NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES
A DIVISION OF NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY
355000
356000
35°45'0"N
Qls Qbo
3957000
Qbo Qbo
Tbr
Tpbhd
Tpbhd
Tbr
Tpbhd
Tpa
Tpa
Tpa
Tpa
Qbt
Qc
Qbt
Qal
Qec
Qbo
Qc
3955000
Qec
Qbt
Qal
Tpb
Qec
Tpb
Qbt@c
Qbt
Tpb
@c
5 Qbt
@c
Tpb
Tpd
Qec
Tpb Qec
Qec
Qec
Tpb
Tpb Tpv
@c
Tpv
Tpb
Qls
Qec
Tpb
Tpd
Tpd
@c
Qc
TpvTpv
Tpd
Qtal
3953000
Qt
35°42'30"N
Tpb
Tpv
Tpv
Tpa
QbtTpa
Tpa
Qec
Qec
Tpv
Tpa
Qls
Qec
Qal
Qc
Tbr
11
Tpb
Qec Qec
Tpb
Qec
Qec
Qec
Tpv
Tpb
Tpa
Tpa
Tct 16
Tcc14
TpbiTpbi
Tpa
Tcc
Qt
Tct
Tcc
Tct
Qc
Qc
Qec
Tpa
Tpd
Qt
Tcc
Tsf?
Tsf?
Qal
Qec
Qal
3948000
35°40'0"N
Tpb
Tpbd
Tpbd
Tct
Qal
Tpbd
Qec
Qec
Tpbd
Qt
Qec
Tcc
Tct
Tct
Tcc
Tcc
Qec
Tpv
Tpv
Qal
Tcc
Qec
Qec
Tct
Qec
Tct
Qc
9
Tct
Qec
Qec
Qec
Qal
Qal
Tct
Tpb
Tpb Tpv
Tpv
Tcc
43
Qec
Qe
Qec
Qal
Tpv
Tpbd
Tpbd
Qal
Qc
Qc
Tbp Tpbd
Qec
Tbr
Tct
Tbp
Tpv
Qc/QalQc/Qal
Tbp
Qal
Tpv
Tpa
Tpbd
Qc
Qc
TpdTpa
Tpv
Tpv
Tpbbs
Tpbbs 20
Qal
Tpmc
Tpv
Tpv
Qc Tcct
Tcct
Tcc
Qal
11
Tpv Tpv
Tpv
Qec
Tpbbs
Tcc
Tcc
Tpv
Tpbd
Qc
Qt
Tpv
Qal
TpbdTpv
Qec Tglp
Qal
Tct
Qe
Tct
Qc
Tct
Tcc
Tpbd
Tcc
Tpv
Tpv
Tc
Tcc
Tpcm Tscc
Tpv
Qc
Tcc
Tc
Tcc
Tc
Tpb/
Tpbs
Tc
Tc
Tcc
Qtal
Tbp
Tpa Tpbb?
Tpmc
Qal
Tct
Qal
Tbp
Tglp
Qe
Tc
Tc
Tbp
35°37'30"N
3943000
Tpbt
Hydromagmatic tephra associated with basalt of the Paliza Canyon Fomation (Miocene).
Tpv
Tpa
Tpbb
Tpd
Tpb
Tpbi
Basaltic dikes associated with basalt of the Paliza Canyon Formation (Miocene).
353000
354000
355000
356000
357000
358000
359000
360000
106°35'0"W
361000
Base map from U.S. Geological Survey1984 from photographs taken 1976, field checked in 1976, edited in 1984.
1927 North American datum, UTM projection -- zone 13N
1000-meter Universal Transverse Mercator grid, zone 13, shown in red
1:24,000
JEMEZ
SPRINGS
REDONDO
PEAK
1
BLAND
362000
363000
364000
106°32'30"W
0.5
0
1 MILE
Preliminary geologic map of the Bear Springs
Peak quadrangle, Sandoval County, New Mexico.
June 2007
NEW MEXICO
PONDEROSA
JEMEZ
PUEBLO
BEAR
BEAR
SPRINGS
SPRINGS
PEAK
PEAK
LOMA
CRESTON
1000
0
1000
2000
3000
4000
5000
6000
7000 FEET
1
SANTO
DOMINGO
PUEBLO SW
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
by
Kirt Kempter , G. Robert Osburn 2, Shari Kelley 3,
Michael Rampey 4, Charles Ferguson5, and Jamie Gardner 6.
