Preliminary Geologic Map of the Angus Quadrangle
NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES A DIVISION OF NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY
105°45'0"W
431000
432000
105°42'30"W
433000
434000
435000
436000
105°40'0"W
437000
438000
439000
440000
105°37'30"W
441000
442000
3707000
Mapped and compiled by Geoffrey Rawling
3707 000
33°30'0"N
Tsv
17
36
Tsv
Kmv
29
77
77
Tm
15
38
82
42
QHa
41
88
3706000
Qvf
42
af
66
22
Tad
42
Kmv
68
85
Tbs
10
85
78
Tad
73
Kmv
10
Tm
24
Tcm
af
3705000
32
90
85
32
11
Tsv
Tcm
Tsv
53
Tdsc
QHa
Tsv Tcm
Qvf
Tcd
Tad
25
Kmv
Kmv
76
Qvf
Tsv
Tcm
Qvf
3703000
Qvf
78
19
Tad
90
Tad Tad
Tad
85
3702000
QHa
QHa
84
Tdsc
10
14
Qaf
Tm
Tad
Kmv
Qaf
Qaf Qbt2
Qbt2
Qaf
Qaf
Qbt2
Qbt2
82
Qaf
16
74
Tad
Qbt1 Qaf
32
7
Tcm
Qbt2 QHa
78
Tbs
Tdsc
Qbt2
32
88
Qbt1
Qbt2 Qbt2
Qbt1
Qbt1
Tad
82
10
30
Qaf
21
3
3700000
84
14
88
27
Qaf
QTg
238
QTg
24
73
24
18
Kmv
3700 000
19
32
Tm
Tad
Tcm
Tad
Kmv
9
22
QTg
9
8
QTg
85
6
Qbt1
Qaf
85
18
3699000
Qaf
83
14
16
80
Qbt1
Kmv
70
7
16
10
Qaf
Qbt2
Qbt1 Qaf Qaf
3701 000
Tm
18
7
Qbt2 Qaf
Qaf Qbt2
Qaf
Qbt2 Qbt2
86
3699 000
65
52
Tad
Tad
Tad
20
17
18
69
Tad
71
77
78
Tcm
Tcm
QTg
16
Tcm
3698000
3698 000
12
Qvf
Qvf
Qvf
33°25'0"N
QHa
6
20
Tm
Kmv
Qaf
88
33°25'0"N
Kmv
Tcm
61
84
Qvf
21
3697000
88
Qvf
Qaf
QHa
28
23
3697 000
Qvf
Qvf
22
57
Tsv
13
86
22
Tm
72
daf
4
af
QTg
QTg
Qvf
22
78
af
QHa QHa Tad
14
af
Tcm
Kmv
15
17
87
78
86
88
af
15
QTg
Tsv
QHa
Qvf
Qvf
QHa
3694000
20
Qvf
Tsv-tf
70
17
10
431000
432000
433000
434000
435000
105°42'30"W
436000
1
CAPITAN
NEW MEXICO
NOGAL
PEAK
SIERRA
BLANCA
PEAK
ANGUS
ANGUS
RUIDOSO
FORT
STANTON
RUIDOSO
DOWNS
QUADRANGLE LOCATION
This draft geologic map is preliminary and will undergo revision. It was produced
from either scans of hand-drafted originals or from digitally drafted original maps
and figures using a wide variety of software, and is currently in cartographic production.
It is being distributed in this draft form as part of the bureau's Open-file map series
(OFGM), due to high demand for current geologic map data in these areas where
STATEMAP quadrangles are located, and it is the bureau's policy to disseminate
geologic data to the public as soon as possible.
After this map has undergone scientific peer review, editing, and final cartographic
production adhering to bureau map standards, it will be released in our Geologic Map
(GM) series. This final version will receive a new GM number and will supercede
this preliminary open-file geologic map.
DRAFT
0.5
1000
0
1
Magnetic Declination
April, 2006
9º 13' East
At Map Center
@sr
Pg
Psa
18
10
437000
438000
105°40'0"W
QTg
@sr
Kd
0
1000
2000
0.5
3000
1 MILE
4000
5000
0
Qg
6000
23
14
Pg
Kd
Qvf
439000
3694 000
Qvf
Qvf
1:24,000
NOGAL
Kd
Kd
Km
4
18
Qaf
17
Qg
29
Qet2
Km
15
18
Psa
3695 000
Qet1
20
7
Km
24
Base map from U.S. Geological Survey 1963, edited in 1982.
