangle are those of the Whitewater Arroyo Tongue of
the Mancos Shale (Cretaceous) which overlies the Paguate Tongue
of the Dakota Sandstone. Cretaceous rocks exposed on the
quadrangle, in ascending order, are divided into the Whitewater
Arroyo Tongue of the Mancos Shale, the Twowells Tongue of the
Dakota Sandstone, the Rio Salado Tongue of the Mancos Shale,
the Atarque Sandstone, Carthage, and Fite Ranch Members of the
Tres Hermanos Formation, the Pescado Tongue
of’the Mancos Shale,
the F Member of the Gallup Sandstone, a middle, coal-bearing
part, and the Torrivio Member of the Gallup Sandstone.
These are the only rocks exposed in the quadrangle other than
the Quaternary basalt flows along the southern edge.
The
Whitewater
Arroyo
Tongue
of
the
Mancos
Shale
overlies
the Paguate Tongue throughout the Zuni Basin. The name was
proposed by Owen(1966) who applied it to a “well defined,
persistent tongue of marine shale separating the Twowells Tongue
from
the
rest
of
the
Dakota
Sandstone
in
the
southwestern
part
7
of the San Juan Basin" (and
in the Gallup sag
area).
A type
section was designated
in Whitewater Arroyo in sec. of
17
T.12N., R.l9W., near the village Two
of Wells, where'.tt is80
ft thick and described as a gray to olive-gray, silty, oysterbearing shale. It crops out only sparingly in the present
study area where it consists
of an estimated 60 ft of medium- to
dark-gray fissile shale and contains the relatively large oyster
Exogyra trigeri (Coquand) inits middle portion. A l s o very near
the
middleis a
distinctive
white-
to
orange-weathering
15-inch-
thick bentonitebed, but the bentonite is not well exposed
in
the quadrangle. The best exposures
of the Whitewater Arroyo
Tongue, albeit only the upper
half, may be found in the 1N1 2
sec. 10, T.7N., R.l7W., where the easily eroded shales are
the
protected by a cover of sandstone of the Twowells of
Tongue
Dakota
Sandstone.
o f the Dakota Sandstone crops out in
The Twowells Tongue
the
northwestern
part
of the
quadrangle
where
the
tongue
may
reach 20 ft in thickness but is generally less. The Twowells
very fine grained,
locally consists of1) a basal, 4-ft-thick,
flat-
to
wavy-bedded
sandstone
that
is locally
burrowed
and
very fossiliferous at the
top; this basal portion with a thin,
is well exposed alongN " 3 2 in secs.
bentonitic clay overlying
6 and 7, T.6N., R.l7W.,o f the adjacent Mesita de Yeso quadrangle,
2)
an overlying gray, shaly sandstone of variable thickness,
generally poorly exposed, that is also locally fossiliferous;
and 3 ) an upper, fine-to lower-medium-grained, pale-yellowish-gray,
crossbedded sandstone, characteristically with thinly interbedded
shale, and clay clasts; wavy bedding is also a characteristic
of
8
this upper sandstone. The Twowells may be seen, though poorly,
at the quadrangle.boundary in the
SW 114 sec. 3 4 , T.8N., R.l7W.,
and in sec. 10 one mile to the south.
Fossils in the Twowells consist almost exclusively of
Pycnodonte kellumi, fragments of Exogyra trigeri (Coquand), and
small specimens of Exogyra levis. Evidence of burrowing and
bioturbation is common throughout; the burrows include
Ophiomorpha. Both the Twowells and the Paguate Tongues may
represent
minor
regressive
pulses
in the
Dakota-Mancos
transgressive sequence. The Twowells in particular contains
features, such as opposed cross-bedding, that suggest deposition
in a tidal channel environment.
The Rio Salado Tongue of the Mancos Shale represents a
rapid return to open-marine, deeper water conditions or an
interruption
in
the
sand
supply
following
deposition
of
the
Twowells
The Rio Salado consists of
up to 240 ft of medium-gray and
grayish-brown shale, calcareousshale, and thin calcarenites
with a sequence of interbedded shale and very fine grained
sandstone at the top where the tongue grades into the overlying
Tres Hermanos Formation.
The
name
Rio
and Cobban (1983).
Salado
Tongue
was
proposed
Hook,
byMolenaar,
It is defined as the shale tongue lying
between the Twowells Tongue of the Dakota Sandstone and the
Atarque Sandstone Member
of the Tres Hermanos Formation (Atarque
Sandstone to the southwest) and is coextensive with these two
units.
Thin calcarenite and calcareous shale beds occur
30-40 ft
9
above the base of the Rio Salado and represent the Bridge
Creek Limestone Member
of the Greenhorn Formation (Hook, Cobban,
and Landis,1980).
at
a
The Bridge Creek Beds may often
by recognized
distance
in outcrop
because
the
yellow-weathering
calcarenites
stand out in contrast to the typically gray Mancos Shale. The
Beds are well exposed locally
on the adjacent Mesita de Yeso
thin calacrenites contain abundant fragments
quadrangle, where the
of Pycnodonte newberryi (Stanton). These Beds were deposited
during the very late Cenomanian (Greenhorn) transgressive
maximum,
a
time
that
was
of limestone
marked
by the deposition
beds throughout most of the Western Interior seaway. The Beds
€orm important marker horizons for regional correlation. The
guide fossil Pycnodonte newberryi (Stanton) appears
in abundance
at or just below this interval (Hook and Cobban, 1977).
-P. newberryi
on
the
were
adjacent
as weathered
collected
in the NE 114 sec. 1, T . 6 N . , R.l8W.,
Mesita
de
Yeso
quadrangle;
Creek
were
also
specimens in float
in the extreme northwest corner
of the Shoemaker Canyon
SE quadrangle.
Bridge
they
Beds
may
be recognized
In the subsurface the
by
a
distinctive
resistivity
kick they produce on the electric log, which is helpful in
correlations.
Beds, limestone
About 100 ft above the Bridge Creek
concretions commonly appear
in the section, but are found only
SE quadrangle. Associated
sparingly in the Shoemaker Canyon
with
the
concretions
in the vicinity are the ammonites Mammites
-
depressus, M. nodosoides,
Proplacenticeras
Neoptychites cephalotus (Anderson, 1982).
cununinsi,
and
Also, found locally
found
in association with the concretions are Ostrea
sp., Veniella
mortoni, Baculitessp., Turritella sp. and other gastropods,
but none
of these were collected
on the Shoemaker CanyonSE
quadrangle. This part of the Rio Salado is best exposed in the
14, 22, 23, 27,
west-central portion of the quadrangle in secs.
and 34 of T.7N., R.17W.