1
CANADA
Magnetic Declination
May, 2002
10º 16' East
At Map Center
0.5
0
1 KILOMETER
CONTOUR INTERVAL 40 FEET
NATIONAL GEODETIC VERTICAL DATUM OF 1929
New Mexico Bureau of Geology and Mineral Resources
Open-file Geologic Map 74
Tpcm
Basalt of Chamisa Mesa, Paliza Canyon Formation. (Miocene) - Dark gray to black, fine-grained aphyric to phenocryst-poor basalt
with rare crystals of olivine. Chamberlin and McIntosh (2007) determined a 40Ar/39Ar age of 9.9 ± 0.9 Ma on two samples on the Loma
Creston quadrangle.
Tscc
Cerro Conejos Formation, Santa Fe Group (Miocene) - Red to tan sandstone with rounded quartz grains that is moderately- to wellsorted that is interbedded with Canovas Canyon Rhyolite tuffs. These sandstones are included in Tcct. This unit is also below the
basalt of Chamisa Mesa.
106°30'0"W
Tku
Undivided Keres Group volcanic rocks (Miocene). (on cross-section A-A’) .
TRc
Undivided Chinle Group (Triassic) (on cross-section A-A’)
TRcs
Shinarump Formation. Chinle Group (Triassic) (on cross-section A-A’) .
Tru
Undivided upper part of Chinle Group (Triassic) (on cross-section A-A’) .
Pu
Undivided Permian sedimentary rocks (on cross-section A-A’) .
Tpbi
Tpbs
Tcr
Tct
Tscc
Tpcm
@c
@u
@cs
Pu
REFERENCES
Comments to Map Users
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.
Chamberlin, R.M., and McIntosh, W.C., 2007, Chronology and structural control of Late Cenozoic volcanism in the Loma Creston quadrangle,
southern Jemez volcanic field, New Mexico: New Mexico Geological Society Guidebook 58, in press.
Chamberlin, R. M., Pazzaglia, F. J., Wegmann, and Smith, G. A., 1999, Preliminary geologic map of Loma Creston quadrangle, Sandoval
County, New Mexico: New Mexico Bureau of Geology and Mineral Resources Open file report OF-GM-25, scale 1:24,000.
Gardner, J. N., 1985, Tectonic and petrologic evolution of the Keres Group: Implications for the development of the Jemez volcanic field, New
Mexico: Ph.D. dissertation, University of California at Davis, 172 pp.
Gardner, J. N., Goff, E, Garcia, S., and Hagan, R. C., 1986, Stratigraphic relations and lithologic variations in the Jemez volcanic field, New
Mexico: Journal of Geophysical Research, v. 91, p. 1763-1778.
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.
Guilbeau, K. P., 1982, Geology, geochemistry, and petrogenesis of the Upper Keres Group, Ruiz Peak area, Jemez Mountains, New Mexico:
M.S. thesis, University of New Mexico, Albuquerque, 132 pp.
Guilbeau, K. P.; Kudo, A. M., 1985, Petrology and geochemistry of the Paliza Canyon Formation and the Bearhead Rhyolite, Keres Group,
Jemez Mountains, New Mexico: Geological Society of America Bulletin, v. 96, p. 108-113
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.
Justet, L. and Spell, T. L., 2001, Effusive eruptions from a large silicic magma chamber: The Bearhead Rhyolite, Jemez volcanic field, N.M.:
Journal of Volcanology and Geothermal Research, v. 107, p. 241-264.
Reneau, S. L., Gardner, J. N. and Forman, S .L., 1996, New evidence for the age of the youngest eruptions in the Valles caldera, New Mexico:
Geology, v. 24, p. 7-10.
Explanation of Map Symbols
Explanation of Map Symbols
Smith, R. L., Bailey, R. A., and Ross, C. S., 1970, Geologic map of the Jemez Mountains, New Mexico: U.S. Geological Survey Miscellaneous
Investigation Series Map I-571, scale 1:125,000.
