NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES
NMBGMR Open-file Geologic Map 88
Last Modified 16 November 2009
A DIVISION OF NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY
GEOLOGIC CROSS SECTIONS
A΄
A
West
Telephone
Canyon
Rio Cebolla
Calaveras
Canyon
Qbt
Qvsa
9,000
Qdf
Qvrc
Qbo
Qal
Qbo
Qbo
Qal
Qdf
Qal
Tab
Pa
Tab
Tab
Pa
V.E. = 1.67
San Antonio
Creek
Qbt
Qbt
East
Qbt
Qbt
Qbt
Qbo
Qal
Well B
(projected)
Pa
Pa
Pa
Pa
&m
8,000'
7,600'
B΄
B
Southwest
Northeast
Qbt
Well D
(projected)
Qbt
Ttd
Qbt
Qcbt
Qal
GT1
Ttd
Tpa
Ts
Tpa?
Qbt
Qbt
Qbo
San Antonio
Creek
Qbt
Rio Cebolla
Qvsa
Qc
Qvrcu
Qdf
Qbo
Qcbt
Qvsa
Qc
Qbo
9,000
Feet (ASL)
WC 23-4
Qvrcl?
Qbt
Qdf
8,000'
Pa
Pa
Pa
Pa
&m
&m
&m
7,000'
&m
&s
&s
&s
Westward view of outcrop above San Antonio Creek, which forms the northwest margin of the Valles Caldera
in the Seven Springs quadrangle. Immediately above the creek, red Permian sandstone of the Abo Formation
(Pa) is overlain by the Otowi Member of the Bandelier Tuff (Qbo). The Otowi darkens upwards to the cliffs
on the skyline due to vapor phase alteration of the tuff.
&s
6,000'
Xu
Xu
Xu
Xu
T.D. = 6,445 ft
5,000'
V.E. = 1.67
C΄
C
Well A
(projected)
Qbt
Tpa
Tab
Qbo?
Tpa
Ts
Ttd
Tab
Tpv
Qal
Pa
Pa
9,000
Feet (ASL)
San Antonio
Creek
EXPLANATION OF MAP SYMBOLS
Qvsa
Qvrcu
Qdf
Qvrcl
Tpa
block
8,000'
A
A'
Geologic contact. Solid where exposed or known, dashed where
approximately known, dotted where concealed or inferred.
Qdf
Pa
&m
&s
Normal fault, ball-and-bar on downthrown side. Solid where
exposed, dashed where approximately known, dotted where
concealed.
7,000'
&m
&m
Trace of axial plane of anticline, dashed where approximately
known, dotted where concealed.
&s
&s
Trace of axial plane of syncline, dashed where approximately
known, dotted where concealed.
6,000'
25
Xu
Xu
Xu
8
5,000'
V.E. = 1.67
CORRELATION OF MAP UNITS
Location of geologic cross section.
(Ma) ERA PERIOD EPOCH
0
Holocene
0.01
QUATERNARY Pleistocene
2.6
5.3
Strike and dip of bedding
Strike and dip of foliation
VOLCANICLASTIC
SEDIMENTARY
AGE
23.0
Location of radiometric date
33.9
Hr
Qa
Qal
Qaf
Qt
Qoa
Qls Qlssa Qla
Qcbt
Qc
VOLCANIC
Qvsa
Qdf
Qct
Qvset Qvrc Qvrcu Qbt
Qvrcl
Qbo
Ttd
Pliocene
NEOGENE
GT-2
TERTIARY
Bend In
Section
Ts
Tpv
Tpa
Tpb
Tsf
Miocene
Tp
Ta
Tab
PALEOGENE
PC-2
Bend In
Section
Southeast
CENOZOIC
Northwest
Oligocene
Tr
299
Qct
Quaternary
Hr
Modern road fill (Holocene).
Qa
Alluvium (Holocene) – Fine-grained reddish tan silt capping hills of Abo Formation in southwest corner of T20N R2E sec. 17 that are
most likely eolian deposits. 1 to 5 m thick.
Qal
Alluvium (Holocene) – Undivided fluvial gravel, sand, silt, and clay deposited by major drainages and their tributaries. Up to 5 m
thick.
Qaf
Alluvial Fan (Holocene) – Debris flow and fluvial deposits associated with side drainages depositing fan material on the floodplain of
major modern drainages. Some of the fan deposits are particularly evident as a consequence of the August, 2002, Lakes forest fire near
Fenton Lake. Maximum thickness ~ 10 m.
Qt
Qoa
Qcbt
Terrace deposits (middle Pleistocene to Holocene) – Alluvial silt, sand, cobble, and boulder deposits of predominantly Bandelier
Tuff along Rio Cebolla. Proterozoic granitoids and Pedernal Chert recycled from the late Oligocene to early Miocene lower Abiquiu
Formation exposed north of the area form terraces in Calaveras Canyon. Terraces along San Antonio Creek near La Cueva contain
rounded rhyolite and andesite pebbles and cobbles. 1 to 5 m thick.