The Atarque Sandstone Member of the Tres Hermanos Formation
is
the
term
proposed Hook,
by Molenaar , and
Cobban(1Y 83) f o r
the regressive coastal-barrier sandstone unit that overlies
the Rio Salado Tongue of the Mancos
Shale and as such marks the
first major regression of the seaway following the Dakota-Mancos
(Greenhorn) transgression. The Atarque Member and the overlying
nonmarine Carthage Member are equivalent to the Atarque Sandstone
and the Moreno Hill Formation respectively (Hook, Molenaar,
and Cobban, 1983; and McLellan and others, 1983); the last two
stratigraphic
names
are
used
to
the
south
and
west
SE quadrangle where the Pescado Tongue and
of the Shoemaker
the Fite Ranch Member are not present (Anderson, 1982a).
As the Late Cretaceous shoreline had assumed a general
NW-SE trend in this area, the Atarque prograded northeastward
into the Mancos seaway and thus it is a diachronous unit that
becomes younger to the northeast. Throughout much
of,the Zuni
Basin, it is a cliff-forming unit and consists 1)ofa lower
flat-bedded
sandstone
which
appears
in most outcrops as the
first massive unit overlying the transitional zone at the top
of the underlying Mancos Shale. This unit coarsens upward
from very fine to fine grained;
2) a medial, fine-grained,
11
shaly unit of varying thickness,
but generally 5-15 ft; and
3) an overlying, lower- to upper-fine-grained, mostly crossbedded
sandstone, fossiliferous at the
top, that is 14-20 ft thick.
Units 1) and 3 ) are similar to the lower and upper shoreface
sandstones or Molenaar (1973).
The lower shoreface unit is
thought to have been deposited offshore beyond the zone where
wave action o r longshore currents influenced sedimentation.
Deposition
of
the
upper
shoreface
unit
probably
took
place
in
the zone where longshore currents were active. Burrows, including
Ophiomorpha, are common in the lower flat-bedded unit and less
common above.
In addition to these three
units, onthis quadrangle and
east of it, an upper unit composed of white to very pale orange,
upper-fine-grained, crossbedded sandstone forms a small but
consp5cuous cliff that rises above
a small bench developed on
Twelve miles to the west
the upper shoreface unit (Fig.
2).
of the quadrangle, this uppermost sandstone is present as a
nonmarine unit, a fluvialo r distributary channel sandstone
(Anderson, 1982a), and was included with the overlying Moreno
Hill Formation. On the present quadrangle, this white upper
sandstone is more marine in nature (no clay clasts, no ripple
marks, etc.) and is a relatively widespread, uniform deposit.
The top is commonly burrowed and root penetrated and is overlain
by a paludal shale (see again
Fig. 2).
sequence
here
could
indicate
a
The thicker Atarque
shoreline
stand
between
and the Atarque Sandstone outcrops mi12to the west, with a
resultant build-up of the upper shoreface unit.
here
12
Shoemaker CanyonSE stratigraphic section, upper part
of The Rio Salado Tongueof MancOS Shale, and lower
part of Tres Hermanos Formation SEk
in NEk Sec. 12,
T. IN., R. 17W.
Fig. 2
I
I
Carthage
Member
T
4
Scale
(ft)
ss; burrowed,bioturb.,
Paludal sh, with carbonaceous zone in lower half
ss;
Very pale orange to very light gray lower
gr. fn.
thin to medium sets of festoonlowtvpe
to moderate
angle cross beds; burrow casts sparse; top root
penetrated
j
m
e
n
t
e
d
Lower to upper fn. gr. cross bedded
ss; upper
"
Atarque
Member
ightgray,lowerfn.gr.
0 -
-
60:
rl
<Arenaceous sh interval
I
Lower very fn. to lower fn. gr.
flat beddeds s ;
burrow casts few and scattered;
lower shoreface
unit
Rio Salado
Interbedded very fn. gr.ss, arenaceous sh, and
mudstone; (offshore)
Tongye
(section
below
here
not
measured)
I
r
I
Explanation
e burrows
% bioturbated
m root penet.
-carb./coaLy
,x&ross
bedded
.....
;:..,;,.
. . ,,,
.,.
13
The Atarque Sandstone Member
of this report corresponds
of the
in part to the Lower
Gallup, o r the Atarque Member
Gallup, of Molenaar (1973); he also, however, included overlying
nonmarine carbonaceous shales, fluvial channel sandstones, and
thin coal beds in his Atarque Nember. The faunal evidence
presented by Hook, Molenaar, and Cobban(1983) points to a
significant
age
difference
between
the
lower
and
upper
parts
of Molenaar's (1973) Gallup. They recognize their redefined
Atarque as having been deposited during a much earlier regressive
cycle than their Gallup Sandstone and as being separated from
the Gallup by the Pescado Tongue of the Mancos Shale and the
underlying
transgressive
marine.sandstone
unit
which
they
named
3 ) . (Fig.
the Fite Ranch Member of the Tres Hermanos Formation
Overlying the Atarque Member
of the Tres Hermanos Formation
is the coal-bearing Carthage Member. This member
was deposited
on the emergent coastal-plain formed as the sea regressed.
It consists of paludal shales with thin coals, splay sandstones,
and fluvial-channel sandstones. The basal portion is paludal
shale; the contact with the underlying root-penetrated Atarque
Member is sharp. The basal coalzone, where present, lies
3-7 ft above the base and characteristically has a 2-inch-thick
white claystone, formed from volcanic
ash, near the middle.
Immediately overlying this is a sequence of thin, flat-bedded,
burrowed and root-penetrated sandstones (Figs.4 , 5, 6).
