NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES
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Jemez
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1 MILE
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PONDEROSA
Bear
Springs
Peak
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Contact line is solid where the location is certain and
dashed where approximate
7000 FEET
1 KILOMETER
NEW MEXICO
Cross Section Line
:
Normal fault with bar-ball placed on the downthrown
block. Line is solid where the location is certain, dashed
CONTOUR INTERVAL 20 FEET
San
Ysidro
Jemez
Pueblo
Loma
Creston
QUADRANGLE LOCATION
Magnetic Declination
May 2004
10º 25' East
At Map Center
New Mexico Bureau of Geology and Mineral Resources
Open-File Geologic Map 57
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
[575] 835-5490
Geologic map of the Ponderosa quadrangle,
Sandoval County, New Mexico.
May 2002
by
This and other STATEMAP quadrangles are available
for free download in both PDF and ArcGIS formats at:
G.R. Osburn1,Shari Kelley2, Michael Rampey3,
Charles Ferguson4, Kurt Frankel5,
and Frank Pazzaglia5OO
Earth and Planetary Science Department, Washington University, St. Louis, MO, 63130
2
New Mexico Bureau of Geology and Mineral Resources, 801 Leroy Place, Socorro, NM 87801
3
Queens' College, Cambridge University, CB39ET, UK
4
Arizona Geological Survey, Tucson, AZ, 85701
5
Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, PA, 18015
1
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60
Qp4
Inclined foliation
Vertical foliation
Horizontal strikedip
Qp3
Qp2
Inclined strikedip
Qp1
j
Geomorphic surface
minor fault
Fold line is solid where the location is certain and dashed
where approximate
Qp
F
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NATIONAL GEODETIC VERTICAL DATUM OF 1929
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San Miguel
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(30—45%), flow-banded rhyolite (10—15%), obsidian (0—10%), and pumice (0—10%). In some cases the volcanic
clasts appear to be lithic fragments recycled from the Otowi Member; the pumice and obsidian is also from the
Otowi Member (Scholle and Kelley, 2003). The sandstone clasts are often well-rounded, while the volcanic clasts
are variably angular to well-rounded. Pebble imbrications indicate flow to the south (Scholle and Kelley, 2003).
This unit is stratigraphically equivalent to the Cerro Toledo Interval epiclastic sediment and tephra deposits of
Broxton and Reneau (1995). Ranges in thickness from ~1—6 m.
Landslide deposit—middle Pleistocene to Holocene—Undivided landslide deposits composed of locally derived,
cohesive blocks of Permian, Triassic, and Miocene bedrock, and Bandelier Tuff. The Zia Formation is a common
component of slides on the west side of Borrego Mesa; these slides commonly have reworked El Cajete pumice (Qvec)
on the top surface. Generally associated with a head scarp in their source area. Varies in thickness from ~5—50 m.
Landslide deposit—late Pleistocene—Two landslide deposits just northeast and east of Ponderosa overlie what
appears to be El Cajete pumice. The pumice, which has not been dated at these localities, contains biotite, a
mineral commonly found in El Cajete pumice. Thus, the landslides are likely to be younger than 60 ka. The El
Cajete pumice at UTM coordinates 13S 351329 3950183 (NAD27) on National Forest land, is a weakly- stratified
primary fall deposit that is ~0.6 m thick . In an exposure just to the south, the El Cajete Pumice is overlain by a
fine-grained, ash fall. The material in this slide is different than the debris in the other landslides in the area
because it contains Triassic Chinle at the base, overlain by Jurassic Entrada Sandstone, Jurassic Todilto
e clasts that are likely from the Cerro Conejo
Formation. A second landslide exposure, with Chinle mudstone sliding over El Cajete pumice, which in turn
rests on Chinle mudstone, is at 13S 350758 3948958 (NAD 27) on private land.
Qbo
Terrace deposits—Holocene—Red to tan, fine-grained silt and sand alluvial fill with locally well-rounded
cobbles. Treads are up to ~3 m above modern drainages. Strath is ~1—2 m above active channel. Age of deposit
along the Jemez River is 3160 ± 60 radiocarbon years (LLNL # 24692; Formento-Trigilio, 1997) and 4530 ± 40
radiocarbon years (Beta # 160851) along Vallecito Creek. ~1—5 m thick. Qt6 of Formento-Triglio (1997).
Qgo
Qblc
Terrace deposits—late Pleistocene—Coarse grained gravel and and boulder material interbedded with pebbly
sand. Clasts are composed of 24% Bandelier Tuff, 20% Tertiary volcanics, 14% Banco Bonito (~60 ka) in the Jemez
River valley (Reneau et al., 1996, Formento-Trigilio, 1997). Qt4a of Formento-Trigilio (1997). Strath is ~10 m above
active channel. ~8—10 m thick.