Old alluvium (middle Pleistocene to Holocene) – Old valley fill composed of gravel, sand, silt, and clay topped by a graded surface
that is 3 to 15 m above modern grade. This unit is well developed along Rito Peñas Negras in the northwest corner and along Sulphur
Creek in the southeast corner of the map. Qoa in the southeast corner of the map is composed of sandstone with rhyolite clasts overlain
by 2 to 2.5 m of peat. The unit is capped by siltstone and pumaceous sandstone. This unit may have formed during blockage of drainage
through the narrow cut in the Redondo Creek Rhyolite just to the southwest of the deposit. ~ 5 m thick.
Qc
Qls
Landslide deposit (middle Pleistocene to Holocene) – Undivided landslide deposits composed of locally derived, cohesive blocks of
Bandelier Tuff or rhyolite lava. Generally associated with a head scarp in their source area. Varies in thickness from ~ 5 to 50 m.
Qla
Monolithic landslide deposit (middle Pleistocene to Holocene) – Landslide deposit composed entirely of cohesive blocks of San
Antonio Mountain rhyolite lava. Restricted to one exposure near the top of an extensive Qls deposit along the east side of San Antonio
Creek in section 5, T19N, R3E. ~ 1 to 5 m thick.
Qvsa
x x x x x x
x xQvset x
x x x x x
Qvrc
N
Base map from U.S. Geological Survey 1965, from photographs taken 1965 field checked in 1990 edited in 1993.
1927 North American datum, UTM projection -- zone 13N
1000-meter Universal Transverse Mercator grid, zone 13, shown in red
Geologic map of the
Seven Springs quadrangle,
Sandoval County, New Mexico.
1:24,000
1
NACIMIENTO PEAK
JAROSA
1000
CERRO DEL GRANT
SEVEN
SPRINGS
0
1
NEW MEXICO
RANCHO DEL
CHAPARRAL
0.5
VALLE SAN
ANTONIO
1000
0
2000
0.5
3000
1 MILE
4000
5000
6000
0
7000 FEET
1 KILOMETER
May 2004
Qvrcl
CONTOUR INTERVAL 40 FEET
by
1
Shari A. Kelley , G. Robert Osburn 2, Charles A. Ferguson 3,
Kirt Kempter 4, and Magdalena Osburn 2.
NATIONAL GEODETIC VERTICAL DATUM OF 1929
SAN MIGUEL
MOUNTAIN
JEMEZ SPRINGS
REDONDO PEAK
Magnetic Declination
November, 2005
10º 00' East
At Map Center
1
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
New Mexico Bureau of Geology and Mineral Resources
Open-file Geologic Map 88
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
Qvrcu
Qdf
New Mexico Bureau of Geology and Mineral Resources, 801 Leroy Pl., Socorro, NM, 87801
2
Campus Box 1169, Washington University, St. Louis, MO, 63130
3
119 North Fork Rd., Centennial, WY, 82055
4
2623 Villa Caballero del Norte, Santa Fe, NM, 87505
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.
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.
Qbt
Ts
San Antonio Mountain Rhyolite; Valles Rhyolite (late Pleistocene) – Phenocryst-rich (30%) rhyolite lava. The lava contains ~1015% 1 to 5 mm subhedral to anhedral quartz, 5-10% 1 to 3 mm subhedral to anhedral sanidine, <5% 1 to 2 mm subhedral to euhedral
plagioclase, sparse 1 mm biotite, sparse <1 mm hornblende, and sparse <<0.5 mm opaques. Goff and Gardner (1980) describe a
similar flow in the Sulphur Springs area to the east, although they found trace amounts of clinopyroxene. Prominent ridge and valley
topography in the Mushroom Basin area is defined by alternating bands of flow-foliated coherent facies crystalline matrix, spherulitic
lithophysal, and vitric matrix lava. The valleys tend to be composed of the slightly less resistant spherulitic lithophysal facies, which
is transitional between the other two facies. The lava overlies the Redondo Creek Rhyolite to the south and Abo Formation to the west
with thin intervening deposits of caldera fill deposits (Qdf). Spell and Kyle (1989) recalculated the sanidine K-Ar ages of Doell et al.
(1968); the ages are 0.549 ± 0.015 Ma for San Antonio flow I (Qvsa1) and 0.447 ± 0.015 Ma for San Antonio flow II (Qvsa2). Spell
and Harrison (1993) determined an 40Ar/39Ar age on sanidine of 0.557 ± 0.004 Ma on two samples of Qvsa2. The lava is 61 m thick in
drillhole WC23-4. Maximum exposed thickness above San Antonio Hot Spring is ~110 m.