A
Spell, T. L., McDougall, I. and Doulgeris, A. P., 1996, The Cerro Toledo Rhyolite, Jemez Volcanic Field, New Mexico: 40Ar/39Ar
geochronology of eruptions between two caldera-forming events: Geological Society America Bulletin, v. 108, p. 1549-1566.
A'
?
?
3943000
106°37'30"W
Tpbbs
Tpbt
Justet, L., 1996, The geochronology and geochemistry of the Bearhead Rhyolite, Jemez volcanic field, New Mexico: M.S. thesis, University of
Nevada, Las Vegas, 152 pp.
Tcc/Tct Canovas Canyon Rhyolite lavas (Tcc) and associated pyroclastic and alluvial deposits (Tcct) (Miocene) — Mostly beige to
pinkish-gray, flow-banded, phenocryst-poor lavas. Dark grey to green obsidian facies common in more voluminous flows. Phenocrysts
are typically small (< 2 mm) and include biotite, sanidine, and rare quartz. West of the Cocida fault zone pyroclastic deposits are
intercalated with sandstones, tuff breccia, and tephra deposits. The largest contiguous flow occurs east of Bear Springs Peak and covers
an area of > 6 km2. Although the thickness of this unit is unknown (the base of the flow is not exposed), the flow is widespread and
appears to have a relatively low-aspect ratio more typical of lavas with a lower silica content. A similarly widespread pyroclastic flow
overlies the lava and in several locations the two units appear to be intimately associated with one another, suggesting a continuum in
the eruption process. Other rhyolite lavas of this unit are of limited lateral distribution (< 1 km2) and exhibit a more typical high-aspect
ratio morphology. Most of the Canovas Canyon rhyolites were erupted along N-S-trending faults active during the mid-Miocene.
40
Ar/39Ar dates for biotite from flows at 0361786 3948981 and 357602 3946081 are 8.81±0.16 Ma and 9.75±0.08 Ma, respectively.
Maximum thickness exceeds 150 m.
3944000
Qec
Basalt, Paliza Canyon Formation (Miocene) — Medium to dark gray lavas and associated scoria deposits (Tpbs).
Poorly to moderately porphyritic with phenocrysts of plagioclase and pyroxene. Trace amounts of olivine and/or hornblende may be
present. Flows are typically flow banded and platey. Brecciated basal and top horizons of flows and vesicular horizons are also
common. Most of the flows are intercalated with gravel deposits (Tpv) and appear to have originated along N-S structures related to the
western Cocido fault zone, flowing to the southeast. An 40Ar/39Ar date for a flow from the base of this unit is 9.54±0.08 Ma. Maximum
thickness of individual flows can exceed 30 m.
Qal
Qal
Tbb
Tcc Qc/Tc
Basalt of Bodega Butte, Paliza Canyon Formation (Miocene) - Dark gray olivine basalt that is massive to vesicular and moderately
porphyritic with phenocrysts of plagioclase, olivine and pyroxene. Phenocryst content is typically < 10% with olivine commonly altered
to reddish-brown iddingsite. Weathered surfaces on the basalt are covered with distinctive reddish speckles. Basalt breccias and
vesicular horizons are common. This widespread unit in the southeast portion of the quadrangle appears to have been emplaced during
one eruptive episode, although separate flows may have overlapped. An 40Ar/39Ar date for this unit from a sample collected at the
confluence of Hondo and West Fork Canyons is 9.10±0.13 Ma. Chamberlin and McIntosh (2007) determined an average age of
9.14±0.12 Ma from four samples on the Loma Creston quadrangle to the south. Maximum thickness of unit exceeds 30 meters.
Tpbbs Scoria facies of basalt of Bodega Butte. Paliza Canyon Formation. Miocene.