Terrace deposits—middle to late Pleistocene—Alluvial sands and gravels composed of 34% Bandelier Tuff, 20%
Madera Limestone, and 13% Precambrian granite with lesser amounts of Permian sandstone and Tertiary
volcanics in the Jemez River valley. Locally cemented by calcium carbonate. A late Pleistocene/early Holocene
soil is developed in an eolian deposit on the terrace tread that buries a Bk soil horizon with Stage II carbonate
development. ~9 m thick. Highly variable strath topography ranging from 4 to 36 meters above active channel
(Formento-Trigilio, 1997).
anticline
Qtr
monocline
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.
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.
Qfo
QTst
Tpd
Pediment deposits—early to late Pleistocene—Alluvial deposits of various clast compositions relating to source
in ephemeral tributary drainages. Generally composed of cobble to boulder size clasts. Deposits are of variable
thickness and have straths of variable topography that is often obscured by colluvium derived from the
pediment deposit. Treads of deposits are relatively flat and grade back towards mesas.
Pediment deposit—early to middle Pleistocene—Piedmont alluvial deposits found on relatively flat treads
grading back towards mesas. Composed of cobble to boulder size clasts of Triassic and Permian bedrock,
Bandelier Tuff and basalt derived from Borrego Mesa as a function of source area and drainage. Deposit is
~10—15 m thick. Correlative with Qt3 terrace elevations.
Pediment deposit—early to middle Pleistocene—Piedmont alluvial deposits found on relatively flat treads
grading back towards mesas. Composed of cobble to boulder size clasts of Tertiary (Miocene) bedrock and basalt
derived from Borrego Mesa as a function of source area and drainage. Deposit is ~10—15 m thick. Correlative
with Qt2 terrace elevations.
Qvec
Tdf
Tpv
Tai
Tpbb
Tpb
Travertine deposit—Middle to late Pleistocene—Light gray irregularly bedded limestone or travertine. One
travertine deposit overlies pink to tan fluvial sandstones of uncertain age (Arroyo Ojito Formation?) on the
south-dipping Glorieta Sandstone surface east-southeast of Red Rocks. Further south, travertine sits on the
pediment gravel and is reworked into the base of the Qt4 terrace gravel. This relationship suggests that the
travertine is older than 150,000 ± 50,000 years, the estimated age of the Qt4 terrace (Formento-Trigilio and Pazzaglia,
1998) and is younger than the pediment gravel. The elevation of the pediment gravel appears to correspond to
400,000 ± 100,000 year Qp2 (Formento-Trigilio and Pazzaglia, 1998). A second, more extensive travertine deposit is
located north of Vallecitos Creek and rests on Zia Sandstone. A small deposit of banded travertine with alternating,
millimeter scale, white, brown, and gray layers is located east of Ponderosa. 1—3 m thick.
Tccs
Tccd
Tcc
Qbt
Bandelier Tuff , Tshirege Member—early Pleistocene—White to orange to pink non-welded to welded rhyolitic,
ash-flow tuff (ignimbrite). Qbt, which originated from catastrophic eruptions that formed the Valles caldera,
forms conspicuous orange to tan mesa-capping cliffs. The tuff contains abundant phenocrysts of sanidine and
icrophenocrysts of hypersthene and fayalite.
Tz
Ta
Tgc
Paliza Canyon Formation volcaniclastic gravel—Volcaniclastic sediments interbedded with and overlying the
volcanic rocks of Borrego Mesa. Consists of tan to brown sandstones and conglomerates. Contains well-rounded
to subrounded clasts of volcanic rocks, mostly of mafic to intermediate composition. Some rhyolite and obsidian
pebbles and cobbles are locally present, as are thin pumice and ash beds (Tct). 0—70m.
Paliza Canyon Formation andesitic intrusive—Miocene—Light-to dark-gray, fine-grained rock with sparse
plagioclase and pyroxene phenocrysts. Pieces of Canovas Canyon dacite are included in the intrusive along the
margin and the older dacite is altered and iron-stained along the contact.
Tct
Tpcm
Js
Summerville Formation—gray, maroon or pinkish-red siltstone and silty mudstone. Occurs only as small
discontinuous outcrops along Jose fault zone west of Borrego Mesa.
Jt
Je
Todilto Formation—Brown to gray laminated, fetid limestone (Luciano Mesa Member) overlain by white
gypsum (Tonque Arroyo Member). The Todilto Formation crops out in Paliza Canyon northeast of
Ponderosa. The base is poorly exposed due to mass wasting, but limestone float can be observed. The top is
not exposed because it is covered by a landslide. Elsewhere, the Todilto Formation is present as
discontinuous outcrops in the Jose fault zone. Maximum thickness 25 m
Entrada Sandstone—White to yellow to red, fine- to medium-grained, well-sorted, well-rounded, cross-bedded
exposed. Cross-beds dip to the west. In the Jose fault zone, discontinuous exposures of the Entrada Sandstone
are locally mapped with the overlying Todilto Formation (Jet). Maximum exposed thickness 25 m.