1927 North American datum, UTM projection -- zone 13N
1000-meter Universal Transverse Mercator grid, zone 13, shown in red
CHURCH
MOUNTAIN
QTg
Qvf
105°45'0"W
Qaf
31
15 14
83
Tsv-tp
33°22'30"N
QTg
11
10
Pg
Qaf
Qet2
Qvf
QHa
Qvf
Km
15
Kmv
Tad
18
Qaf
75
9
14
62
Kmv
90
Km
15
9 68
80
3693000
11
15
24
Kd
@sr
34
Qaf
Qet2
17
Tcm
55 90
Tsv
Tsv
17
QTg
7
Kd
Tad QHa
17
Td
Tsv
15
Psa
14
10
QTg
Tsv
Tsv
10
Tad
4
Kmv
69
Km
15
QTg
af
Kmv
Qvf
Qvf
77
Kmv
Kmv
QTg
20
9
77
54
4
Tad
16
28
7
3696 000
17
7
Qvf
QHa
Tm
4
20
5
Tm
75
30
3695000
Qvf
10
Kmv
14
@sr
Pg
Psa
3693 000
Qvf Pg
440000
33°22'30"N
441000
442000
105°37'30"W
Geologic map of the Angus quadrangle,
Lincoln and Otero Counties, New Mexico.
7000 FEET
May 2004
1 KILOMETER
by
Geoffrey Rawling 1
CONTOUR INTERVAL 40 FEET
NATIONAL GEODETIC VERTICAL DATUM OF 1929
New Mexico Bureau of Geology and Mineral Resources
Open-file Map Series
1
NMBGMR, 801 Leroy Pl, Socorrom, NM, 87801
OFGM 95
COMMENTS TO MAP USERS
Mapping of this quadrangle was funded by a matching-funds grant from the STATEMAP program
of the National Cooperative Geologic Mapping Act, administered by the U. S. Geological Survey,
and by the New Mexico Bureau of Geology and Mineral Resources, (Dr. Peter A. Scholle,
Director and State Geologist, Dr. J. Michael Timmons, Geologic Mapping Program Manager).
New Mexico Bureau of Geology and Mineral Resources
New Mexico Tech
801 Leroy Place
Socorro, New Mexico
87801-4796
[505] 835-5490
http://geoinfo.nmt.edu
This and other STATEMAP quadrangles are (or soon will be) available
for free download in both PDF and ArcGIS formats at:
http://geoinfo.nmt.edu/publications/maps/geologic/ofgm/home.html
Qet1 – Upper terrace deposit of Eagle Creek (upper Pleistocene) - Poorly sorted
alluvial deposits composed of interstratified fine to coarse sand and sandy gravel of
rounded cobbles and boulders. Deposit forms a terrace whose tread is preserved and is
3 – 4 meters above present stream grade. In Eagle Creek canyon between the west end
of Gavilan Ridge and Alto reservoir the terrace tread is continuous with remnants (?)
of a strath terrace beveled on bedrock of Mancos Shale and Mesa Verde Group
sandstones and shales. Largely mapped from aerial photographs. Thickness: 0 to 5 (?)
meters.
Qg – Stream gravel deposits (lower (?) to middle Pleistocene) - Moderately lithified,
crudely bedded pebble to boulder gravel in Gavilan Canyon. Approximately 45 meters
lower in elevation than QTg deposits. Poorly exposed, but appears to have smaller,
more angular, and less weathered clasts than QTg. Postdates incision of modern
drainages and is correlative to stream gravel unit (Qg) in the Ruidoso and Ruidoso
Downs quadrangles to the south. Correlated by Moore et al (1988a) to the Palomas
gravel of the Tularosa basin. Thickness: 0 to 20 (?) meters.