Qec
Qt
Tpv Qal
Qal
Qc
Tc
Qc
Tpv
Qe
Tpv
Tc
Tbp
Tct
Tpb
4
3946000
Qc/Qal
Tct
Tpv
Tpv
Tpbb
3945000
Tbp
50 65
Tpv
Qc
Tbp
Tcc
Qe
Tpbb
Tc
Tbp
Tpmc Tpmc
Qal
Qe
Qec
Dacite, Paliza Canyon Formation (Miocene) — Light to dark gray porphyritic lavas with phenocrysts of plagioclase, hornblende, and
biotite. Some lavas also contain small amounts of quartz and pyroxene. Flows are typically massive but can also exhibit flow banding
and brecciated horizons. An older sequence of dacites, exposed along Forest Road 266 between Bear Springs Peak and Cerrito Yelo, is
stratigraphically below most of the thick andesite package to the north. The andesite package is then capped by a younger dacitic
sequence of lavas and domes. These dacitic lavas, including dome complexes at Cerro Ruiz and north of Paliza Canyon, tend to be
more coarsely porphyritic, with phenocrysts of plagioclase (up to 1 cm across), pyroxene, and rare hornblende or biotite. Maximum
thickness of this unit exceeds 150 m.
Qe
Qc
Qc
Tpbd
35°37'30"N
Tc
Tbp
Qc
Tpd
Tglp
Qec
QalQec
Tpmc
Andesite, Paliza Canyon Formation (Miocene) — Typically medium gray to reddish purple porphyritic lavas and associated
pyroclastic deposits. Phenocryst content is typically <20% and includes acicular plagioclase with less abundant pyroxenes
(clinopyroxene and/or orthopyroxene). Flow banding is common, as are vesicular and brecciated horizons. Debris flow deposits,
typically less than 5 meters in thickness, occur intercalated with lava flows. A thick package of these andesitic units occurs north and
east of Tres Cerros, suggesting a source in this vicinity. One distinctive flow, dark gray and very fine-grained with sparse phenocrysts
of plagioclase and pyroxene, occurs in numerous outcrops peripheral to Cerrito Yelo. This unit is offset by several faults that radiate
from the Cerro Yelo center and is overlain by the Peralta Tuff Member of the Bearhead Rhyolite. An 40Ar/39Ar date for a flow near the
top of this unit at Tres Cerros is 10.8 ± 1.5 Ma on hornblende. Maximum thickness of this unit exceeds 200 m.
Qe
Qal
Ql
Tbp
Tbp
Qe
Qal
Tpa
3947000
Tbp
Qc/Qtal
Tpbd
Tct
35°40'0"N
Qal
Qec
Qec
Tct
Qt
48
Tcc
3944000
Qec
Tglp
Tbp
Qc
Tct
Tpai
Tpdb
Trachyandesite of Mesita Cocida, Paliza Canyon Formation (Miocene) - Medium to dark gray diktytaxitic lavas, poorly to
moderately porphyritic with rare phenocrysts of plagioclase, pyroxene and trace amounts of olivine and hornblende. The weathered
outcrop is platy in appearance. Massive, flow banded, and vesicular horizons are common. Chamberlin and McIntosh (2007)
determined an age of 7.09±0.21 Ma for this unit based on three samples on Mesita Cocida on the Loma Creston quadrangle. Maximum
thickness exceeds 20 meters.
Biotite-bearing rhyodacite, Paliza Canyon Formation (Miocene) — Light to dark gray porphyritic lavas with phenocrysts of
plagioclase and biotite.
Qec
Qec
Tpa
TccQec
Qec
Tbp
Bearhead Rhyolite (Upper Miocene) — Light gray to white rhyolite lavas and associated pyroclastic deposits, typically crystal-poor,
with sparse phenocrysts of quartz, sanidine and biotite. Lavas typically high-aspect ratio and erupted along N-S-trending or NE-SWtrending structures. Some rhyolites of this unit, including two domes just north and west of Tres Cerros, are moderately crystal rich,
with abundant quartz and sanidine phenocrysts and lesser amounts of biotite. Most of the lavas from this episode of volcanism occur in
the southeast portion of the quadrangle, possibly related to a batholithic magma chamber emplaced at approximately 6.8 Ma. The most
voluminous and contiguous outcrops of this unit are exposed in Peralta Canyon, where hydrothermal alteration is locally pervasive. A
rhyolite lava located east of Tres Cerros (0361690 3950778) has an 40Ar/39Ar date of 6.86 ± 0.28 Ma on sanidine and a rhyolite lava
north of Paliza Canyon has an 40Ar/39Ar age of 6.66±0.61 Ma on biotite. Maximum thickness exceeds 150 m.