Ttd
Redondo Creek Rhyolite, upper flow unit (middle Pleistocene) – Moderately phenocryst-rich (10-15%) rhyolite lava. The lava
contains about 10% 0.5 to 3.0 mm, subhedral to euhedral, melt-inclusion rich plagioclase, 1-2% 0.5 to 1.5 mm subhedral sanidine, <1%
0.5 to 1.0 mm biotite and hornblende, and sparse <1 mm clinopyroxene, and <<0.5 mm opaques. Phillips (2004) obtained an 40Ar/39Ar
age of 1.208 ± 0.017 Ma on sanidine from this flow just to the east of the map area in the NE corner of section 4, T19N, R3E. 0 to 150
m thick.
Redondo Creek Rhyolite, lower flow unit (middle Pleistocene) – Moderately phenocryst-rich (10-15%) rhyolite lava. The lava
contains ~10% 0.5 to 3.0 mm subhedral to euhedral, melt-inclusion rich plagioclase, ~1% 1 to 2 mm clinopyroxene, <1% <1 mm
opaques, and sparse <1 mm biotite and hornblende. Phillips (2004) obtained an 40Ar/39Ar age of 1.239 ± 0.017 Ma on sanidine from
a vitric matrix, coherent facies lava adjacent to a probable intrusive contact with the Qsrc unit along State Highway 4 in the extreme
southeast corner of the map area. 0 to 150 m thick.
Caldera-fill unit (middle Pleistocene) – A unit of undifferentiated sedimentary deposits within the Valles caldera. On the south end of
Thompson Ridge, caldera-fill sedimentary deposits are clearly interbedded with the Redondo Creek Rhyolite (351999E 3972850N, NAD
27). Undivided caldera fill is shown in the southeast corner of the map area in places where the deposits are between Redondo Creek and
San Antonio Mountain lava or are below the lower member of the Redondo Creek Rhyolite. Maximum thickness is ~60 m. The caldera
fill sequence between the Redondo Creek flows is a heterogeneous sequence of conglomerate, breccia, pumiceous sandstone, and silty
mudstone that is complexly interbedded with the Redondo Creek Rhyolite. Includes lacustrine deposits (Qvs) composed of angular
clasts of laminated ashy siltstone (shoreline deposits), pumiceous sandstone, claystone with plant debris, and finely laminated ashy
siltstone. The unit correlates, along with the sedimentary unit of Deer Canyon (Qdcs), with the caldera-fill unit of Smith et al. (1970).
The deposits are restricted to areas east of San Antonio Creek. For the most part, silicifed zones adjacent to intrusive contacts with the
rhyolite are the only areas where the unit crops out (see outcrops of thin- to medium-bedded pumiceous sandstone along a graded gravel
road in sections 8, 9, and 16, T19N, R3E). In most areas, the unit is identified by the presence of rounded to angular clasts, ranging
from cobbles to boulders and very large blocks, of granite (Proterozoic), red feldspathic quartz sandstone and siltstone (Abo Formation),
Paleozoic limestone (Madera Formation), andesite and dacite lava (Keres Group), and welded, phenocryst-rich rhyolite ash-flow tuff
(Bandelier Tuff) in colluvium. The unit also contains exceptionally large (megabreccia) blocks (possibly greater than 400 m across)
of distinctive, vitric-matrix, 15% plagioclase porphyritic andesite that is mapped separately (Qxp). The unit overlies the unit of Deer
Canyon; maximum exposed thickness about 120 m.
Upper Bandelier Tuff, Tshirege Member (middle Pleistocene) – White to orange to pink welded to non-welded rhyolitic, ash-flow
tuff (ignimbrite) containing 15-20% phenocrysts of sanidine and quartz, rare microphenocrysts of black clinopyroxene and trace
microphenocrysts of hypersthene and fayalite. Sanidine typically displays blue iridescence. Contains ~ 30% pumice lapilli. Consists of
multiple flow units in a compound cooling unit (Smith and Bailey, 1966; Broxton and Reneau, 1995). Upper flow units generally more
welded than lower ones. Locally contains a thin (<2 m) laminated, pumice fall and surge deposit at base of unit (Tsankawi Pumice) that
contains roughly 1% of hornblende dacite pumice (Bailey et al., 1969). Locally contains accidental lithic fragments of older country
rock entrained during venting and pyroclastic flow; the fragments are concentrated in a unit is that is located approximately a thrid of the
way up from the base of the tuff (subunit III of Smith and Bailey, 1966) and contains 5-10% lithic fragments. Qbt forms conspicuous
orange to tan cliffs throughout the area; originated from eruptions that formed Valles caldera. 40Ar/39Ar age is 1.22 ± 0.01 Ma (Izett and
Obradovich, 1994; Spell et al., 1996). Maximum observed thickness ~ 80 m.