These
marginal marine, flat-bedded sandstones have been used as an
aid in identifying the top of the Atarque locally, but the
top is more appropriately placed at the base of the first paludal
14
Fig. 3
Shoemaker Canyon SE s t r a t i g r a p h i c s e c t i o n t h r o u g h t h e u p p e r
Tres Hermanos Formation,thePescado
Tongue of t h e Mancos
Shale,andtheGallup
F' Sandstone i n t h e Sk SW? s e c . 3 4 ,
T. 7 N., 16 W., s o u t h s i d e of Terreo A s t a t i o n .
Scale
7-
Grayishorange ss, s l i g h t c o a r s e n i n g upward from
low f n . g r . a t b a s e t o upper f n . g r . a t t o p ; lower
h a l f f l a t bedded,upp.
h a l f w i t h low t o moderate angle
festoon cross beds
F r i a b l e ,s h a l y , v e r y
30
ower fn. g r . , f l a t bedded ss; burrow c a s t s s p a r s e
-
40
-
50
-
f n . grained ss
Gray t o brownish gray marine sh; limestone concretions
up t o 2 f t in diam. l o c a l l y abundant a t b a s e ; t h i n
bedsofvery
f n . g r . ss. p r e s e n t i n l o w e r p o r t i o n
r
I
3
.r(
U
m
e
Q
2
E!
m
F i t e Ranch
Member
Lower t o upperfn.grained,
f l a t bedded,ledge
forming ss; (marine)
inely-interbedded shaly
ss and arenaceous sh,
e l l o w i s hg r a yt o
duskyyellow;(lagoon
i n f i l l sequence)
ower t o upperfn.grained,ledgerorming
ss, f l a t t o
low a n g l e c r o s s bedded; s c a t t e r e d burrow c a s t s ; ( m a r i n e )
II)
a
U
a
X
to
a
U
H
"-
k
I
inely-interbeddedshaly
ss and arenaceoussh, yellOW&sh
upward; some
r a y t o duskyyellow;slightcoarsening
i o t u r b a t i o n( l.a g o oinn f isl el q u e n c e )
".
Carthage
Member
I
\L
a l u d a ls h , mudstone, and
arbonaceoussh.
s e c t i o n below h e r e n o t measured
.-
8 burrows
a Is.
concretions
15
Fig. 4
Shoemaker CanyonSE stratigraphic section through
lower part of Tres Hermanos Formation, in the
SW% NW% sec. 3 , T. 6N., R. 16W.
Scale
(ft)
T
0 -
(section above has been truncated)
Light olive gray to yellowish gray, lower
tn. gr. s s ;
burrowed, some bioturb.; localiy weathers pale red
Light
brownish
gray
to
gray
paludal
sh,
arenaceous
sh,
with
+edge forming, lower fn. gr.ss; burrowed
Light brownish gray to gray paludal
arenaceous zones
Xedge formmg, lower tn. gr. s s ; a
bioturbation
Carthage
Member
20
-
sh, arenaceous
Gray to light brownish gray paludal
Ledge forming, lower fn. gr.ss; burrowed
Shaly interval (covered)
30
-
40
-
Atarque
Member
Exolanati-
covered
Base
burrows
::..;...:
,..:?&?
...
clay clasts
cross
bedded
16
Fig.
5
Shoemaker Canyon SE s t r a t i g r a p h i c s e c t i o n ,
p a r t of Tres Hermanos Formation i n SW
S5W5
lower
s e c . 30,
T. 7N., R. 16W.
Scale
(ft)
0 -
Carthage
Member
10
'
€(.
-
-
/
B
20
I
>
11
-
Lower f n . g r .
s s ; burrowed,rootpenetrated
Paludal sh; carbonaceouszone
Lower f n .g r .
s s ; burrowed, r o o tp e n e t r a t e d
Paludal sh; carbonaceouszone
Lower f n .g r .
i n lower p a r t
s s ; burrowed;
2 .ft.
above base
some b i o t u r b .
Paludal sh, arenaceous
"
-
Very pale orange
yellowish gray lower to upper
f n .g r .
s s ; c r o s s bedded i n t h i n t o medium s e t s ;
t o p i s l o c a l l y burrowed
Atarque
Member
40
-
............
..'..
w-
Basecovered
-
bioturbated
root penetrated
c a r b /coaly
.
17
Fig. 6
Shoemaker CanyonSE stratigraphic section, lower part
of Tres Hermanos Formation SE+
in S E ' ~sec. 2 0 ,
T. 7N., R. 16W.
4
I
I
Scale
(ft)
0 - ,
~.
,
Light 'gray-yellowish.qray lower
fri; gr. Ss;
burrowed,
bioturbated,
root
penetrated.
I
-
I
Arenaceous sh; (mostly covered)
I
Interbedded lower in. qr. ss and arenaceous
ss is light gray to pale red, burrowed
Carthaqe
Member
Verv finelv interbedded aren.
sh and mudstone, biotur
Coaly zone,0.8 ft thick
1
t
Light brownish gray- grayish orange upper rn.
s s ; large
gr., low to moderate angle cross bedded
(3-4 ft) laminatedss concretions'near top
Atarque
Member
I
+
I
-
L_-_]- Base covered
#
burrows
bioturbated
'
18
and/or carbonaceous shale (Figs.2 and 5).
The middle part of the Carthage Member is largely shale
and is poorly exposedon the quadrangle. A prominent and
widespread fluvial channel complex is present near
top,
the
however, and this sandstone is overlain by a paludal shale with
carbonaceous zones. This upper carbonaceous zone is best exposed
in the NE114 sec. 24, T.7N.., R.l7W., and in adjacent sec.
19.
At this locality it is
2.5 ft thick and is coaly (see Fig.
7).
The carbonaceous zone is capped by a fine grained splay sandstone
which is in turn overlain by a paludal shale sequence. The
200 ft on this
total thickness of the Carthage member is about
quadrangle.
The Carthage is overlain by the marine Fite Ranch Member
of the Tres Hermanos Formation.It is a fine grained, flat
to low-angle cross-bedded sandstone that localLy contains
Inoceramus dimidius at the base. At the measured section in
to 10 ft thick
the NE 114 sec. 24, T.7N., R.17W., it 8is
7,480 is
(Fig. 7); the prominent topographic knob at elevation
capped by the Fite Ranch Sandstone and this isolated outcrop
represents the southwesternmost occurrence of the member.
Tt originally extended an unknown distance to the southwest.
However, because the overlying Pescado Tongue of the Mancos
Shale is only30 ft thick and thinning quite rapidly southwestward
in this area, the turn-around line for the transgression
represented
by
the
Fite
Ranch
Member
and
Pescado of
Tongue
the Mancos Shale, was probably
no more than 10 miles away.
Information
regarding
the
position
of
the
turn-around
line
1Y
Fig. 7
/rite
Shoemaker Canyon SE s t r a t i g r a p h i c s e c t i o n , T r e s
Hermanos Formation i n t h e NE% NWk and Nb NE$
sec. 24, T. 7N., R. 17W.
Ranch
'
Scale
(ft)
Lo -
Grayishorange and paleyellowishbrn.,upr.
V. f n . t o u p r .
f n .g r .
s s ; burrowed,inc.
Ophiomorpha; i o z a l l y Inoceramus
.ldimidiusatbase;*(transgressiveofflapsequence)
P
I '
40
-
.....:.