Tpdb
Qt
Qtal
Tct
Tct
Tbr
Peralta Tuff Member of the Bearhead Rhyolite (Upper Miocene) — Lithic-rich tuffs and minor tuff breccias. Typically white to
beige, poorly-welded with sparse phenocrysts of quartz, biotite, plagioclase, and quartz. The most voluminous and widespread tuff of
this unit occurs along the footwall of the Yelo fault, extending to the NE towards Bear Peak on the Cañada quadrangle. Pumice from
the tuff of Cerrito Yelo on the Cañada quadrangle is 6.29 ± 0.08 Ma. At Cerrito Yelo this tuff is overlain by a younger, phenocryst-rich
rhyolite lava. Preliminary correlation of this tuff on the west side of the Yelo fault is stratigraphically above dacite lavas in the vicinity
of Ruiz Peak and intercalated with andesite flows on the east side of Tres Cerros. Exposures of this tuff east of Ruiz Peak are strongly
bedded with large (> 1 m) and abundant lithics, suggesting a nearby source. Maximum thickness of this unit exceeds 70 m.
Volcaniclastic deposits. Paliza Canyon Formation (Miocene) - Volcaniclastic conglomerates, sandstones and silts of mixed
provenance. Older sediments of this unit are primarily intercalated with thin basalt flows of the Paliza Canyon Formation and tephras
of the Canovas Canyon Rhyolite, whereas the younger gravels are intercalated with andesite and dacite lavas. These gravels thicken to
the southwest towards Borrego Mesa and exhibit southeast-trending imbrication. Maximum thickness is approximately 100 meters.
Qec
Qec
Qt
Tc
Cochiti Formation, Santa Fe Group (Miocene to Pliocene) — Volcaniclastic sediments with pebble to cobble sized clasts derived
primarily from Paliza Canyon, Canovas Canyon, and Bearhead rhyolite units in the study area. This unit includes conglomeratic
sandstones interbedded with fine-grained sands and silts, covering much of the southern and southeastern portion of the quadrangle.
Maximum thickness is approximately 100 m.
Tpv
Tbp
Tprd
Tct
Tpv
Tcc
Qc
Tpbd
Qc
Tbp Qc
Qec
Tpbd Qec
Tct
Tct
Tct
Tglp
Gravel of Lookout Park (Pliocene) — Stratified cobble to boulder gravel almost entirely derived from upper Miocene volcanic strata.
Relative proportions of basalt, basaltic andesite, andesite, dacite and rhyolite clasts vary with the bedrock lithology of the local
provenance. The Gravel of Lookout Park, as mapped in the Loma Creston quadrangle to the south of the map area, is both slightly older
than and slightly younger than the upper Pliocene basalts (ca. 2.5 Ma) that cap Santa Ana Mesa.
Andesite dikes that may be the source of the trachyandesite of Mesita Cocida, Paliza Canyon Formation (Miocene).
3948000
Qc
Tcc
Tpbd
Qal
Tpv
Qe
Qal
Tbp
Tbp
Tpv
Qc
Qbt
Tpmc
Tpai
Qec
Tbr
Qc
3945000
Tbp
Qtal
Tcc
Qec
Qt
Tct
Tcc
Tbp
Tpa
Qal
Qc/Qt
Tpai
Qec
Tct
Tct
Qal
Qec
Qec
Qt
Tct Tct
Qal
Qt
Qt
Tpa
Qec
Tct
Tct
Tpai
Qec
Qt
Qt
Tcc
Tct
Tpbd
Qt
Tct
Tct
Tpbd
Qls
Qbo
3949000
Qec
Qec
Tpa
Tpbd
34
Qe
Qe
Qal
Qc
Qt
Qec
Tpb
Qal
Qec
Tct
Tct
Tpd
12
Tpd
Tct
Qt
Tpbd
TpbdQec
Qt
Qec
Qec
Tpa
Qec Tprd
Tcc Tcc
32
25
40
Qt
Tpd
Tpd
Tpv
Qt
Qt
Qt
60
Tc
Tpmc
Tpa
Tct
Qal
16
18
Tcc
Tcc
Tpbd
Tpbd
Tpbd
Tpbd
Tpa
Qec
Tpa
Tpmc
Qec
Qec
Tcc
3950000
Tpa
Qt
Qec
Tbr
Qal
Tpd
Qtal
Qec
Tct
Tcc
Tct
TpbdTpbd
Tbp
Tbr
Qc
Tcc
Tcc
Tpv
Tpbd
3946000
Tct
Tcc
15
9
Tbr
Tbr
Qc
Tpd
Qec
Qec
22Qec
Tprd
Tprd
Tbp Tpa
Qal
12
Tct
Tpbd
Qec
Tct
Tct
Qec
Qec
Tpbd
Qec
Qt
Tbr
Qc
Qal
Tpbd
Tbr
Qec
Qt
Tpbd
Tpbi
Tpbd
Tpv
3947000
Tct
Tpd
17
Tpv
Tsf?