Triassic Sedimentary Rocks
@c
@cs
@ml
Petrified Forest Formation (Chinle Group)—Principally red mudstones with minor thin, tan thin-bedded,
ripple-laminated to cross-laminated micaceous sandstones. Locally the mudstones may be black, purple,
dark blue, especially near the lower contact. Interbedded sandstones are particularly common and persistent
in the approximate stratigraphic position of the Poleo Sandstone and overlying Mesa Montosa Sandstone.
These sandstones are particularly thick and persistent in two locations in Cañon de Cañada (approximately
39°49.5' and 39°55.4') and were mapped as TRcp. Elsewhere, near Ponderosa, strike and dip symbols mark
the position of the < 5 m thick Poleo and Mesa Montosa sandstones.
sandstone is usually cross-stratified, often in trough geometries, and it is well cemented, making the unit a
consistent ridge former. Coarse conglomerate beds, up to several m thick, containing siliceous pebbles and cobbles
up to 15 cm, are common near the base. Clasts are predominantly
rip-up clasts and petrified wood. Conglomerates often cemented with dark brown ferruginous material. Upper
contact is mapped at upward increase in shale content. This increase is often abrupt and the overlying shale is
often purple, black or dark blue, suggestive of Salitral Formation. In other places the contact is gradational into
thin-bedded, ripple- and cross-laminated sandstones in the overlying Chinle Group. 30—60 m thick.
Moenkopi Formation—Dark chocolate brown to reddish brown micaceous shale, silty shale and thin-bedded
feldspathic sandstone. The proportion of shale and sandstone varies laterally, and in sand rich areas, the
sandstones are medium-bedded. Underlain by a sharp contact with the white Permian Glorieta Sandstone.
Overlain in sharp contact by the contrasting light-colored sands of the Shinarump Conglomerate. The Moenkopi
Formation in the Red Rocks area is unique in that it contains a ~1 m thick layer of fossiliferous sandy limestone
(TRml). Poorly preserved pelecypod fossils (unoids) are concentrated near the base of the limestone. In most
exposures of the Moenkopi Formation on the ridge east of Red Rocks, the limestone is the topmost unit; however
at one locality (13 S 345037 3945145), the limestone is capped by a cross-bedded red sandstone. Thickness varies
from 6—12 m laterally perhaps due to erosion of upper beds beneath the Shinarump Conglomerate.
Permian Sedimentary Rocks
Pg
Py
Canovas Canyon sediments—Miocene—Localized deposit of volcaniclastic fluvial sandstone and conglomerate
that appears to have been deposited at the same time as the Chamisa Mesa Member of the Zia Formation. This
deposit lies northwest of the rhyolite/dacite intrusion, sits on the Jurassic Entrada Sandstone, and is capped by
thin Paliza Canyon Formation volcaniclastic sediments (< 5 m, too small to show on the map) and rockslide
debris. The basal part of the exposure is poorly indurated fine-grained, well-sorted sandstone with angular
grains interbedded with very fine-grained sandstone. This 3 m thick deposit is overlain by well-cemented
sandstone and conglomerate. The fine- to medium- grained sandstone has cross-bedding (low angle); the sand
grains are well-rounded and moderately sorted. The clasts in the conglomeratic intervals are aphyric pumice and
vesicular clasts of dacite with hornblende and biotite. Approximately 12 m thick
Pa
dacite with feldspar phenocrysts. The dacite grades into pink to reddish brown flow-banded rhyolite (Tcc),
which forms the notable knob east of Ponderosa. The crystal-poor rhyolite contains biotite, feldspar, and small
Canovas Canyon ignimbrite and tephra—Miocene—White to pink pyroclastic flows and ash fall deposits. Two
tuff beds are exposed on Borrego Mesa between the upper olivine basalt and the lower Chamisa Mesa basalt. The
upper tuff is pink and massive with about 10% lithics of flow-banded rhyolite and obsidian. The pumice is
aphyric. The lower tuff is pink and massive with about 15% lithics of flow-banded rhyolite and obsidian. The
Basalt of Chamisa Mesa—Miocene—Basalt with well-developed interstitial texture. Dark gray to black, aphyric
to phenochyst poor basalt with rare phenocrysts of olivine and plagioclase. Two basalt flows low in the sequence
yield 40Ar/39Ar ages of 9.44 ± 0.45 and 9.37 ± 0.28 Ma. Chamberlin and McIntosh (2007) determined an average
40Ar/39Ar age of 9.9 ± 0.9 Ma for this flow based on two samples from the Loma Creston quadrangle to the
southwest. Thickness probably 5—10 m.