._..
......
..,..
+
Paludalsh,withcarbonaceouszonenearbase
<Upr.v.
f n .q r .
s s ; t h i n l y lamin. t o f l a q . ;
(overbank 3 s )
P a l u d a l s h , w i t h medialcarb.sh
zone 2 . 5 f t . t h i c k
Fluvialchannel
SS,
low f n .
-
low med. qr.; c r o s s bedded
Paludal s h , a r e n a c e o u ss h ;m i n o rt h i nf l u v i a l
,
(interval mostly covered)
Carthage
Member
I
80
-
120
-
160
-
200
-
'Yellowish graylowerfn.gr.
Paludalshale,arenaceous
5s;
s s ; burrowed & r o o t p e n e t r a t e d
graylower t o upperfn.gr.
i n t h i n t o medium
Atarque
Member
sets
240
-
Arenaceousshale,
and s h a l e
f n .g r .
s s ; low anglecross
"
1
Explanation
-
v
I
?Basecovered
-
root penetrated
carb./coaly
20
could be gained from the subsurface in the Adams Diggings
Omega area to the southeast.
The Fite Ranch is not a typical trangressive marine sandstone.
Tt is of widely varying thickness locally-from
2 to 10 ft-and
in places cannot even be recognized such as in 114
the NE
sec. 34, T.7N., R.16W. Most important is the fact that it does
on this quadrangle.
not fine upward at the sections examined
Hook, Molenaar,and Cobban (1983) have offered the explanation
that it is a transgressive offlap sequence in long
that
stillstands of the shoreline allowed extensive progradation
of
sand bodies to take place. These episodes were punctuated by
relatively rapid advances of the shoreline which transgressed
its back barrier and/or lagoonal deposits and then assumed a
stillstand in a more landward position.
The southwesternmost occurrence, (or truncation point), of
the Fite Ranch Member is an erosional remnant
in the NE 114
sec. 2 4 , T.7N., R.17W.
The overlying Pescado Tongueof the
Mancos Shale has been eroded off and its southwesternmost
occurrence is approximately two miles to the northeast in sec.
8 (see accompanying geologic map).
The significance of these
erosional truncation points is that the authors of the redefined
Tres Hermanos Formation (Hook, Molenaar, and Cobban, 1983)
stated that the presence of the Fite Ranch Member and/or the
Pescado
Tongue
shall
determine
the in
area
which
the
Tres
Hermanos nomenclature shall be used. Landward equivalents to
the southwestwere, as previously mentioned, designated as
the Atarque Sandstone and the Moreno Hill Formation.
In the
21
present study it was considered appropriate to extend the
Tres Hermanos nomenclature southwestward around the ofend
the topographic feature upon which the Fite Ranch truncation
occurs. This carries the nomenclature throughout the Shoemaker
Canyon SE quadrangle and into the eastern part of the adjacent
Mesita de Yeso quadrangle; the latter quadrangle becomes the
one in which the change in stratigraphic nomenclature
takes place (Anderson, 1 9 8 2 ) .
Where the Atarque appearsin
outcrops, 12 miles to the west of the Shoemaker Canyon
SE
quadrangle, it is of formational rank. To relate this nomenclatural
change
to a
line
rather
than area,
an the
following
adopted by the New Mexico Bureau
of Mines
east
ofN " 3 2 and
northof the
Jaralosa
and
Draw
has
Mineral
been
Resources;
Lobe
of the
North Plains lava field the Tres Hermanos nomenclature will
be used;
west
N " 3 2 and south of the basalt flow the names
of
Atarque Sandstone and Moreno Hill Formation will be used for
this interval. This nomenclature change corresponds with a
change in coal-field terminology. The Tres Hermanos outcrop
defines the southern and southwest edge of the Gallup-Zuni
coal field. Coal occurrences in the Moreno Hill Formation
to the south and west are part of the
Lake
Salt
coal field
(Anderson, 1982b) ,
The Pescado Tongue of the Mancos Shale separates the Fite
Ranch Member from the F Member
of the Gallup Sandstone. The
Pescado i s characterized by large limestone concretions at the
base and verythin, fine grained sandstones interbedded with
shale in the lower one third to one half. No fossils
were
It thins in a
collected from this interval on the quadrangle.
22
southwesterly direction and at its southwesternmost outcrop in
the E 112 sec. 8 , T.7N., R.16W., it is about30 ft thick.
Molenaar (1973) correlated the Pescado with the lower of
half
the D-Cross Tongue of the Mancos Shale.
of the Cretaceous section
The Gallup Sandstone, at the top
in the Shoemaker Canyon
SE quadrangle, is about200 ft thick
and is subdivided into the
F Member at the base overlain by an
unnamed
coal-bearing
member
in
the
middle,
and
the
Torrivio
Member at the top.
The F inember (Hook, Molenaar, and Cobban,
1983) is -45-50
feet thick in the Shoemaker Canyon
SE quadrangle. It is a
regressive coastal-barrier sandstone that marks a transition
in the Zuni Basin
which
the
deposited
from
underlying
to
a
an
open-water
Pescado
deltaic
and
Tongue
environment
in
marine
of
the
coastal-plain
Mancos
Shale
environment
in
was
which
the overlying midclle and upper parts of the Gallup were deposited.
The lower half of the
F.member is
flat-bedded
light-gray
very
fine to fine-grained sandstone containing dark-gray silty and
shaly partings. This part of the member is poorly exposed
except
The
for
upper
the
part
basal
5-10 ft
of
the
which
commonly
member
i s mostly
form
fine-grained
weak
ledges,
light-gray
sandstone that is somewhat more resistant than the lower
part and is flae-bedded and crossbedded.In sec. 4 , T.7N., R.l6W.,
the top of the member consists
of a bed about12 ft thick
of light-gray fine-grained sandstone containing numerous burrows
at the top, underlain by an interval about
6 ft thick of
nonresistent sandstone that is shaly and slightly carbonaceous.
23
The basal part of the
F member also is burrowed locally. The
F member grades downward into the underlying Pescado Tongue
of the Mancos Shale through an interval5-10
of ft.
The middle, coal-bearing member of the Gallup Sandstone
is about 100 ft thick in the Shoemaker Canyon
S E quadrangle.
At the base is a fluvial channel-fill sandstone bed 30-35 feet
thick that rests with a sharp erosional contact on sandstone
of the F member. The fluvial sandstone is very light gray to
very light yellowish-gray, mostly fine-grained becoming somewhat
coarser at thebase, crossbedded, and forms prominent rounded
ledges and cliffs.