The contact between the Otowi and Tshirege members of the Bandelier Tuff is particularly well exposed in the cliffs west of Fenton
Lake. Here 1.5 to 2.5 m of Tsankawi pumice is visible at the base of the Tshirege member. The Tshirege member filled a relatively
rugged topography that developed during the 400,000 years between eruptions; local relief is generally on the order of 20 to 30 m (see
cross sections). The base of the Tshirege member generally dips toward the southwest, away from a drainage divide north of the map
area and away from the caldera rim. Elevations of the base of the Tshirege member range from 2680 to 2740 m (8800 to 9000 ft) in the
north central part of the area and along the topographic rim of the caldera to about 2500 m (8200 ft) near Fenton Lake. The filling of
a paleo-low along the Rio Cebolla at the south edge of the community of Seven Springs dropped the contact to an elevation of 2400 m
(7880 ft) with local relief of ~ 100 m (330 ft).
Tchicoma Formation dacite (Pliocene) – Light gray to pink flows and rubbly basal vitric flow breccias. Porphyritic and contains 1015% 2 to 6 mm euhedral plagioclase, ~1% 2 to 10 mm hornblende, and 1% biotite phenocrysts. Flows are common north and northeast
of Fenton Hill. K-Ar age of prominent flow in the center of T19N, R3E, section 7 above Forest Road 376 to San Antonio Hot Springs
on the western wall of the caldera is 4.21 ± 1.3 Ma. (Gardner and Goff, 1984). The unit overlies the Paliza Canyon Formation andesite
and basalt. Thickness is 30 to 40 m.
Pa
PENNSYLVANIAN
542
&m
&s
Xu
PROTEROZOIC
Geochronology results for volcanic rocks in Seven Springs quadrangle. Samples
run at the New Mexico Geochronology Laboratory at New Mexico Tech.
Sample
UTM coordinates
(NAD 27)
Lithology
40
Ar/39Ar age (Ma)
FJ-0434 13S 349992 3971680 basalt lava clast in Paliza
Canyon volcaniclastic sediment
8.93 ± 0.11
FJ-0403 13S 349256 3972491
Paliza Canyon basalt
8.88 ± 0.05
FJ-0430 13S 350160 3971580
basalt clast in Paliza
Canyon volcaniclastic sediment
9.26 ± 0.14
SS-05
Paliza Canyon andesite
8.20 ± 0.09
13S 348657 3972435
Keres Group Volcanic and Volcaniclastic Rocks (Miocene)
Tpa
Paliza Canyon Formation andesite (Miocene) – Dark gray, plagioclase porphyritic andesite lava flows. The andesite contains 10-20%
2 to 7 mm euhedral to subhedral, zoned plagioclase, and up to 2% 1 to 4 mm clinopyroxene. 40Ar/39Ar age is 8.20 ± 0.09 Ma. (this study).
Flows are common north and northeast of Fenton Hill and along the western topographic rim of the caldera. The andesite is interbedded
with volcaniclastic rocks (Tpcs), rests on basalt and is overlain by Qbo. Maximum exposed thickness is ~ 20 m.
Two blocks of Paliza Canyon andesite are preserved within the caldera. This moderately phenocryst-rich (10-15%) andesite lava
contains ~10-12% 0.5 to 5 mm euhedral, melt-inclusion rich, strongly zoned plagioclase, and ~2-3% <0.5 mm subhedral to euhedral
clinopyroxene. The lava has a distinctive black vitric matrix that contains ~20% <<0.5 mm plagioclase microlites. An apparently
continuous exposure (~0.1 km2) of flow-foliated lava that appears to grade up into a carapace breccia underlies sedimentary deposits
(Qcf) in the extreme southeast corner of the map area. A smaller exposure of monolithic autobreccia underlies the lower flow unit of
the Redondo Creek Rhyolite (Qvrcl) with less than 50 cm of intervening heterolithic sandy conglomerate at the mouth of Water Canyon
in section 8, T19N, R3E. The andesite lava is thought to represent megabreccia blocks of Paliza Canyon (Tpa) within the caldera-fill
sequence.
Tpv
Ignimbrite from the Cerro Seco Rhyolite dome; Valles Rhyolite (middle Pleistocene) – Pink ignimbrite and lithic-rich ignimbrite
with phenocrysts of quartz and sanidine on Upper Abiquiu Formation in San Antonio Creek along the east edge of the quadrangle.
Lithic fragments include Tshirege Member, Bandelier Tuff. Possibly correlative to the ignimbrite beneath the Cerro Seco rhyolite (0.8
Ma; Spell and Harrison, 1993; Goff et al., 2006), but could be a pyroclastic deposit related the San Antonio Mountain Rhyolite. ~4 m
thick.