Tpb
Tpa
Qec
Qal
Qec
Tct
Qtal
Qec
Qal
Qec
Qec
Qec
Tpbd
Tct
Qal
Qec
Qec
2153
Qec
Tbp
Tct
Tpv
Tpbd
Tpbd
Tpv TpbdTpv
Tpbd
3951000
Tcc
Qt
Qec
Tsf?
Tpd
Qal
Qec
Tpv
Tpbd
Qec
Tbp
Qc
Tpa
Tcc
Tpv
Tpb
Tct
Qtal
Tca
Tpa
Tpb
Tpv
Qbo
Tct
Tct
Tpb
Qbt
Tct
Qc
TpbTpv
Tpb
Tglp
Tbr Tbp
Tpd
Qe
Tertiary
Tglp
Tpb
Qec
Tpb
Lower Bandelier Tuff (Otowi Member) (Lower Pleistocene) — White to beige non-welded ash-flow tuff containing abundant
phenocrysts of quartz and sanidine and sparse mafic phenocrysts. Moderate to abundant lithic fragments, primarily of andesitic or
mafic lavas. This unit is best exposed in the northwest corner of the quadrangle where it filled a large paleocanyon, later reincised to
form the modern San Juan Canyon. Isolated exposures also occur in Peralta Canyon where capped (preserved) by the Tshirege
Member. Erupted at approximately 1.61 Ma during the formation of the Toledo caldera. Maximum thickness is approximately 70 m.
Tpd
Qal
Qec
Qec
Qec
Qal
Qbo
3952000
Qtal
Tcc
Qec
Tpb
Qec
Upper Bandelier Tuff (Tshirege Member) (Lower Pleistocene) — White to beige non-welded to welded ash-flow tuff containing
abundant phenocrysts of quartz and sanidine. Exposed primarily in the northwest corner of the quadrangle and as isolated outcrops in
Paliza and Peralta canyons. Basal Tsankawi pumice only recognized in exposures along San Juan Canyon, overlain by multiple (≥ 3)
flow units. Erupted at approximately 1.22 Ma during the formation of the Valles caldera. Maximum thickness is approximately 170 m.
Qbo
Tbr
Qc
Tct
Tpv
Tcc
Tpa
Tpb
Qal
35°42'30"N
Tpd
Tpb
Tpb
Correlation of Map Units
3953000
Tbr
Qc/Tcc Tct
Tcc
Qc/Tcct
Qec
Qe
Qbt
Qt/Tpa
Tcc
Qec
Qec Tpv Qt
Tpa
Qbt
Qec
Qbo
Tbr
Qec
Tsf?
El Cajete Member (Valles Ryolite) (Quaternary) - White to beige pyroclastic fall deposits, including pumice, ash, crystals, and lithic
fragments associated with the ~50 to 60 ka eruption of the El Cajete Member of the Valles Rhyolite. Primary deposits are exposed in at
least two active mines in the northwest corner of the quadrangle where the unit is poorly to moderately sorted. Typically, however,
exposures of this unit are reworked, displaying few bedding features. Phenocryst content of pumices is generally less than 10% and
includes quartz, sanidine, and biotite. Many of the hills in the northern portion of the quadrangle are covered with >1 meter of primary
or reworked tephra. To the south the tephra thins significantly and typically is exposed as isolated patches along hillslopes or capping
terrace and other alluvial deposits along drainage bottoms. Maximum thickness in primary deposits exceeds 5 meters.