QTg – Pediment gravel deposits (Pliocene (?) to lower Pleistocene) – Moderately
lithified, crudely bedded pebble to boulder gravel with reddish clayey sand matrix and
local lenses of sand and sandy clay. Largest boulders are 80 cm in diameter. Clasts are
> 90 % Sierra Blanca volcanic rocks and associated intrusive igneous rocks. Clasts on
surface of deposit are heavily weathered and fractured. Surface is partly stripped.
Contains stage III to III+ carbonate soil near surface and local strong carbonate
buildup (equivalent to stage IV carbonate soil development) at base of unit. Roadcuts
in the Sonterra Ranch area expose irregular blebs and lenses of subsurface carbonate
cementation, possibly deposited by groundwater. Extensive downslope colluvium
makes base of unit hard to define where not exposed in roadcuts. Caps hills and broad
flat mesas in the eastern third of the quadrangle. Base of deposit slopes east at > 100
feet per mile. Deposited by steep gradient streams draining the Sierra Blanca,
predating incision of modern drainages. Thickness: 0 to 30 (?) meters.
Cenozoic Igneous Rocks
Tbs – Bonito Stock (upper Oligocene, 26.6 Ma) – Light purple to gray porphyriticphaneritic syenite. Rock is dominantly potassium feldspar with 10 to 15 %
hornblende and biotite and < 5% quartz. Propylitic alteration of mafic minerals to
chlorite and epidote is common. Intrusive contact in Mineral Farms Canyon exhibits
dikelets and apophyses of purple syenite with aphanitic cooling rind in dark grey
aphanitic andesite of Tdsc. Extensive bleaching and silicification due to hydrothermal
alteration is common along northern margin with Tsv. Remainder of margin is often
marked by a variably bleached and iron-stained border facies of grayish-lavender
aphanitic-porphyritic or very fine-grained phaneritic porphyritic syenite. Southwest of
Villa Madonna the syenite grades into greenish gray monzonite with more plagioclase
than potassium feldspar and extensive alteration of mafic minerals to chlorite. (Age is
K-Ar from Thompson, 1972). Thickness: Base and top not exposed; 1200 meters (?).
Km
QTg
Tbs
6
10
Km
Tad
3696000
Qvf
Km
12
11
Qbt1 – Upper terrace deposit of Rio Bonito (upper Pleistocene) - Poorly sorted alluvial
deposits composed of interstratified fine to coarse tan sand and sandy gravel of
rounded cobbles and boulders. Clasts are dominantly Bonito Stock (Tbs) and mixed
volcanic and intrusive igneous rocks. Deposit forms a terrace whose tread is generally
dissected and is at least 5 - 6 meters above present stream grade. Grades into and/or is
locally overlapped by hillslope colluvium. Largely mapped from aerial photographs.
Thickness: 0 to 6 (?) meters.
Qet2 – Lower terrace deposit of Eagle Creek (Holocene) – Poorly sorted alluvial
deposits composed of interstratified fine to coarse tan sand and sandy cobble to
boulder gravel. Deposit forms a terrace whose tread is generally preserved and is
within a meter of present stream grade. Largely mapped from aerial photographs.
Thickness: 0 to 3 meters.
11
10
17
65
38
86
Tm 21
24
87
Tbs
Tad
46
14
Tm
Qbt1
Qbt1
3702 000
75
10
Qbt1
Qbt2
Qaf
Qaf
28
af Qaf
15
12
Qaf
Qbt2 – Lower terrace deposit of Rio Bonito (Holocene) – Poorly sorted alluvial
deposits composed of interstratified fine to coarse tan sand and sandy cobble to
boulder gravel. Clasts are dominantly Bonito Stock (Tbs) and mixed volcanic and
intrusive igneous rocks. Deposit forms a terrace whose tread is generally preserved
and is within a few meters of present stream grade. Largely mapped from aerial
photographs. Thickness: 0 to 3 meters.