A variable sequence of fluvial and paludal rocks comprises
the rest of the coal-bearing member. Included in the sequence
are dark-gray silty and sandy claystone, fissile brown carbonaceous
shale, light-gray siltstone, and light-gray and light yellowish-gray
crossbedded and ripple-marked sandstone. Dark reddish-brown
ferruginous concretions are common in some of the shale and
claystone beds. Pxesent in the quadrangle are at least four
beds of coal separated by intervals a few inches to several
feet thick of shale, claystone, and sandstone. Individual coals
commonly are 1-2 feet thick, thickening locally where two or
more beds merge. The lowest of the coals rests directly
on,
or within a few inches of the basal fluvial sandstone. The
two next higher coals contain identifying, partings
0.2-0.4
ft thick of grayish-white claystone. The partings are thin beds
of altered volcanicash, and they are useful
in correlating
the coals in an area of several square miles in this part of
24
the Zuni Basin.
The Torrivio Member of the Gallup Sandstone
(named-the
Torrivio Sandstone Memberby Molenaar, 1 9 7 3 ) is about 4 0 - 5 0
feet thick. It crops out only in the extreme northeastern
corner of the quadrangle where it consists of ledge-forming
grayish-red fine- to coarse-grained crossbedded feldspathic
sandstone. Molenaar ( 1 9 7 3 ) describes the unit as a channel-fill
sandstone
complex
deposited
by
low-gradient
braided
streams.
Coal Resources
Coal in the Shoemaker Canyon SE quadrangle is classed as
of samples
high volatile bituminousC, based on the analyses
of
fresh
coal
from
a in
bed
the
Gallup
Sandstone
northwest of the quadrangle (Sears,1 9 2 5 , p . 5 0 ) .
a
few
miles
Table 1
shows the analyses
of two samplesof weathered coal from a coal
bed in the Gallup Sandstone exposed in a road cut about a mile
north of the Shoemaker Canyon
SE quadrangle. The analyses show
ash contents of6 . 7 to 10.1 percent, respectively, and sulfur
contents of 0.6 percent for the weathered
coal, which is slightly
( 1 9 2 5 , p. 5 0 ) for the
less than the values reported by Sears
fresh coal from about the same horizon. Heat values
of
9017
and 9 4 7 1 BTU/lb on the
as-received
basis
for
the
weathered
11000 BTU/lb
coal (table I) compare with an average of about
( 1 9 2 5 , p. 5 0 ) .
for the fresh coal as reported by Sears
The
weathered condition of the coal probably accounts for the low
heat values reported
on table 1.
Estimated resources of bituminous coal in the Shoemaker
25
Canyon SE quadrangle total 1.4 million short tons. Table 2
lists the resources by township according to thickness and
reliability categories established by U.S.
the Bureau of Mines
and the U.S. Geological Survey (1976).
The estimates are based
on coal-bed measurements made at five places in the northeastern
3 4 , T.8N., R.l6W., and in secs.
part of the quadrangle in sec.
3 and 4 , T.7N., R.16W.
A l l the beds for which resources are
estimated are in the coal-bearing member
of the Gallup Sandstone
Coal beds and lenses in the Carthage Member
of the Tres Hermanos
Formation are too thin and discontinuous for resource estimates.
Acknowledgements
The writers wish to express their appreciation to Dr. Stephen
C. Hook and Dr. WilliamA. Cobban for their assistance in fossil
identification. The drafting assistance of Teresa
A. Mueller and
A special
James Brannan is also hereby gratefully acknowledged.
thanks
.also
.goes to
This
work
was
Nanette
carried
Dynan,
out
typist.
jointly
by
New the
Mexico
Bureauof
Mines and Mineral Resources and U.
theS. Geological Survey; the
U. S. Bureau
of Indian Affairs supported the work within the
Ramah Indian Reservation boundary.
Table 1.-Analyses
of .coal from a bed i n t h e Gallup Sandstone exposed i n a road c u t i n
sec. 33, T. 8 N., R. 16 W., Cibola Co., New Mexico.
the SF&
Forms of analysis: A, asreceived; B, moisturefree; C, moisture and ash
Analyses by t h e U.S. Department of Energy, Feb. 18, 19801
Heating
Ultimate
Proximate
[Inpercent.
free.
Laboratory
no.
K98773
Form
of
Moisanalysis t u r e
A
B
C
K98772
A
B
c
I-
Volatile
matter
10.6
-
36.7
U.3
I
_
Fixed
carbon Ash
-
4.7
3.9
6.7
7.6
0.6
0.6
10.1
11.3
46.3
47.7
53.7
37.0
W.7
45.0
45.1
50.7
54.9
Hydrogenl
0.6
0.7
0.8
42.6
W.0
Sulfur
-1
0.7
Carbon
I 54.7
Nitrogen
61.2
1.1
1.2
4.4
69.0
1.4
4.9
4.1
4.4
57.7
1.2
65.0
70.3
1.5
1.4
thermal
unrtsl
0qgen
28.8
21.7
24.5
1
,
29.0
23.1
21.4
9017
10085
1
,11365
9471.
11548
10673
Description of samples: K98773, chip sample, upper bench 0.6 f t thick above a light-gray
claystone parting; K98772, chip sample,lower bench 1.4 f t thick below a light-gray
claystone parting.
27
Table 2 . E s t i m a t e d c o a l r e s o u r c e s i n t h e
Gallup Sandstone, Shoemaker Canyon SE
quadrangle, Feb. 1, 1983.
[
I
nthousands
of shorttons.
All values rounded.
1,800shorttons/acre
f t used
i n the calculations1
Thickness of c o a l i n bed
Township
and r h g e
1.2-2.3
f t thick
Measured Indicated
2.3-3.5
11
T o t a l Measured IIndicated
T. 8 N., R. 16 W.
120
180
300
T. 7 N., R. 16 W.
440
140
580
Totals, rounded
860 320 560
f t thick
1
I
Total
in the
T o t a l township
95
-
95
400
370
20
390
970
470
20
490
1,400
I
REFERENCES
Anderson, 0. J., 1982a, Geology and Coal Resources
of the
Atarque Lake quadrangle, Cibola County, New Mexico:
New
Mexico
Bureau
of
Mines
and
Mineral
Resources
Open-file
report 167.
, 1Y82b, Geology and Coal Resources
of the Mesita de Yeso
quadrangle, Cibola County, New Mexico: New Mexico Bureau
of Mines and Mineral Resources Open-file report
171.