Tbr
Tbp
Qc
Tcc Tcc
Qt
Tpb
Qec
Qec
Tpb
Tpv
Qec
Qec
Tpb
Tpv
Qe
Qbt
Qal
Tpa
Qec
Tpv Tpb
Tpbi
Qec
Qc
Tpv
Tpb
Tpv
Tbp
Tpd
Tcc
Tpv
Tcc
Qt
Qec
16
Qec
Tbp
Tpv
TpbTpa
Tpb Tpv
Qec
7
Landslides (Pleistocene to Holocene) — Slump or block slides that remain nearly intact after detaching from a steep slope or cliff, or
unsorted, chaotic debris emplaced during a single detachment event from a steep slope or cliff. Fan-shaped deposits occur where debris
spread out on valley floor. Thicknesses highly variable.
Qc Tct
Qt
Tpb
Qt
Qls
Tbr
24
Tpb Tpa
Qc
Tpv Qec
Undifferentiated terraces and alluvium (Upper Pleistocene to Holocene).
Tbp
Qec
Qec
Tpv
Tpv
Tpv
Tpb
Tpb
Qal
Qec
Qtal
Qc
Tpa
Tbp
Qec
Tpv Tpb
Tpb
Tpv
Tpa
Qec
Tpa
Tpb
Tpb
Qec
Qal Tpv
Tpb
67
Terraces (Upper Pleistocene to Holocene) — Alluvial deposits near the margins of modern streams or older perched floodplain
deposits. Most are fill terrace deposits of sand, silt and gravel < 10 m above modern drainages. Maximum thickness is <10 m.
Qec
Tpb
Qec
Tpa
3949000
Tbr
Tpd
Tpb
Tpb
Tpb
30 35
Qt
3954000
12
Qec
Qec
16
Tpbi
Qc
Tpa
Tpa
Tpv
Tpv
3955000
Qec
Tpv
Tpb
Qc
Tpa
Tpb
Tpv
Upland alluvium, colluvium, and eolian deposits, undivided (Upper Pleistocene to Holocene) — Poorly sorted alluvial gravel,
sand, and silt interbedded with fine-grained, well-sorted eolian sand and silt. May be locally interbedded with El Cajete ash (Qec).
Commonly found in flat, broad areas adjacent to major drainages on the flat tops of ridges and divides in the southwest portion of the
quadrangle. Generally <1 m thick.
Tpa
Qec
Tpb Tpv
Tpv
Qe
Qtal
Tpb
Tpv
Qec
Tpb
Qec
Qec
Tpa
Tpb
Colluvium (Upper Pleistocene to Holocene) — Poorly-sorted talus, debris, and colluvium in wedge-shaped deposits on hill slopes.
Especially common where mesas and cuestas are capped by intermediate to mafic lavas or Tertiary gravels. Thickness can locally
exceed 5 m.
Qtal
Qec
Tpb
Qbo
Qec
Qec
45
Qc
Qbt
Tpa
Tpa
Qc
Qc
3956000
Qc
Qec
Tpd
Qal
Tpa
Tpb
Alluvium (Upper Pleistocene to Holocene) — Alluvial deposits in modern drainage bottoms. Deposits include conglomerates, sands,
and silts. Holocene terrace deposits less than 1 meter above drainage bottoms are included. Maximum thickness can exceed 5 m.
Qc
QboQec
Qec
Tpa
Qal
Qec
Qc
Qec
Tpb
40
80 Qec
Tpb Tpb
Tpbi
80
Tpb
Qec
Tpbt
Tpb 40 Tpv 7Qec
Ql
Qt
Qec 25
Tpv Tpv 32
Qec
Qt
Tpd
Tpa
Qc
Qbt
Tpa
Tpa
Qec
3951000
Qbo Qec
Tpb
Tpv
3950000
Tpa
Tpa
Qec
Qal
Qec
Qec
Qt
Tpb Tpa 14
Qec
The volcanic rock names used on this map are based on field identification and may not reflect the true rocks names based on geochemistry (see
report).