Gilman Conglomerate—Greenish gray, matrix-supported, pebble to cobble conglomerate. This conglomerate
contains cobbles of intermediate composition volcanic rock, gr
material is concentrated at the base and at the top of the unit. Most of the clasts are dacitic to andesitic
volcanics and dacitic intrusive rocks from an uncertain source and are <15—20 cm in diameter. Rare clasts
/39Ar ages (Kelley et al., 2007). The Gilman
Conglomerate in the southwestern Jemez Mountains is ~60 m thick west of Cañon, and is ~57 m thick at
Gilman. The conglomerate thins abruptly to the north and east and is generally represented by fluvial and
debris flow deposits < 2 m thick that contain only Proterozoic g
clasts and local 1 m thick carbonate cemented sandstone beds. Preliminary analysis of paleocurrent direction
recorded by imbricated cobbles in the volcaniclastic conglomerate near Cañon indicates flow toward the
northwest. The paleocurrent data and the decrease in thickness toward the north suggest a volcanic source to
the south (Connell et al., 2007; Kelley et al., 2007).
Morrison Formation—yellowish to tan, iron-stained subarkosic to arkosic sandstones. Occurs only as small
discontinuous outcrops along the Jose fault zone west of Borrego Mesa.
Paliza Canyon Formation basalt—Miocene—Medium to dark gray porphyry with 15—20 % phenocrysts of
plagioclase and < 3% pyroxene. Underlies the olivine-rich b
volcaniclastic sediments. 3—5 m thick.
Chamisa Mesa has two cycles of graded bedding and the pumice contains phenocrysts of biotite. Thin beds of
tephra are interlayered in volcaniclastic sandstone, conglomerates and basalt on the west side of Borrego Mesa.
Individual tuff beds are 3—4 m thick, and the tephra beds are 0.5—2 m thick.
Abiquiu Formation—White to tan, fine-grained sandstone that is alternately well-cemented and poorly
cemented intercalated with very- fine-grained, white ash fall deposits. Contorted bedding caused by soft
sediment deformation and cross-bedding is rare and is restricted to the top of the unit. The sand grains are
angular and well sorted. The exposure north of Cañon del Raphael Gallegos includes thin red siltstone and
shale beds. The tops of tabular beds in the upper Abiquiu Formation in northern Cañon de la Cañada are red
and are laced with fine root casts. A biotite-rich ash bed from the upper Abiquiu Formation in Cañon de la
Cañada yields a 40Ar/39Ar age of 20.61 ± 0.07 Ma, in the range of 17—25 Ma determined for equivalent strata
to the north near Cerro Pedernal (Smith et al., 2002).
Jm
moderately porphyritic with phenocrysts of plagioclase, olivine and pyroxene. Phenocryst content is typically <
10% with olivine commonly altered to reddish-brown iddingsite. Chamberlin and McIntosh (2007) determined
an average age of 9.14 ± 0.12 Ma from four samples of this widespread basalt on the Loma Creston quadrangle to
the southwest. 5—10m thick.
Canovas Canyon dacite/rhyolite intrusion and flow—Miocene—Small plug and associated flow of dacitic to
Zia Formation undivided—lower-middle Miocene: includes the Chamisa Mesa Member (middle
Miocene)—Tan to white, massive tabular and cross-stratified sandstone interbedded with thin beds of red
mudstone form the lower two thirds of Borrego Mesa. The cross-beds are generally low-angle; high angle
crossbeds are less common. Ripple marks and burrowed horizons are present but rare. The sandstone is
generally weakly indurated except in the vicinity of faults. Popcorn sandstone concretions near fault zones
are common. The fine to medium sand grains are variably well-rounded to angular and are well to
moderately sorted. Root casts are present in the more massive beds. 100 m thick.
Piedra Parada Member (lower-middle Miocene)—whitish-gray to pinkish-gray cross-stratified sandstone,
cross-beds are meter scale, sand grains are rounded and well sorted. Eolian in origin; derived from sources to
the west. This member of the Zia Formation forms the prominent white outcrops in the Red Rocks area in the
southwest corner of the map; 30 m thick.
Jurassic beds crop out only on the steep slopes of Borrego Mesa where they are largely buried by mass wastage deposits
of various types. Exposures are discontinuous and poor. The situation is further complicated by structural disruption.
Debris flow deposit—Pliocene—A reddish to yellowish tan, matrix-supported sandy debris flow resting on
angular, brecciated blocks of Paliza Canyon Formation andesite. This discontinuous deposit overlies Permian
Abo Sandstone and lies beneath Tog on the west side of Cañon de San Diego near the northern quadrangle
boundary. This unit is likely a southward continuation of the debris avalanche deposit exposed between La
Cueva and Jemez Springs, as described by Kelley et al. (2007). Maximum exposed thickness 1—2 m.