Qbt1
74
68
Tcm
Qbt2
22
33
15
27
Tcm
33°27'30"N
Qaf
QTg
85
17
Tsv
Qbt2
Tad
Kmv
68
16
18
Qvf
Tcm
15
86
47
17
85
58
Qbt2
15
22
15
27
9
Qbt2
Qvf
8
33
Qaf Qbt2 Qaf
Kmv
64
21
Qbt2
3701000
Kmv
6
66
14
Tad
14
Kmv
Qvf
12
88
15
Kmv
Tad
15
Tad
24
5
2
88
86
Tad
4
Tcm
73
af
Qbt2
Tad
44
Tad
64
Tm
Kmv
Tm
Tm
Qaf – Alluvial fan deposits (middle to upper Pleistocene) – Alluvial fans composed of
poorly sorted cobbles, boulders, sand, silt, and clay. Fans head in short, steep tributary
canyons and interfinger with and/or spread out onto Qvf and terrace deposits.
Stabilized by vegetation and apparently no longer active, and locally incised by
drainages floored with QHa. Only mapped along major drainages where geomorphic
expression is clear on aerial photos. Thickness: 0 to 8 (?) meters.
85
Qvf
Tcd
85
Qvf - Valley fill (upper Pleistocene to Holocene) - Unlithified valley fill composed of
poorly sorted clay, silt, and sand, commonly with angular to subrounded cobbles of
local bedrock. Matrix material is light to dark brown. Grades into minor alluvial and
colluvial fans on toes of hillslopes. Anthropogenic disturbance common in developed
areas. Generally incised by active drainages, floored by sand and cobble to boulder
gravel of QHa. Thickness: 0 to 12 (?) meters
Kmv
13
84
3703 000
Kmv
Qvf
Qvf af
18
QHa
Tad
Tcm
Qvf
24
Tad
Qvf
Kmv
32
76
Tcd
49
35
Kmv
Kmv
QTg
QTg
Kmv
Qvf
Tad
Qvf
QTg
af
74
3704 000
QHa
Tcm
85
58
33°27'30"N
Qvf
QHa
18
77
64
3705 000
QTg
Tad
Tad
Qvf
Tcm
70
Tad Tad
5
Tcd
Tcd
12 22
Tm
10
Tad Kmv
Qvf
Tad
3704000
79
13
Qvf
af
QHa - Alluvium (Holocene to Historic) – Unlithified gravel and poorly to moderately
sorted clay, silt, sand in active stream channels and ephemeral arroyos. Generally
incised into Qvf and terrace deposits. Only mapped where extensive; unit is otherwise
lumped with Qvf. Thickness: 0 to 4 (?) meters.
Tcm
32
40
Tad
Tcd
Tad
84
64
25
Tbs
Qvf
90
44
Tm
55
24 35
3706 000
Quaternary and Tertiary Surficial Deposits
Tcm
74
24
81
Kmv
Kmv
af
Qvf
Qvf
Kmv
Qvf
Qvf
daf Heavily disturbed land and artificial fill. Mapped where extensive, underlying
deposits are obscured, and/or geomorphic surfaces are extensively altered.
QHa Qvf
Tsv
30
Tad
af Artificial fill for stock tanks and highway embankments.
Kmv
QHa
QHa
Qvf
Tm
Tad
Tm
44
Kmv
Tsv
Qvf
56
30
77
Anthropogenic Deposits
Qvf
Qvf
Qvf
33°30'0"N
Tsv
QHa af
75
47
Qvf
af
Qvf
Qvf
Tm
Tm
Qvf
Tad
Tad
21
EXPLANATION OF MAP UNITS
32
36
A geologic map displays information on the distribution, nature, orientation, and age relationships
of rock and deposits and the occurrence of structural features. Geologic and fault contacts are
irregular surfaces that form boundaries between different types or ages of units. Data depicted
on this geologic quadrangle map may be based on any of the following: reconnaissance field
geologic mapping, compilation of published and unpublished work, and photogeologic interpretation.
Locations of contacts are not surveyed, but are plotted by interpretation of the position of a given
contact onto a topographic base map; therefore, the accuracy of contact locations depends on the
scale of mapping and the interpretation of the geologist(s). Any enlargement of this map could cause
misunderstanding in the detail of mapping and may result in erroneous interpretations. Site-specific
conditions should be verified by detailed surface mapping or subsurface exploration. Topographic
and cultural changes associated with recent development may not be shown.