Redondo Creek Rhyolite, undifferentiated (middle Pleistocene) – Moderately phenocryst-rich (10-15%) plagioclase-sanidinebiotite-pyroxene rhyolite. The unit is complexly interbedded with conglomerate (include boulders of Paliza Canyon andesite up to 1.5
m across) and sandstone (Qdf) in the southeast corner of the map area. The unit consists of at least two flow units (Qvrcl and Qvrcu)
separated by a relatively thick sequence of debris flow sediments. The flows are indistinguishable in the field, but the lower unit can
be distinguished in thin-section by the relative rarity of sandine phenocrysts and differences in the abundance of mafic phenocrysts.
Two small exposures of the lava are found along the extreme east edge of the map area in section 9, T19N, R3E that are slightly more
phenocryst-rich (15-20%) than the other flows. These exposures (mapped as Qvrc) probably represent an older flow unit, but poor
exposure of the intervening sedimentary unit (Qdf) makes it impossible to determine how these exposures correlate with the upper and
lower units recognized to the west. A thin (<15 m thick) sequence of vitric tuff (Qvt) that underlies San Antonio Mountain Rhyolite
to the south of San Antonio Hot Spring may be part of the Redondo Creek Rhyolite. The deeply eroded lavas display a wide variety of
coherent and incoherent (autobreccia) facies textures ranging from vitric matrix, to crystalline matrix with lesser spherulitic lithophysal
zones. The lava is also characterized by extensive zones of iron oxide-stained, variably silicified and argillic-altered zones, but abundant
areas of unaltered vitric matrix lava are also present. The lavas are thought to have been erupted from a vent in the Sulphur Springs area
to the east. The unit underlies the San Antonio Mountain Rhyolite (Qvsa), and overlies the sedimentary unit of Deer Canyon (Qdcs). 0
to 200 m thick.
Tertiary sedimentary units, undifferentiated (Pliocene to Miocene (?)) – Two packages of poorly exposed sedimentary units are
present along the western wall of the caldera. One unit is characterized by pebble to cobble-sized angular pieces of Abiquiu sandstone
and Pedernal Chert. In one locality, this unit appears to overlie the Tschicoma Formation dacite. In addition, the unit is present upslope
of the prominent Tschicoma dacite flow just above Forest Road 376. This unit could be a debris flow composed entirely of upper Abiquiu
Formation sandstone resting on the Tschicoma dacite, and in places, on Paliza Canyon Formation lavas, or it could be poorly preserved
upper member of the Abiquiu Formation, with the younger lavas inset against the sedimentary rocks. The second sedimentary package
that is exposed on the east side of the prominent white outcrop on Highway 126 east of Fenton Hill is a mix of rounded Tschicoma
dacitic and Paliza Canyon volcanic clasts with occasional Abiquiu Formation sandstone in a tan sandy matrix (reworked Ojo Caliente
sandstone?). The unit is up to 70 m thick.
Polvadera Group Volcanic Rocks (Pliocene)
Alluvium and ephemeral lacustrine deposits (early Pleistocene to Holocene) – Deposits of alluvium and colluvium in topographically
confined basins developed on top of the San Antonio Mountain and Redondo Creek rhyolite lavas. Most of the basins appear to drain
internally. ~1 to 5 m thick.
Valles Group Volcanic and Volcaniclastic Rocks
Lower Bandelier Tuff, Otowi Member (early Pleistocene) – White to pale pink, rhyolitic ash-flow tuff containing 15-20% phenocrysts
of sanidine and quartz, and sparse mafic phenocrysts; sanidine may display a blue iridescence. Qbo is highly welded through the central
portion of the quadrangle, with well-developed pumice fiamme. Contains abundant accidental lithic fragments near the top of the unit.
The stratified pumice fall and surge deposit at the base of the unit (Guaje Pumice) is not found in this area. Qbo discontinuously fills
in rugged topography on a pre-Toledo caldera age volcanic surface and can form spectacular tent rocks; the upper surface is quite
undulatory due to erosion prior to the eruption of the Tshirege member (Qbt). Very difficult to distinguish from upper Bandelier Tuff
in hand samples; best distinguished by more abundant lithic fragments, less abundant iridescent sanidine, and stratigraphic position
beneath the Tsankawi Pumice and/or Cerro Toledo interval. Originated from eruptions that formed Toledo caldera; 40Ar/39Ar ages 1.61
± 0.01 to 1.62 ± 0.04 Ma (Izett and Obradovich, 1994; Spell et al., 1996); maximum exposed thickness about 180 m.
Tertiary
Bandelier Tuff colluvium and related hillslope deposits (middle Pleistocene to Holocene (?)) – Hillslope colluvial deposits composed
of pebble to boulder-sized, angular clasts of Bandelier Tuff derived from mesa cap rocks. Poorly sorted and poorly stratified. Matrix and
clast supported. Significant accumulations found on north facing slopes. Varies in thickness from ~ 5 to 50 m.