Paliza Canyon Formation dacite—Dark gray, dense lava containing a few percent plagioclase phenocrysts and
sparse but distinctive acicular hornblende phenocrysts. Lava forms mesa cap and small knobs on northern extent
of Borrego Mesa on this map and several of the large coherent masses mapped as rock slide deposits on the mesa
slopes. Gardner (1985) determined the geochemistry of this flow, which plots in the trachydacite field.
Cerro Conejo Formation of the Santa Fe Group—Likely forms the slopes of Borego Mesa, but is poorly exposed.
Jurassic Sedimentary Rocks
of the rhyolite flow on the east side of the knob. 40Ar/39Ar ages of 9.37 ± 0.16 and 9.41 ± 0.24 Ma were
determined for the intrusion and glassy margin, respectively.
El Cajete pumice (El Cajete Member of Valles Rhyolite)—middle to late Pleistocene—White to tan, moderately
plagioclase with rare microphenocrysts of hornblende and clinopyroxene; Qec originated north of map area from
E1 Cajete crater in southern moat of Valles caldera (Bailey et al., 1969; Smith et al., 1970; Gardner et al., 1986; Self
et al., 1988; Wolff and Gardner, 1995); unit dated at about 50—60 ka (Toyoda et al., 1995; Reneau et al., 1996).
Maximum exposed thickness about 10 m in northeast part of map area, where the unit forms extensive mesa top
cover on San Juan Mesa. Primary fall deposits that are 1—2 m thick are locally preserved under landslides and
colluvium northeast and northwest of Ponderosa. In the eastern and southeastern parts of the map area, the El
Cajete pumice is thin (~15 cm) and has been fluvially reworked.
Tson
Sinter deposit—Pleistocene—Miocene—Chalcedony and opal cementing Zia Formation sandstone and Entrada
Sandstone along the Jose fault zone. Outcrop is about 10 m wide.
Keres Group Volcanic and Vocaniclastic Sedimentary Rocks (Miocene)
Pediment deposit—early to late Pleistocene—Undivided piedmont alluvium found on relatively flat treads
grading back towards mesas. Composed of cobble to boulder size clasts of Bandelier Tuff, Triassic and Permian
bedrock, and basalt as a function of source area and drainage. Ranges in thickness from ~5—15 m.
Quaternary Volcanic and Volcaniclastic Sedimentary Rocks (Tewa Group)
~9.4 Ma Chamisa Mesa basalt on Borrego Mesa. May correlate to the Navajo Draw Member, but has a Sierra
Nacimiento provenance. 10 m thick.
@m
Pediment deposit—early to middle Pleistocene—Piedmont alluvial deposits found on relatively flat treads
grading back towards mesas. Composed of cobble to boulder size clasts of basalt derived from Borrego Mesa.
Deposit is ~5—10 m thick. Correlative with Qt1 terrace elevations.
Old Alluvial Fan—middle to late Pleistocene (?)—Old, inactive alluvial fans perched at positions in landscape
above modern streams. The fan is composed of generally stratified silt to boulder size alluvium containing clasts
of rounded Abo and Yeso sandstone, with some Bandelier Tuff, especially near the base of the deposit,
Old fluvial gravel—late Pliocene (?)—Alluvial to fluvial gravel and sandstone deposits underlying the La Cueva
Member or the Otowi Member of the Bandelier Tuff. Clasts are generally sub-rounded to well rounded, and are
pebble to boulder size. Clasts are in a silty to medium sand size matrix or are clast supported. Sand grains in
matrix are angular and poorly sorted. Gravel is usually present at the base of the deposit and red-brown
fine-grained sandstone is present at the top. The sandstone locally contains abundant pumice clasts from early
tephra eruptions that occurred prior to the eruption of La Cueva Member. The gravel clasts are composed
predominantly of Paliza Canyon Formation andesite, dacite, and basalt and Permian sandstone, with occasional
Formation sandstone, Pedernal chert, and obsidian (Kelley and Scholle, 2003). The gravels are well exposed on
the east side of Virgin Mesa and in Virgin Canyon, but they are not shown on the map because they are in a cliff.
These gravels are common beneath the Otowi Member on the northwest side of Paliza Canyon. These deposits
could be equivalent to gravels of the Quaternary/Tertiary Cochiti Formation (Smith and Lavine, 1996), which
contains predominantly rounded, volcanic clasts. Varies in thickness from ~1—12 m.
locally overlain by Bandelier Tuff colluvium. ~ 5 - 10 m in thickness.
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.
QTgo
Terrace deposit—middle Pleistocene—Coarse sand and gravel interbedded with fine-grained silt and sand.