Cross sections are constructed based upon the interpretations of the author made from geologic
mapping, and available geophysical, and subsurface (drillhole) data. Cross-sections should be used as
an aid to understanding the general geologic framework of the map area, and not be the sole source
of information for use in locating or designing wells, buildings, roads, or other man-made structures.
The map has not been reviewed according to New Mexico Bureau of Geology and Mineral Resources
standards. The contents of the report and map should not be considered final and complete until
reviewed and published by the New Mexico Bureau of Geology and Mineral Resources. The views and
conclusions contained in this document are those of the authors and should not be interpreted as
necessarily representing the official policies, either expressed or implied, of the State of New Mexico, or
the U.S. Government.
NMBGMR Open-file Map Series
OFGM 95
Last Modified 24 April 2006
OF-GM-95
Tad – Andesite/diorite dike, undivided (Oligocene) - Aphanitic to very fine-grained
phaneritic or phaneritic-porphyritic dike rocks. Generally dark gray on fresh surface
and brown to black on weathered surfaces. When phaneritic, often has a "salt and
pepper" appearance due to fine-grained equigranular white feldspar and black to
brown augite (?). Phenocrysts include augite, hornblende, and tabular intermediate (?)
plagioclase. Tabular plagioclase phenocrysts are up to 4 cm in diameter and are
usually aligned with the dike margins. Thickness: dikes are < 1 up to 5 meters
wide.
Kd – Dakota Sandstone (lower to middle Cretaceous) – Gray to tan to purple
sandstone and minor black shale. Sandstone is medium- to thick-bedded, trough to
tabular cross-bedded, ripple-marked, and composed of subangular to subrounded
vitreous quartz grains. Orange to rusty red liesegang bands are common on bedding
planes and fracture surfaces. Sandstone is more resistant, forms more prominent
outcrops, and weathers into more angular fragments than overlying Mesa Verde
sandstones. Matrix-supported sandy chert pebble conglomerate is present as a 1
meter thick layer at the base of unit and as sparse lenses throughout the unit. Thin
discontinuous beds of black shale similar to the overlying Mancos Shale are
sparsely distributed throughout the upper portions of the unit. Thickness: ~ 105
meters.
Tm – Monzonite (?) dike (Oligocene) – Tan to brown aphanitic to very fine-grained
phaneritic dike rocks. Typically composed of approximately equal amounts of
white feldspar and tan to brown mafic minerals with little or no quartz. Often
weathers in a granular fashion resulting in a surface texture resembling sandstone.
Feldspar is largely intermediate (?) plagioclase with lesser amounts of potassium
feldspar and forms a felted network of interlocking crystals. Includes rocks
ranging from syenite to diorite in composition. Thickness: dikes are < 1 up to 5
meters wide.
Tcd – Diorite of Champ Hill (Oligocene) - Dark gray to grayish-brown fine-grained
phaneritic diorite with 10-15% phenocrysts of augite. Forms an irregular pluton
underlying Champ Hill and much of the surrounding area east of NM 48 in the
northeast corner of the quadrangle. Subcrop and float of this rock and similar
rocks with more or fewer phenocrysts of augite and plagioclase and variable
phenocryst size cover a large area with inliers or xenoliths of Mesa Verde
sandstone. Probably a stock (forming Champ Hill) and associated dikes and sills.
Float of similar rocks from dikes and sills is common in the northern half of the
quadrangle. Thickness: Base and top not exposed; sill shown in cross section A-A’
190 meters.
@sr - Santa Rosa Formation (upper Triassic) - Dark brownish-red fine-grained
sandstone, siltstone, and dark red mudstone. Reduction spots are common in the
sandstone and siltstone. Base of the unit is marked by a gray to orange to red
medium- to thick-bedded quartzite and chert pebble conglomerate with a matrix of
coarse chert-rich sand. Conglomerate is scoured into underlying Grayburg
Formation. Very poorly exposed and usually mantled by collivium from overlying
Dakota Formation. Thickness: 33 to 45 meters.
Paleozoic Sedimentary Rocks
Pg – Grayburg Formation (upper Permian) - Gray, tan, and yellowish-brown finegrained sandstone and siltstone and minor gypsum. Sandstones and siltstones are
very thin- to thick-bedded, parallel to crossbedded, and composed of quartz. Very
poorly exposed. Thickness: ~ 350 meters.