Undivided colluvium (middle Pleistocene to Holocene) – Hillslope colluvial deposits composed of pebble to boulder size clasts from
a variety of lithologies. Varies in thickness from ~ 5 to 50 m.
Qlssa
Qbo
PERMIAN
318
PRECAMBRIAN
DESCRIPTION OF MAP UNITS
Cerro Toledo Formation deposits (early to middle Pleistocene) – Fluvial gravel and sandstone deposits underlie the air-fall Tsankawi
Pumice of the Tshirege member of the Bandelier Tuff and overlie the Otowi member of the Bandelier Tuff. These deposits are found in
only two places in the area and the outcrops are too small to show on the map. West of Fenton Lake at 13S 343880E 3972840N, ~ 1 m
of coarse, pebbly sandstone containing pumice, lithics and ash recycled out of the Otowi Member is preserved. In Schoolhouse Canyon
at 343154E 3977703N, clasts of sub-round to well-rounded, pebble to boulder sized Abo Formation sandstone is present between Qbo
and Qbt. Stratigraphically equivalent to the Cerro Toledo Formation epiclastic sediment and tephra deposits on the Pajarito Plateau
(Broxton and Reneau, 1995). <1 m thick.
PALEOZOIC
251
Tpb
Tsf
Ta
Paliza Canyon Formation volcaniclastic sedimentary rocks (Miocene) – Volcaniclastic conglomerate, and pebble-cobble sandstone
interbedded with and overlying the volcanic rocks of the Keres group. Poorly exposed in most areas; the unit is most commonly
manifested as rounded pebbles to boulders of andesite, dacite, basalt, and occasional Abiquiu Formation and Permian Abo Formation
sandstone in colluvium. The unit is well exposed in a roadcut along Highway 126 beneath a Paliza Canyon andesite flow, with rounded,
altered andesite and basalt clasts in a sandy altered matrix. The name of this unit is modified from the original definition of Bailey et al.
(1969) and follows the definition of Smith and Lavine (1996). Maximum thickness is 25 m.
Paliza Canyon Formation basalt (Miocene) – Black to dark brown massive to vesicular lava flows containing up to 10% euhedral
1 to 2 mm plagioclase, 5-10% 0.5 to 2.0 mm iddingsite and 1-5% 0.5 to 1.5 mm pyroxene. Basalt flows are exposed on the western
rim of the caldera near Highway 126, where they appear to fill narrow paleocanyons cut in the Santa Fe Group and Abiquiu Formation
sandstones and are locally overlain by the Paliza Canyon andesite. An 40Ar/39Ar age of 8.88 ± 0.05 Ma. was determined for this basalt
(this study). Subrounded basalt boulders and cobbles in volcaniclastic conglomerate interbedded with Paliza Canyon andesite flows at
Fenton Hill yield 40Ar/39Ar ages of 8.93 ± 0.11 and 9.26 ± 0.14 Ma. (this study). The basalt likely correlates with 9.1 to 9.4 Ma. basalt
lavas on Borrego Mesa in the Ponderosa quadrangle (Osburn et al., 2002) and the basalt lavas in Church Canyon on the Jemez Springs
quadrangle (Kelley et al., 2003). Thickness 3 to 15 m.
Doell, R.R., Dalyrymple, G.B., Smith, R.L. and Bailey, R.A., 1968, Paleomagnetism, potassium-argon ages and geology of rhyolites and
associated rocks of the Valles caldera, New Mexico: Geological Society of America, Memoir 116, p. 211-248
DuChene, H.R., 1974, Pennsylvanian rocks of north-central New Mexico: New Mexico Geological Society, Guidebook 25, p. 159-162.
Eberth, D.A., 1987, Stratigraphy, sedimentology and paleoecology of Cutler Formation redbeds (Permo-Pennsylvanian) in northcentral New Mexico [Ph.D. dissertation]: Toronto, University of Toronto, 264 p.
Eberth, D.A. and Berman, D.S., 1993, Stratigraphy, sedimentology and vertebrate paleoecology of the Cutler Formation redbeds
(Pennsylvanian-Permian) of north-central New Mexico: New Mexico Museum of Natural History and Science, Bulletin 2, p.
33-48.
Goff, F., Reneau, S.L., Goff, C.J., Gardner, J.N., Drakos, P., and Katzman, D., 2006, Geology of the Valle San Antonio 7.5 minute
quadrangle, Sandoval and Rio Arriba counties, New Mexico: New Mexico Bureau of Geology and Mineral Resources OFGM132, scale 1:24,000.
Tr
Tab
Abiquiu Formation and Ritilto conglomerate, undifferentiated (Oligocene to Miocene) – Shown on cross-sections only. Includes
upper and lower members and Pedernal chert. Upper and lower members were not distinguished on the well logs.