Qec
QbtQec
QboQec
Tpa
Qec
3952000
Qc
Tpb
8
Tpbhd
QbtQbt
Qec
Tpa
Tpa
3
Tpv
TpaQtal
DESCRIPTION OF MAP UNITS
Quaternary
Qec
QcTpb
Tpv Tpv
TpbTpv
Tpv
Tpv
Qbt
Tpb
Qec
Tpv
Tpv
Qc
Tct
Tpv
Tct
Tpv
Qec Tpb
Tpb Tpv
Tpb Tpv
Tpv
Tpv
Qec
3954000
Tpb
6
Qc
Qec
Qec
Tpb
Qc
Qc Ql
Tct
Qec
Qbt
Qt
Qec
Tpa
Qec
Qt Tpb
Tpb
Tpb Tpb
Tpv
Tpv
Tct
QcQal
TctTpv
Qc
Qbt
Qec
Qec
Tpb 11
7
Qbt
Qc
QbtQal
Qec
Qc
Qec
Qt Qbt
35°45'0"N
3957000
Qec
Tpbhd
364000
Qtal
Qt
Tct
Qal
363000
Qec
Tpv
Tpa
Qal
Tpv
362000
Tpa
Qal Tpv
Qt
Tbr
Tbr
Tpa
Qbt
Qbt
Tpa
3956000
Tpa Tpa
Qbt
Tpa
Qc
Qtal
Tbr
Qec
Qc
Qt
361000
Tpa
Qbt
Qbo
Tpbhd
Tpbhd
Qal
360000
Qt Qec Tpv Tpbhd
Tpv
Qbt
Qec
Qec Tpbhd
Tpv
Tpbhd
Qbt
Qec/Qt
Qbo
Qec
359000
Qec
Qec
Tpbhd
Tpbhd
Qec
Qc/Qal
358000
Qec
QbtQt
Qbt
Qal
Qbt
Qal Qbo Ql
Qec
Qec
Tpbhd
QecQal
Qec/Qt
357000
Tertiary
354000
NMBGMR Open-file Geologic Map 74
Last Modified 13 JUNE 2007
106°30'0"W
Triassic
353000
106°32'30"W
Quaternary
106°35'0"W
Permian
106°37'30"W
Location of geologic cross section.
Geologic contact. Solid where exposed or known, dashed
where approximately known, queried where uncertain.
Normal fault, ball-and-bar on downthrown side. Solid where
exposed, dashed where approximately known,
dotted where concealed.
15
Strike and dip of bedding.
Strike and dip of volcanic foliation.
Volcanic vent. Queried where uncertain.
1
2623 Via Caballero del Norte, Santa Fe, NM, 87505
2
Department of Earth and Planetary Sciences, Washington
3
University, St. Louis, MO 63130
NMBGMR, 801 Leroy Pl., Socorro, NM, 87801
4
Department of Geology, Queen's College, Cambridge University, CB39ET, UK
5
Arizona Geologoical Survey, 416 W. Congrss St., Tuscon, AZ, 85701
6
Los Alamos National Laboratory, Los Alamos, NM, 87545
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).
Bear Springs Peak Cross Section A - A’
A
New Mexico Bureau of Geology and Mineral Resources
New Mexico Tech
801 Leroy Place
Socorro, New Mexico
87801-4796
west
Hondo
Canyon
8000
feet ASL
Qec
Qec
Tpv
[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:
7000’
Qal
Qt
Tpa
Ql
@c
5000’
Tpv
Tpv
Tpb
Tpv
Tpb
Qal
Tcc
Tpv
Tcct
Tcct
Tcc
Qt
Tcct Qal
Tcc
TKu
TKu
Qal
Qtal
@u?
@u?
Tcct
Qal
Tcct
Qec
Tpa
Qal Tcct
TKu
Pu?
Pu?
Tcd
TKu
@u?
@u?
@m
Tbr
Tcc
TKu
Tbr
Qc Tglp
Qal
@u?
@u?
Pu?
Pu?
Tglp
Tbt
Qal
Tglp
7000’
TKu
@u?
Pu?
Pu?
8000
feet ASL
La Jara
Canyon
Tbt
Tcd
Tcc
Tpv
@u?
east
Cerrito
Yelo
@cs
Pu?
http://geoinfo.nmt.edu/publications/maps/geologic/ofgm/home.html
Tpb
Tpb
Qtal
Tpa
TKu
@u?
6000’
Tpa
Qec
Qal
Tpv
Tpb
A’
Pu? Pu?
6000’
Pu?
5000’