Tsv – Sierra Blanca volcanic rocks, undivided (upper Eocene to Oligocene) –
Walker andesite breccia of Thompson (1972). Interbedded dark purple, purplishred, red, and light to dark gray and gray –green volcanic flow breccias, volcanic
debris flows, shallow intrusive sills, lahars, and volcaniclastic sedimentary rocks
from the Sierra Blanca volcanic center to the west of the quadrangle. Rocks are
generally alkalic and range from mafic (tephrite, phonotephrite, trachybasalt) to
intermediate (andesite and latite) to felsic (rhyolite, trachyte, phonolite) in
composition. Flow breccias are dominant and consist of varicolored angular to
subrounded clasts of volcanic and lesser intrusive rocks in a purple or purplishgray fine-grained matrix. Matrix is often propylitically altered. Clast population
may be monolithologic or varied. Outcrops are massive to crudely bedded and
individual flow units are generally 2 to 3 meters thick. Shallow intrusive sills are
light to dark gray and aphanitic. Lahar deposits and volcaniclastic sedimentary
rocks are red to purple muddy sandstones to conglomerates with variably
developed bedding and sorting. Sandstones are well bedded, often with finingupward graded beds less than 0.5 cm thick. Natural exposures of all units are poor
and individual units are not laterally traceable. Not subdivided except in areas
compiled from Moore et al (1988b, see below). Good exposures are in roadcuts
on NM 532 and display interbedded volcanic and volcaniclastic units folded into
50 to 100 meter wavelength synclines and anticlines, probably due to faulting and
forcible intrusion of numerous dikes and sills. Thickness: 250 meters.
Tsv-tp – Trachyphonolite porphyry flows - Fine- to medium-grained medium to
dark-gray-green flows with plagioclase phenocrysts. Unit from Moore et al.
(1988b). Thickness: 25 meters.
Tsv-tf – Trachybasalt flows - Fine- to very fine-grained dark gray aphyric flows. Unit
from Moore et al. (1988b). Thickness: ~ 60 meters.
Td – Diorite (upper Eocene or Oligocene) – Shallow subvolcanic sill or nonvesicular flow concordant with over- and underlying Tsv flow breccias. Medium
to dark gray aphanitic to very fine-grained phaneritic matrix with 10 – 45%
plagioclase phenocrysts from <1 to 4 centimeters in length and 5 – 7% augite
phenocrysts generally less than 1 cm in length. Plagioclase phenocrysts are often
aligned horizontally or grouped in radial rosettes. Thickness: ~ 90 meters.
Tdsc – Dike and sill complex (upper Eocene to Oligocene) – Area northeast of the
Bonito Stock characterized by float of a wide variety of intermediate and felsic
igneous rocks including andesite, diorite, monzonite, and latite, but very sparse
outcrop. Appears to be > 90% igneous rocks. No outcrop or float of Bonito Stock,
or textures indicative of flow breccias, lava flows, or tuffs. Field relations suggest
that felsic rocks such as monzonite are more common as irregular, discordant
masses, whereas intermediate rocks such as diorite are more common as dikes and
sills. Isolated subcrop on hilltop west of Mills Canyon of white to tan quartz
sandstone is either Mesa Verde group sandstone or contact metamorphosed Cub
Mountain formation sandstone and is the only sedimentary rock observed in this
unit. Unit is probably a dike and sill complex. Roadcut at Bonito Store exhibits
several vertical andesite dikes intruded into gray aphanitic andesite sills or
nonvesicular flows (?). Contact with Tsv is gradational between Mills and Vickers
Canyons. Thickness: Base and top not exposed; 600 meters (?).
Mesozoic Sedimentary Rocks
Kmv – Cretaceous Mesa Verde Group, undivided (upper Cretaceous) – Lavender
to tan sandstone and conglomerate, olive to gray sandy siltstone and siltstone, and
dark gray, grayish-purple, and black shale. Sandstones are fine- to mediumgrained, medium- to very thick-bedded, trough cross-bedded, and composed of
subrounded to subangular grains. Dominantly quartose and resistant, but locally
arkosic and friable. Conglomerate is present as lenses within sandstone beds. Iron
concretions and plant fossils are common. Shales are carbonaceous and fissile and
usually interbedded with blocky weathering thin- to medium-bedded, occasionally
micaceous, siltstone and sandy siltstone layers with ripup clasts of black shale.