Campbell, Frank,1981, Geology and Coal Resourcesof the Dyke
and Cerro Prieto quadrangle: New Mexico Bureau
of Mines
and Mineral Resources Open-file report 144.
Hook, S. C., and Cobban,W. A., 1977, Pycnodonte newberryi
(Stanton) common guide .fossil
in the
Upper
Cretaceous
of
New Mexico: New Mexico Bureau of Mines and Mineral
Resources Annual Report1976-77, pp. 48.
Hook, S. C., Cobban,W. A., and Landis, L . R., lY80, Extension
of the intertongued Dakota Sandstone
- Mancos Shale
Terminology into the Southern Zuni Basin: New Mexico Geology,
vol. 2, no. 3 .
Hook, S. C., Molenaar, C. M., and Cobban,W. A., 1983,
Stratigraphy
and
revision
of Upper
rocks of west-central
Cretaceous
New
paleontology
and
Cenomanian
to
Mexico,
in Contributions
stratigraphy
of New
Turonian
to
mid-
Mexico--
part TI, Kook, S. C., compiler: New Mexico Bureauof Mines
and Mineral Resources circular
no. 185.
Laughlin, A . W., Brookins, D.
G.,Damon, P. E.,
and Shafigullah,
of the Central Jemez
M., 1979, Late Cenozoic volcanism
Zone, Arizona-New Mexico: Isochron/West no.25, p . 5.
Maxwell, C. H., and Nonini, L. G., 1977, Written communication
resource information for the Zuni Indian Reservation, New
Mexico.
McClellan, M.W., and others, 1983, Middle Turonian and younger
Cretaceous rocks, northern Salt Lake coal field, Cibola
and
Catron
Cretaceous
Counties,
paleontology
New
in Contributions
Mexico,
and
stratigraphy
o f New
to
mid-
Mexico--
part 11, Hook, S. C., compiler: New Mexico Bureauof Mines
and Mineral Resources circular
no. 185.
Nolenaar, C. M., 1Y73, Sedimentary facies and correlation
of
the Gallup Sandstone and associated formations, Northwestern
New
Mexico,
in
Four
Corners
Geologic
Society
Memoir
Book,
1973, p. 85.
Owen, D. E . , 1966, Nomenclature of Dakota Sandstone (Cretaceous)
in San Juan Basin, New Mexico and Colorado:
h e r . Assoc.
of Petroleum Geologists Bull., vol.
50, no. 5 , p . 1023.
Sears, J. D., 1925, Geology and coal resources of the Gallup-Zuni
Basin, New Mexico: U.S. Geological Survey Bull. 767
U.S. Bureau of Mines and U.S. Geological Survey,1976, Coal
Resource Classification System
of the U.S. Bureau of Mines
and the U.S. Geological Survey: U.S. Geol. Surv. Bull.
1450-B.
~~~~
SHOQaKER
CANYON SE
~
*"ADPANGLE,
LAND AND
"*NEPAL OWNERSHTP
llumollLoad
or
action numLXsr
PaLOOL
Tovnehlp
8N
8.3CtiO"
16U
8N
17W
7N
16W
Parcel
ailroad
Grant
__
other
private
OX
state of
New Mexico
30
Indian tru.r,
cribal.
Or WlfMraWI
All
'All
32
All
33
All
34
All
1052199
35
All
567459
34
All
30730023
35
All
LI-NH13-1001
36
a11
1223640
Y
2
All
1223704
X
3
4
All
P W 2198
X
All
30660179
X
and canals
All minerals, ditches
5
All
P W 2198
X
All
6
NEC
30650200
NWk
491234
Coal, ditchesand canals
SWk
470978
Coal, ditches and canal9
I
7
8
LI-NH13-1001
minerals
31
Ditches and canals
X
1223641
IT-NH13-1001
X
All
minerals
All
minerals,ditches
x
All minerals, ditches and canal9
X
All minexals
Ditches and canale
Dicoheo and canals
All minerals
minerals
Oilrga8,cOal;ditcheaand canals
~ l minerals,
l
ditches and canals
SEk
955305
A11
P W 2198
X
All
Ditches
minerals
NEC
1042054
NWC
1042214
X
X
SWC
1042215
X
Ditches
SEk
1042213
X
Ditches andcanals
X
All
andcanals
Ditches and canals
andcanals
minerals
?.l1
P W 2198
10
N 1
1077253
11
All
P W 2198
X
All
14
NWi
954638
X
Ditohes andcanals
SWII
954637
X
Ditches andcanals
NLI
SF064554
Slr
P W 2198
X
All
16
All
1223103
17
N 1
PTa 2198
X
R11
18
NE+
1042216
X
Ditches
and
NWII
1042055
X
Ditches
andcanals
swk
1042217
X
Ditches
andcanals
SEII
1095018
Ditches
andcanals
All
P W 2198
X
X
All
9
15
19
20
and
canals
-none-
All minerals, ditches and canals
X
minerals
Surface and mineral*
minerals
Ditches andcanals
X
minerals
canals
minerals
NE4
1043513
X
Ditches
andcanals
NWk
1043514
X
Ditches
and
SWC
1043515
Ditohes
andcanals
All
oanals
SE'i
1043512
X
X
21
N l
P W 2198
X
22
NLI
1096622
SWC
965304
X
Ditches and canals
SEC
965305
X
DiZchas and canals
23
All
P W 2198
X
All
26
NWC
1037496
X
Ditches
SWC
1037493
X
Ditches and canals
17
All
P W 2198
28
N E ~ N E ~ 30660179
X
Ditches andcanals
minerals
Ditches and canals
X
x
minerals
andcanals
N 1 minerals
All mherals
NWkNEk
934208
X
Ditches
and
canals
NLINWC
934208
X
Ditches
andcanals
SWkNWk
934208
X
Ditches and canals
SEIINWk
IL-175
X
Ditches and sanals
WLISWk
IL-175
X
Ditches
WUEk
934207
x
Ditshos and san.1~
ELISWC
934207
X
Ditches and canals
ELISE$
934213
X
Ditches and canals
SLINEk
934213
X
Ditches and canals
29
All
P W 2198
X
AI1
30
NE%
1043510
X
Dicohes
NWC
1043511
X
Ditches andcanals
SWk
1095019
X
Ditches and canals
SBC
1043185
X
Ditches and aanals
andcanals
minerals
andcanals
>
7N
31
All
P M 2198
32
All
1223704
33
All
P M 2198
34
NE4
1095015
Nnc
1095014
SWh
1095016
X
X
SE'i
1095017
35
All
PI0 2198
1
All
2
All
1223704
3
All
670394
10
NE&
905129
X
Nnc
1105323
X
swc
905125
X
SEh
1105323
All
670394
x
X
11
670394
X
x
X
X
NE^
1078497
we
905128
X
slr
1104718
x
13
All
670394
X
14
ELI
1078497
X
WLIWLI
1078497
X
15
A11
670394
X
22
All
1052426
23
A11
670394
X
24
A11
1067470
X
25
All.