Goff, F. and Gardner, J.N., 1980, Geologic map of the Sulphur Springs area, Valles caldera geothermal system, New Mexico: Los Alamos
Scientific Laboratory, Map LA-8634-MAP, 2 sheets, scale 1:5000.
Gardner J.N., and Goff, F., 1984, Potassium-argon dates from the Jemez volcanic field: Implication for tectonic activity in the northcentral Rio Grande rift: New Mexico Geological Society Guidebook 35, p. 75-81.
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.
Izett, G.A. and Obradovich, J.D., 1994, 40Ar/39Ar age constraints for the Jaramillo normal subchron and the Matayama-Brunhes
geomagnetic boundary: Journal of Geophysical Research, v. 99(B2), p. 2925-2934.
Krainer, K., Vachard, D., and Lucas, S.G., 2005, Lithostratigraphy and biostratigraphy of the Pennsylvanian-Permian transition in the
Jemez Mountains, north-central New Mexico: New Mexico Museum of Natural History and Science Bulletin 31, p. 74-89.
PALEOZOIC
Lucas, S. G. and Krainer, K., 2005, Stratigraphy and correlation of the Permo-Carboniferous Cutler Group, Chama Basin, New Mexico:
New Mexico Geological Society, Guidebook 56, p. 145-159.
Abo Formation (Permian) – Red to white, medium- and thin-bedded, fine to medium grained, arkosic fluvial sandstone interbedded
with red and dark red micaceous siltstone and mudstone. Granule to pebble conglomerates composed mostly of rounded Proterozoic
white quartzite and pink granitic clasts are present locally. Pedogenic carbonate horizons are rare. The proportion of sandstone varies
laterally but does not seem to vary consistently vertically within exposed section. In fact, the Abo Formation in the Seven Springs area
is dominantly fine-grained, with few discontinuous channel sandstones. The discontinuous nature of the sandstones makes it difficult
to follow faults and folds across this interval. The sandstones are cross-stratified (typically trough and wedge-planar geometries) and
exhibit spectacular soft-sediment deformation. This unit, especially in the northwest corner of the quadrangle, may correlate with the
El Cobre Member of the Cutler Formation to the north (Lucas and Krainer, 2005). The Abo Formation locally contains malachite and
azurite deposits in channel sandstones, particularly in the northwestern corner of the quadrangle (Timmer, 1976). The base is transitional
with the underlying Madera Formation (or Guadalupe Box Formation of Krainer et al., 2005). It is equivalent to the Cutler Formation
to the north (Eberth,1987; Eberth and Miall, 1991, Eberth and Berman, 1993; Crabaugh, 1988; Lucas and Krainer, 2005). Maximum
exposed thickness ~ 150 m.
Northrop, S.A. and Wood, G.H., Jr., 1946, Geology of the Nacimiento Mountains, San Pedro Mountain and adjacent plateaus in parts of
Sandoval and Rio Arriba Counties, New Mexico: U.S. Geological Survey, Oil and Gas Investigations Preliminary Map 57.
Madera Group (Pennsylvanian) – Light-gray, thin to medium bedded fossiliferous limestone (micrite to skeletal wackstone), white to
buff quartzose sandstones, coarse-grained arkose, light-gray shale with subordinate arkosic limestone (Read and Wood, 1947; DuChene,
1974). Crinoids and brachiopods are the most common fossils. The upper part of the unit is transitional with Abo redbeds and includes
red arkosic sandstone and minor shale. Krainer et al. (2005) argue that the name Madera Group be abandoned and the name Guadalupe
Box Formation should be applied, instead. Following Woodward (1987), the top was mapped at the uppermost limestone bed that is ~
1 m thick. ~ 50 m exposed.
Sandia Formation (Pennsylvanian) – Shown on cross-sections only. Upper clastic part includes gray fossiliferous limestone, reddishbrown, fine- to coarse-grained sandstone, and brown to greenish-gray shale. Lower limestone member consists of light gray fossiliferous
to sandy limestone, with a few thin lenses of fine- to coarse-grained sandstone, and light gray siltstone. This interval is found only in
wells in this area and may include the Mississippian Arroyo Peñasco and Log Cabin formations.
PROTEROZOIC
Xu
Broxton, D., and Reneau, S., 1995, Stratigraphic nomenclature of the Bandelier Tuff for the environmental restoration project at Los
Alamos National Laboratory: Los Alamos National Laboratory Report LA-13010-MS, 21 pp.
Abiquiu Formation (Oligocene to Miocene) – Predominantly composed of white to tan, medium-grained, medium-bedded sandstone
that is well-cemented with a few interspersed lenses of green shale, red silt, and brown Pedernal chert. Silicified root casts are locally
present. The unit is exposed in a road cut along Highway 126 and along northern San Antonio Creek. The San Antonio Creek exposures
contain volcanic ash that are too fine-grained to date. Maximum exposed thickness ~ 10 m.