Deposit is ~14 m thick Gravels are composed of 27% Madera Limestone, 27% Bandelier Tuff, and 23%
Pediment deposit—middle to late Pleistocene—Piedmont alluvial deposits found on relatively flat treads
grading back towards mesas. Composed of cobble to boulder size clasts of Triassic bedrock, Bandelier Tuff, and
basalt from Borrego Mesa as a function of source area and drainage. Deposit is ~5—10 m thick. Correlative with
Qt4 terrace elevations.
La Cueva Member—early Pleistocene—Not shown on map, but exposed in cliff walls in Cañon de San Diego east
of Virgin Mesa down to the southern end of Virgin Mesa. Gray to white, nonwelded to poorly welded ash flow
oxene and magnetite. The deposit consists of
two units (Tuberville and Self, 1988). The lower unit (A) is nonwelded and is comprised of abundant lithic
fragments. The lithic fragments are dominantly basalt and andesite from the underlying Paliza Canyon Formation,
with minor Proterozoic plutonic and metamorphic components (Tuberville and Self, 1988). The maximum size of
the lithic fragments is 25 cm (Tuberville and Self, 1988). The upper unit (B) is nonwelded to slightly welded and
contains large pumice clasts characterized by vesicles with high aspect ratios. A third unit not previously
recognized is present near the northern boundary of the quadrangle on the west wall of Cañon de San Diego.
Locally, the units are separated by fluvial gravels and mudstones, but the sedimentary packages are too thin (< 2
m) and too discontinuous to show on the map. Clasts in the gravel include Paliza Canyon Formation andesite,
dacite, and basalt, Permian (Glorieta, Yeso, Abo) sandstone, eroded La Cueva Member, flow-banded rhyolite,
Arroyo Ojito Formation of the Santa Fe Group (Navajo Draw Member)—Poorly exposed tan sandstone with
underlies Quaternary travertine and rests on Permian Glorieta Sandstone at 13 S 344461 3944802 (NAD27). A
second deposit of pinkish-tan conglomeratic sandstone and conglomerate containing rounded red granite,
Fluvial gravel and sandstone—early Pleistocene—Not shown on map, but exposed in cliff walls of Cañon de San
Diego east of Virgin Mesa. Tan fluvial sandstone and gravel deposit between the Otowi Member and the La
Cueva Member of the Bandelier Tuff. The gravel is mainly composed of imbricated Paliza Canyon Formation
andesite, basalt, and dacite boulders and pebbles (~60%; Scholle and Kelley, 2003). Other clasts include
Proterozoic granite (0—5%), Permian sandstone (5—20%), Pedernal chert (0—5%), and eroded La Cueva
Member and pumice (5—10%). Maximum of 4 m thick.
rounded to angular, and are pebble to boulder size. One of the best exposures of fluvial gravel between the units is
located near the northern edge of the quadrangle on the west side of Cañon de San Diego. The tuff is underlain by
a Pliocene(?) debris flow in the northern part of the area and by Tog at the south end of Virgin Mesa. Spell et al.
(1996) calculated a 40Ar/39Ar age of 1.85 ± 0.07 Ma for the tuff. Thickness ranges from 2—20 m.
Terrace deposits—middle Pleistocene—Coarse-grained sand and gravel interbedded with fine-grained,
cross-bedded, sand and silt. Deposit is ~13 m thick. Gravels are composed of 32% Bandelier Tuff, 17% Madera
Limestone, 19% Precambrian granite and lesser amounts of Permo-Triassic sandstones in the Jemez River valley.
Strath is characterized by up to 1 m of relief and ranges from 61 to 84 m above active channel. Tread exhibits an
incomplete K soil horizon with Stage III+ carbonate development. (Formento-Trigilio, 1997).
Pediment deposit—middle to late Pleistocene—Piedmont alluvial deposits found on relatively flat treads grading
back towards mesas. Composed of cobble to boulder size clasts of Triassic bedrock and basalt from Borrego Mesa
as a function of source area and drainage. Deposit is ~5—10 m thick. Correlative with Qt5 terrace elevations.
Tscc
Maximum exposed thickness about 100 m.
Terrace deposits—Holocene—Fine grained, red to tan alluvial silt and sand alluvial fill. Strath is < 8 m above
active channel. Qt5 of Formento-Trigilio (1997). ~1—5 m thick.
Terrace deposits—late to middle Pleistocene—Coarse, stratified, sandy gravel deposit composed of 41%
Bandelier Tuff, 17% Madera Limestone, 17% Precambrian granite and lesser amounts of Permo-Triassic
sandstone in the Jemez River valley. Strath exhibits up to 1 m of relief and ranges from 30 to 63 m above modern
channel. ~10 m in thickness. An Ochric A soil horizon overlies a Bk soil horizon with Stage II—III carbonate
development beneath the tread. (Formento-Trigilio, 1997).
Bandelier Tuff, Otowi Member—early Pleistocene—White to pale pink, unwelded, weakly indurated rhyolitic
ash-flow tuff that contains abundant (10—20%) accidental lithic fragments. Qbo, which originated from
catastrophic eruptions that formed the Toledo caldera, forms conspicuous white cliffs or white slopes below Qbt.