670394
X
26
NLI
1078497
X
Nnsuc
1105323
X
slrswc
1105323
X
SW'rSEk
1105323
NWSW'I
905122
x
x
X
12
X
30660015
6N
6N
16W
17H
x
NlrSE'r
905122
SE~SE'~
905122
27
All
670394
X
34
All
1067470
X
35
a11
916727
x
36
All
1123703
2
Nnc
986677
ELISHI(
1223974
3
All
670394
4
NLI
1081582
X
SElr
1081582
X
NlrSWlr
1081582
X
SE'rSW'r'
1081582
x
X
X
x
X
X
swcsw'r
IL 158
5
All
670394
6
NEIINE~
1088664
X
SLINEli
1088664
X
X
X
SECNWi
1088664
X
Slr
1088664
X
NncNEc
648510
X
NlrNUh
648510
X
SW'INnk
648510
7
a11
670394
X
8
All
1056136
X
9
A11
670394
X
10
All
1056136
x
11
All
670394
X
I4
15
16
All
1056136
All
670394
x
x
A11
1223973
17
A11
670394
X
18
A11
1056136
X
I
A11
670394
X
X
X
2
3
10
NECNEC
1123974
X
WL1,NEC
1223974
X
canals
and
Ditches
Ditches and
WLI
1223974
X
Ditches
FM&~*B
andcanals
WLISEII
1103924
Y
All ninerqls, ditchoa andoanals
NEhSE'r
1103924
X
R11
SECNEC
1103924
X
All minerals, ditohesand canals
SchNh
1223914
All
670394
NL1
1095069
X
X
minerals,ditohes and canal8
Ditches
andcanals
Ditches
andcanals
All minerals, ditches and
camla
~ 1 minerals,
1
ditches and omdils
S'rNHIIofSWC 1095069
SUIISEC
1095069
~ 1 nineral.la,
1
dirshos and canals
NLISEC
158926loriginal)
Ditches and canals
NECSWlr
90513Q(supplenientelI
Ditches and canals
SECSEC
30680015
11
All
670394
X
Ditches end canals
12
All
1078908
X
Ditches and canals
13
All
670394
X
Ditches and Canals
14
All
1067470
X
Ditches and EQnPls
15
All .
670394
X
Ditches
Oil,gas,coaliditches and canals
'
andcanals
Composite Section
30'
34"52'30"
O
DESCRIPTION OF MAP UNITS
LKgt
T 8 N
I
Qal
T 7 N
/
A"
,3861
J
c
Y-
0
0
I
0
A l l u v i a ld e p o s i t su n d i f f e r e n t i a t e d ;c l a y ,s i l t , , s a n da n d
gravelinarroyos,floodplainsand
on g e n t l e slopes.
I
Qcl
Colluvium,landslide
Qb
B a s a lft l o w so; r i g i n a t i n g
from c e n t e r s t o east i nt h eN o r t h
K-Ar
Plains lava field; olivine tholeite in composition with
age of 1.41 m-y. (Laughlin,Brookins,
Damon, and S h a f i q u l l a h ,
1979).
Kgt
T o r r i v i o Member of GallupSandstqne (Upper C r e t a c e o u s ) ; l e d g e
t o very coarse grained, crossbedded,
forming grayish red, fine
extreme n o r t h e a s t c o r n e r
feldspathicsandstone;presentonlyin
of t h e q u a d r a n g l e ; u n i t r a n g e s
up t o 40 f t t h i c k l o c a l l y .
wc
Coal-bearing member of
Gallup
Sandstone
(Upper Cretaceous);
a t base i s a 30-35 f t t h i c k f l u v i a l c h a n n e l s a n d s t o n e t h a t
rests w i t h s h a r p e r o s i o n a l c o n t a c t
on t h e F member; above
is variablesequenceoffluvial
and p a l u d a l r o c k s i n c l u d i n g
dark g r a y s i l t y - s a n d y c l a y s t o n e ,
f i s s i l e brown carbonaceous
shale, light gray siltstone,
and l i g h t y e l l o w i s h g r a y crossbedded and ripple marked sandstone; ferruginous concretions
coal beds
common i n s h a l e and claystonebeds.Containsfour
ranging up t o 2 f t i n t h i c k n e s s ; lowest c o a l rests on basal
f l u v i a l s a n d s t o n e ; two n e x t h i g h e r coals c o n t a i n d i s t i n c t i v e
0.2-0.4 f t t h i c k
g r a y i s h - w h i t ec l a y s t o n e( t o n s t e i n )p a r t i n g s
Coal-bearing member about 100 f t t h i c k .
Kgf
F member ofGallupSandstone
(Upper C r e t a c e o u s ) ; l i g h t g r a y ,
very fine t o finegrainedsandstone;
lower p a r t c o n t a i n s d a r k
part somewhat more r e s i s t a n t ,
g r a y s i l t y and shaly partings; upper
numerous burrows;grades
w i t h more d i s t i n c t c r o s s b e d d i n g , a n d
downward i n t o t h e P e s c a d o Tongue of t h e Mancos Shale through an
i n t e r v a l of 5-10 f t ; t o t a l t h i c k n e s s of u n i t a b o u t 50 f t .
KmP
Pescado Tongue of Mancos Shale (Upper C r e t a c e o u s ) ; l i g h t t o
medium g r a y and brownish gray marine shale; contains large
base,
(up t o 2 f t i n diameter) limestone concretions near the
and very thin fine-grained sandstone beds
i n lower h a l f ; u n i t
about 30 f t t h i c k .
Kthf
F i t e Ranch Member of Tres Hermanos Formation (Upper Cretaceous);
yellowish gray t o grayish orange, upper very fine
t o upper finegrained sandstone; lower p a r t commonly b i o t u r b a t e d and c o n t a i n s
Inoceramus dimidius;upper p a r t coarser g r a i n e d , f l a t t o low angle
crossbedded,andburrowed.Unit
v a r i e s from 2 t o 10 f t i n t h i c k n e s s .