Ritilto conglomerate (Oligocene to Miocene) – A poor exposure of a pebble to cobble conglomerate composed of Proterozoic granitoids
and quartzite in a tan sandy matrix is found in northern San Antonio Creek. Maximum exposed thickness 10 to 20 m.
&s
Bailey, R.A., Smith, R.L. and Ross, C.S., 1969, Stratigraphic nomenclature of volcanic rocks in the Jemez Mountains, New Mexico: U.S.
Geological Survey, Bulletin 1274-P, 19 p.
Eberth, D.A. and Miall, A.D., 1991, Stratigraphy, sedimentology and evolution of a vertebrate-bearing braided to anastomosed fluvial
system, Cutler Formation (Permian-Pennsylvanian), north-central New Mexico: Sedimentary Geology, v. 72, p. 225-252.
Pedernal chert (Oligocene to Miocene) – White to clear chert. Forms a 1 m thick ledge on Abo Formation in the northwestern corner
of the quadrangle; overlain by the Tshirege Member of the Bandelier Tuff.
&m
Crabaugh, J.P., 1988, Depositional history of the Lower Permian Abo Formation and lower Meseta Blanca Member of the Yeso Formation,
north central New Mexico [Ph.D. dissertation]: Arlington, University of Texas, 214 p.
Santa Fe Group, Ojo Caliente (Miocene) – Tan to white to light pink sandstone that is poorly cemented, fine to medium-grained,
and consists of sub-round to angular grains of quartz, feldspar, mafic minerals and rare lithic fragments. High-angle cross-beds are
locally preserved. Exposed primarily in road cuts on Highway 126 between Fenton Hill and Fenton Lake. Correlation to the Ojo
Caliente Member sandstone exposed in the northern Jemez Mountains is based on relative stratigraphic position above fluvial rocks of
the Abiquiu Formation (or possibly Chama-El Rito of the Santa Fe Group) and below the 8.2 Ma. Paliza Canyon andesite and on the
presence of eolian features.
Tp
Pa
REFERENCES
Plutonic and metamorphic rocks (Proterozoic) – Shown on cross-sections only. Pink, coarse-grained granite, gray, coarse-grained
granodiorite, monzonite, quartz monzonite, gneiss, biotite-hornblende schist and amphibolite with dacitic dikes.
Phillips, E. H., 2004, Collapse and resurgence of the Valles caldera, Jemez Mountains, New Mexico: 40Ar/39Ar age constraints on
the timing and duration of resurgence and ages of megabreccia blocks [M.S. thesis]: New Mexico Institute of Mining and
Technology, Socorro, NM, 200 pp.
Read, C.B. and Wood, G.H., Jr., 1947, Distribution and correlation of Pennsylvanian rocks in Late Paleozoic sedimentary basins of
northern New Mexico: Journal of Geology, v. 55, p. 220-235.
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.
Smith, G.A., and Lavine, A., 1996, What is the Cochiti Formation?: New Mexico Geological Society, 47th Field Conference, Guidebook,
p. 219-224.
Smith, R.L. and Bailey, R.A., 1966, The Bandelier Tuff: a study of ash-flow eruption cycles from zoned magma chambers: Bulletin
Volcanologique, v. 29, p. 83-104.
Smith, R.L., Bailey, R.A., and Ross, C.S., 1970, Geologic map of the Jemez Mountains, New Mexico: United States Geological Survey
Map I-571, scale 1:125,000.
Spell, T.L. and Harrison, T. M. 1993, 40Ar/39Ar geochronology of post-Valles caldem rhyolites, Jemez volcanic field, New Mexico:
Journal of Geophysical Research, v. 98, p. 8031-8051.
Spell, T.L. and Kyle, E.R., 1989, Petrogenesis of Valle Grande Member rhyolites, Valles caldera, New Mexico: implications for evolution
of the Jemez Mountains magmatic system: Journal of Geophysical Research, v. 94(B8), p. 10,379-10,396.
Spell, T.L., Harrison, TM. and Wolff, J.A., 1990, 40Ar/39Ar dating of the Bandelier Tuff and San Diego Canyon ignimbrites, Jemez
Mountains, New Mexico: temporal constraints on magmatic evolution: Journal of Volcanology and Geothermal Research, v.
43, p. 175-193.
Timmer, R.S., 1976, Geology and sedimentary copper deposits in the western part of the Jarosa and Seven Springs quadrangles, Rio
Arriba and Sandoval Counties, New Mexico: M.S. thesis, University of New Mexico, Albuquerque, NM , 151 pp.
Woodward, L.A., 1987, Geology and mineral resources of Sierra Nacimiento and vicinity, New Mexico: New Mexico Bureau of Mines
and Mineral Resources, Memoir 42, 84 p.