Qbo discontinuously fills in rugged topography that developed on a pre-Toledo caldera age volcanic surface and
can form spectacular tent rocks; upper surface quite undulatory due to erosion. Phenocrysts of sanidine and
stratified pumice fall and surge deposit at base of unit (Guaje Pumice Bed) is generally not found in this area; in
places (e.g., Cañon del Raphael Gallegos area) the pumice is <0.5 m thick. The top of the Otowi Member is
vapor-phase altered and has a vapor-phase notch in San Juan Canyon in the northeastern corner of the
quadrangle. The Otowi Member is difficult to distinguish from the Tshirege Member in hand sample. The Otowi
Member is characterized by a poorer degree of welding, a greater tendency to form slopes instead of cliffs, more
abundant lithic fragments, less abundant iridescent sanidine, and stratigraphic position beneath the Tsankawi
Andesite rockslide deposit—middle Pleistocene to Holocene—Rockslide composed of cobble to house size clasts
of andesite. Generally related to a prominent head scarp along the west side of Borrego Mesa. Poorly stratified.
Generally 5—50 m thick.
Terrace deposits—middle Pleistocene to Holocene—Alluvial silt, sand, cobble, and boulder deposits of volcanic,
sandstone, and granitic provenance overlying distinct straths and underlying discrete treads related to the large
modern drainages of the Jemez River and Vallecito Creek. Commonly exhibits a coarse, fine, coarse alternating
Pleistocene stratigraphy.
Virgin Mesa Member, Cerro Toledo Formation—early Pleistocene—Not shown on map, but exposed in cliff
walls in Virgin Canyon and Cañon de San Diego east and west of Virgin Mesa. This gravel is also exposed on the
west side of Mesa de Guadalupe. Fluvial gravel and sandstone deposits underlying the Tsankawi Pumice Bed of
the Tshirege Member of the Bandelier Tuff and overlying the Otowi Member of the Bandelier Tuff. At southern
tip of Mesa de Guadalupe, this gravel lies beneath the Tshirege Member of the Bandelier Tuff and contains
rounded pieces of lithic-rich tuff interpreted to be the Otowi Member of the Bandelier Tuff. Clasts from the west
Tertiary Sedimentary Rocks
Madera Limestone (0—5%), Permian (Abo, Yeso, Glorieta) sandstone (0—15%), Paliza Canyon Formation
andesite, dacite, and basalt (10—45%), flow-banded rhyolite (0—5%), Pedernal chert (0—5%), and lithic-rich tuff
(5—50%). The Proterozoic component of the gravel is as high as 70% on the west side of Mesa de Guadalupe and
drops off to 1% toward the south and east (Scholle and Kelley, 2003). Much of this material is derived from
erosion of the Sierra Nacimiento to the west. Clasts in the Cañon del Raphael Gallegos area include Proterozoic
Bandelier Tuff colluvium and related hillslope deposits—middle Pleistocene to Holocene (?)—Hillslope colluvial
deposits composed of pebble to boulder size clasts of Bandelier Tuff derived from mesa cap rocks. Poorly sorted
and poorly stratified. Matrix and clast supported. Significant accumulations found in Cañon de San Diego,
Cañon de la Canada, San Juan Canyon, and Paliza Canyon. Generally from ~5—50 m thick.
Locally cemented by calcium carbonate. Reworked Lava Creek B ash (640 ka; Dethier, 2001) is locally present in
fine-grained layers. Tread exhibits an incomplete K soil horizon with Stage III+ carbonate development. Strath
ranges from 83—100 m above modern channel (Formento-Trigilio, 1997).
EXPLANATION OF SYMBOLS
0.5
Qcvm
Colluvium, talus and related hillslope deposits—Undivided hillslope deposits consisting of locally derived
pebbly to boulder size clasts with or without finer matrix. May be clast or matrix supported. In general, mapped
only where underlying bedrock contacts were obscured. Extensively subdivided by Frankel and Pazzaglia
(2002). Generally 1—50m thick.
Tpcm
Base map from U.S. Geological Survey 1970, from photographs taken 1965, field checked in 1970, edited in 1993.
1927 North American datum, UTM projection -- zone 13N
1000-meter Universal Transverse Mercator grid, zone 13, shown in blue
1
Upland alluvium, colluvium, and eolian deposits, undivided—Holocene to upper Pleistocene (?)—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 where other alluvial units are not mapped. Generally < 10 m thick.