Kthc
Carthage Member of Tres Hermanos Formation(UpperCretaceous);
p a l u d a l s h a l e and mudstone, carbonaceous shale with minor, coal,
and f l u v i a lc h a n n e ls a n d s t o n e .S h a l e s
are gray t o l i g h t o l i v e
4-6 f t above base locally has
up t o
gray;carbonaceouszone
1.6 f t o f coal i n 2 beds separated by 0.2 f t t h i c k w h i t e c l a y s t o n e . Maximum t h i c k n e s s onquadrangle-200
ft.
bosol t
~
II;
!
3359
w / tonstein
m
1 400 000
FEET
.i
mass, or torevablocks.
t
Y-
Lo
w
50'
3357
t
Y-
0
0
(u
,d.
rl
r
carb.
~
cool
'354
L.
a
Q
Q
4
3
+
v-
?
Ktha
Atarque
Sandstone
Member of Tres Hermanos Formation (Upper
Cretaceous); grayish orange
t o very pale o r a n g e , v e r y f i n e
to
upper fine grained marine sandstone; coarsens
upward; w e l l
i n d u r a t e d ,g e n e r a l l ym a s s i v e ,c l i f f
former; burrowspresentin
lower a n d m i d d l e p a r t s ; f o s s i l i f e r o u s - s m a l l b i v a l v e s , i n m i d d l e
part; upper p a r t strongly crossbedded predominantly of trough
typeand i s c o n t r a s t e d by i t s l i g h t e r color. Maximum t h i c k n e s s
on quadrangle about 60 f t .
mr
R i o Salado Tongue of Mancos Shale (Upper C r e t a c e o u s ) ; medium t o
dark gray and brownish gray marine shale, silty shale, calcareous
a t thevery
s h a l e and c a l c a r e n i t e , w i t h t h i n i n t e r b e d d e d s a n d s t o n e
top; weathers t o g e n t l e or moderately steep s l o p e s which are
generally covered by c o l l u v i u m , t a l u s , o r l a n d s l i d e d e b r i s ; base
not exposed; calcarenite beds and calcareous shale with an underl y i n g zone containingabundantPycnodontenewberryi(Stanton)
occur about 35 f t above t h e base; calcareous zone is Greenhorn
Member) equivalent;upper100
f t of t h e
Limestone(BridgeCreek
tonguecontains numerous l i m e s t o n e c o n c r e t i o n z o n e s ; a s s o c i a t e d
with the concretions locally
are t h e ammonites Mammites depressus,
Mammites nodosoides, Proplacenticeras
, and
Neoptychites
cephalotus; also found i n t h i s a s s o c i a t i o n are Ostrea E., v a r i o u s
b i v a l v e s , T u r r i t e l l a and othergastropods.Thicknessoftongue
e s t i m a t e d a t 240 E t .
Kdt
Twowells Tongue ofDakota Sandstone (Upper Cretaceous);yellowish
gray t o pale o l i v e , v e r y f i n e
t o upper fine grained, shallow
water
marine sandstone; lower
part veryfinegrained,
commonly burrowed
and b i o t u r b a t e d , w i t h t h e s e f e a t u r e s c o n t i n u i n g i n t o t h e m i d d l e ,
shalypart;upper
part is crossbeddedinthin
sets and/or wavy
all
bedded w i t h t h i n s h a l e i n t e r b e d s ; l o c a l l y f o s s i l i f e r o u s i n
parts, but mainly middle
and u p p e r ; f o s s i l s c o n s i s t o f
Pycnodonte
kellumi, and small ( r e l a t i v e t o t h o s e i n t h e P a g u a t e
Tongue)
Exogyra l e v i s ; also found l o c a l l y i n a s s o c i a t i o n w i t h t h e s e
is Exogyra triqeri (Coquand). Maximum thicknessonquadrangle
e s t i m a t e d a t 20-22 f t .
KmW
WhitewaterArroyo
Tongue of Mancos Shale (Upper Cretaceous);
g r a y t o medium dark gray marine shale; slope former, base not
i s a 15inchthickwhitetoorange
exposed;nearthemiddle
well exposed i n t h i s area; s e l e n i t e
weathering bentonite bed not
c y r s t a l s common; t h e r e l a t i v e l y large o y s t e r Exoqyra t r i g e r i is
locallyabundant;estimatedthickness
of u n i t is 60 f t .
!
17'30"
52
7 N
6 N
'51
50
Bridge Cr.
Ls. Beds
t
+
t
c
MAP SYMBOLS
bentonite
3
9
J
,
"
"
Contact, dashed where approximate or inferred
8
4* 45'
3'
.\'Td
'
Control by USGS and N O W N O A A
by photogrammetrlc methods from aerlal
photographstaken 1 9 7 1
2
"
loo0
F d d checked 1972
-
-1
1
- - -~ Topography
0
I
2000
3000
4000
5000
6000
1
I
k
I
k
I
1
H
b
1000
H H H
Prolection and 10,000-foot grld tlcks. NWJ M e x ~ c o
coordlnate system, west zone (transverse Mercator)
1000-metre UnlversalTransverse Mercator grtd tlcks,
zone 12,\shown in blue. 1929 North Amencan datum
1 MILE
0
M
5
H
H
0
H
-
7000 FEET
I
1 XILOMETRE
!
J
CONTOURINTERVAL 20 FEET
DOTTED LINES REPRESENT 10-FOOT CONTOURS
NATIONAL GEODETIC VERTICAL DATUM OF 1929
Prlrnary Llght-duty
road,
hlghway,
hard
surface
3%
"%;eL
"Y--""-
InterstateRoute
D = downthrown
-5
Unimproved
road
~
[
jU
S Route )
; : 1
====_;_=_
<"',
Y3'
State Route
Flne red dashed llnes lndkcate selected fence hnes
UTM GRID AND 1.972 MAGHETIC NORTH
DECLINATION RiT CENTEX OF SHEET
Fault,U=upthrown,
_
i
Z%
Secondary hrghway,
hard surface
0
hard or
~mprovedsurface ==._
-.=-___C__n
/
a
ROAD CLASSiFlCAPlON
SCALE 124000
MER CANYON SE, N. "EX.
N3445--W10830/7,5
Strikeanddip
of beds
\
Measured
section
referred
to
in
text
-c-
Baseofprincipal
coal in Kgc
1972
AMS 4253 I SE-SERIES
V331
-
A
1
A'
A
,Kthf
7,500
7,300
Kthc
u
k
[r
7,100
Kmr
w
6,900
-
6,700
-
W
,Kdt
.
Kmw
Kmr
- 6,900
>
X
In
/Kdt
I
Kmw
.- 6,700
b y ORIN J.
NDERSQN a n d
1983
1