Subdivsions of the unit (e.g., Gallup Sandstone, Crevasse Canyon Formation) are
not mappable in the quadrangle. Unit is ubiquitously intruded by igneous dikes,
sills and irregular masses. Adjacent to these bodies shales are often contact
metamorphosed to low grade hornfelses and weather into gray angular chips
rather than black flakes. Thickness: ~ 240 meters.
Km – Mancos Shale (middle to upper Cretaceous) – Black to purplish-gray
laminated fissile shale. Ovoid calcareous concretions are locally abundant. Black
to dark gray to olive thin-bedded fine-grained sandstone and siltstone beds less
than 0.5 meters thick and thin- to medium-bedded limestones 1 - 2 meters thick
are minor constituents. The contact with the underlying Dakota sandstone is
transitional over at least a 50 foot interval, with thin medium-grained quartz
sandstone beds within black fissile shale. Igneous intrusions are common.
Thickness: ~ 335 meters.
Geology within Mescalero Tribal lands in the southwestern corner of the
quadrangle was compiled from Moore et al (1988b).
Doug Rappuhn of the New Mexico State Engineer’s Office kindly provided
lithologic logs of water wells in the Ruidoso area.
REFERENCES CITED AND SELECTED REFERENCES
PERTINENT TO THE STUDY AREA
Ash, S. R., and Davis, L. V., 1964, Guidebook of the Ruidoso Country: New Mexico
Geological Society, Guidebook 15, 189 p.
Barker, J. M., Kues, B. S., Austin, G. S., and Lucas, S. G., 1991, Geology of the Sierra
Blanca, Sacramento, and Capitan Ranges: New Mexico Geological Society,
Guidebook 42, 362 p.
Cather, S. M., 1991, Stratigraphy and provenance of Upper Cretaceous and Paleogene
strata of the western Sierra Balca Basin, New Mexico, in Barker, J. M., Kues,
B. S., Austin, G. S., and Lucas, S. G., eds., Geology of the Sierra Blanca,
Sacramento, and Capitan Ranges: New Mexico Geological Society, Guidebook
42, p. 265-275.
Kelley, V. C., 1971, Geology of the Pecos Country, Southeastern New Mexico: New
Mexico Bureau of Mines and Mineral Resources Memoir 24, 75 p.
Psa - San Andres Formation (middle to upper Permian) - Light to dark gray and
bluish-gray limestone and dolomite. Limestones and dolomites range from thin- to
very thick-bedded, and are carbonate mudstones, wackestones, and grainstones.
Freshly broken surfaces are darker gray than weathered surfaces and occasionally
fetid. Beds are often silty or sandy. Dark brown irregular chert nodules are sparse.
Fossils are sparse and are dominantly crinoid stem fragments. Intraformational
solution breccias and paleokarst features are common along faults and as isolated
occurrences, probably collapsed caves. They are characterized by red soil and red
and yellow breccia fragments. Contact with the overlying Grayburg Formation is
marked by development of reddish-yellow to buff solution breccia and abundant
vugs filled with calcite crystals. The base of the unit is characterized by irregular
bedding dips due to gypsum dissolution in the underlying Yeso Formation.
Delineation of the San Andres into the lower thick-bedded Rio Bonito Member and
upper thin-bedded Bonney Canyon member (Kelley, 1971) was attempted but was
not possible due to steep topography, heavy vegetation, and sparse outcrop. The
lowest portions of the unit do contain abundant thick beds, but in this area vertical
changes in bedding thickness and bed color are not mappable distinctions.
Thickness: ~ 335 meters.
Moore, S. L., Foord, E. E., and Meyer, G. A., 1988a, Geologic and aeromagnetic map of
a part of the Mescalero Apache Indian Reservation, Otero County, New
Mexico: U. S. Geological Survey Miscellaneous Investigations Series Map I1775, 1:50000 scale.