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The sanidine typically displays blue iridescence. A thin (<2 m) laminated, pumice fall and surge deposit
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unit. The tuff consists of multiple flow units in a compound cooling unit (Smith and Bailey, 1966; Broxton and
Reneau, 1995). Cooling units that likely correlate to units 1g, 1v, 2, and 3 on the Pajarito Plateau (Broxton and
Reneau, 1995) are present on the tuff-capped mesas on the quadrangle. Welded unit 2 forms the pronounced
dark gray band in the tuff cliffs of San Juan Canyon and Cañon de San Diego. The white tuff (unit 3?) on top of
the mesas in the northern part of the Ponderosa quadrangle contains 5—10% accidental lithic fragments of older
country rock entrained during venting and pyroclastic flow. 40Ar/39Ar age is 1.25 ± 0.01 Ma (Phillips, 2004).
Maximum observed thickness ~140 m.
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silt and clay. Poorly stratified. 1—10 m thick. One is dated at 1660 ± 70 radiocarbon years BP (Beta # 85445;
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Qfy
Pa
:
10
Py
10
Qc
Py
Pa
Qc
3
Qc
o
o
30
s
o
m
Qcbt
13
Qt7
348000
Qfo Qc
Pa
Qc
oo
Qc
QTgo
Ta
s
347000
Qfo
Pg
s
Qc
346000
Qcbt
m
3957000
106°42'30"W
345000
:
344000
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343000
o
342000
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106°45'0"W
NMBGMR Open-file Geologic Map 57
Last Modified January 2012
A DIVISION OF NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY
edding varies from massive to planar to
cross stratified. Sandstones are typically well sorted. Feldspathic red sandstones and some shale interbedded
in subordinate amounts. 15 m thick.
traditionally been divided into two members in the southwestern Jemez Mountain region, the lower Meseta
Blanca Member and the upper San Ysidro Member (Wood and Northrop, 1946; Stanesco, 1991; Mack and
Dinterman, 2002). Lucas et al (2005), following the work of Baars (1962), applied the name De Chelly
Sandstone to the Meseta Blanca Member and elevated the Yeso Formation to group status. In the Red Rocks
area on Jemez Pueblo, the basal part of the De Chelley Sandstone consists of thinly bedded, orange sandstone
that is cross-bedded with low angle to subhorizontal stratification. The basal unit pinches out north of Red
Rocks. This unit is overlain by a reddish-orange, medium to thick-bedded tabular sandstone with thin shale
interbeds, occasional fluvial channel structures, and rare mudcracks. This package of tabular sandstone
thickens to the north of Red Rocks. The upper part of the De Chelly Sandstone is characterized by a
distinctive eolian depsoit with meter-scale, tabular-planar, wedge-planar and trough cross-beds that record a
paleo-transport direction generally to the south (Stanesco, 1991). This sandstone contains a thin (0.1—0.3 m
thick), discontinuous pedogenic carbonate horizon that is present in the cliffs just the contact with the San
Ysidro member. The San Ysidro Member of the Yeso Formation is primarily medium-bedded, tabular
sandstone that is orange red near the base and red near the top. A continuous (1—2 m thick) limestone bed is
present near the top of the unit. The sandstone under the limestone is altered and bleached due to weathering
of the sandstone prior to the deposition of the limestone. The limestone exhibits soft-sediment deformation
and fills in low spots in the underlying sandstone. The contact of the Yeso Group with the overlying Glorieta
Sandstone is mapped at the transition to predominantly mediu
sandstone. The Yeso Group is 170 m thick in Cañon de San Diego (Stanesco, 1991) and is 156 m at Red Rocks.
Abo Formation—Red to dark red, medium- and thin-bedded arkose or feldspathic, medium- to
coarse-grained, fluvial channel sandstones, intraformational conglomerates, and fine-grained overbank
deposit mudstones and shales. Green reduction spots and layers are common. The sandstones are
cross-stratified (typically trough and wedge-planar geometries) and the finer grained rocks commonly have
ripple cross-laminations. Mud-chip clasts and plant debris are common. Base is not exposed in map area.
Upper contact with Yeso Formation mapped at abrupt change from medium-grained to coarse-grained
s. The contact between the Abo Formation
and the overlying Yeso Formation is usually conformable (Woodward, 1987; Stanesco, 1991). Lucas et al.
(2005) measured 492 ft (150 m) of Abo Formation, (base not exposed, but measured up to the Yeso Formation)
south of Jemez Springs on the Ponderosa 7.5’ quadrangle.
Pennsylvanian Sedimentary Rocks
&m
&s
Madera Formation—Light-gray, fossiliferous limestone, white
arkose, light-gray shale with subordinate arkosic limestone. Overlies Sandia Formation. Upper contact not
observed in this map area. Maximum exposed thickness 15 m.
sandstones interbedded with brown, red,
green or gray shale and thin-bedded fossiliferous limestone. Minor arkosic sandstones also present. Base not
exposed in this map area. Contact with overlying Madera Formation mapped at abrupt increase in
proportion of limestone beds. Maximum exposed thickness 10 m.