Py – Yeso Formation (middle Permian) - Sandstone, siltstone, carbonates, and gypsum
(cross section only). Thickness: 240 meters based on exposures in Ruidoso Downs
quadrangle to the southeast. Wasiolek (1991) reported a regional thickness range of
320 to 380 meters based on wells from the north central part of the Mescalero
Reservation.
Thompson, T. B., 1972, Sierra Blanca Igneous Complex, New Mexico: Geological
Society of America Bulletin, v. 83, p. 2341-2356.
P\u - Permian to Proterozoic rocks – Paleozoic sedimentary rocks and Proterozoic
igneous and metamorphic rocks, undivided (cross section only). Thickness of SubYeso Paleozoic rocks unknown.
MAP AND CROSS SECTION SYMBOLS
A
A Location of geologic cross section
?
Geologic contact, solid where exposed, dashed where approximately
located, dotted where concealed, queried where inferred
? Normal fault, arrow shows dip and dip direction of fault plane where
measured, ball and bar on downthrown side, dashed where
approximately located, dotted where concealed. Fault tip is
queried where the termination of fault is unknown.
Fault, relative motion unknown, dashed where approximately located,
dotted where concealed
Cenozoic Sedimentary Rocks
Tcm – Cub Mountain Formation (Eocene) – White to tan sandstones, dark red
sandy mudstones, and purplish-red silty mudstones. Sandstones are medium- to
thick- bedded, cross-bedded, medium-grained, and arkosic to volcaniclastic.
Pebble conglomerate lenses, mudballs, and ripup clasts of red mudstone, and
olive, black, and gray siltstone and shale are locally common. Sandstones are
generally more friable than underlying Cretaceous sandstones. Sandy and silty
mudstones are thick bedded to massive and micaceous. Several outcrops are
volcaniclastic in nature, and the unit thus includes the Sanders Canyon Formation
of Cather (1991), but the two formations are not mappable separately in the
quadrangle. Unit is ubiquitously intruded by igneous dikes, sills and irregular
masses. Thickness: 450 meters.
NOTES AND ACKOWLEDGEMENTS
Anticline, trace of axial plane showing plunge
Syncline, trace of axial plane showing plunge, dashed where
approximately located
20 . 295
Dip and dip direction of bedding
20 . 295
Dip and dip direction of joints
40 . 295
Dip and dip direction of plane of small fault
295 . 40
Trend and plunge of slickenside striae
5i
Paleocurrent direction, # i indicates number of imbricated gravel clasts
measured. Tail of arrow is at measurement point
80 . 295
Outcrop and local trace of dike, with dip and dip direction where
H00123
Water well with NM State Engineer Office W.A.T.E.R.S. database
measured
reference number
Water well projected into cross section
Moore, S. L., Foord, E. E., Meyer, G. A., and Smith, G. W., 1988b, Geologic Map of the
northwestern part of the Mescalero Apache Indian Reservation, Otero County,
New Mexico: U. S. Geological Survey Miscellaneous Investigations Series
Map I-1895, scale 1:24000.
Mourant, W. A., 1963, Water resources and geology of the Rio Hondo drainage basin,
Chaves, Lincoln, and Otero Counties, New Mexico: New Mexico Office of the
State Engineer Technical Report 28, 85 p.
Sloan, C. S., and Garber, M. S., 1971, Groundwater hydrology of the Mescalero Apache
Indian Reservation, south-central New Mexico: U.S. Geologic Survey
Hydrologic Investigations Atlas HA-349, scale 1:125000.
Thompson, T. B., 1966, Geology of the Sierra Blanca, Lincoln and Otero Counties, New
Mexico: PhD Dissertation, University of New Mexico, 146 p.
Wasiolek, M., 1991, The hydrogeology of the Permian Yeso formation within the upper
Rio Hondo Basin and the Eastern Mescalero Apache Indian Reservation,
Lincoln and Otero Counties, New Mexico, in Barker, J. M., Kues, B. S., Austin,
G. S., and Lucas, S. G., eds., Geology of the Sierra Blanca, Sacramento, and
Capitan Ranges: New Mexico Geological Society, Guidebook 42, p. 343-351.