105°45'0"W
433000
434000
435000
436000
105°42'30"W
437000
438000
105°40'0"W
439000
440000
441000
442000
105°37'30"W
443000
444000
4012000
4012000
D'
68
Qqg
Xhpl
Xhow
Qal
Xhp
4011000
Xhr6
Xhr4
Xhr3q
Qqg/Tpl
Xho
Xhr3
ticline
Xhu
81
o
lom
60
61
Xho3
P
Xhp
Fa
ult
Xvf
Xvf
62
Xvm
Qg
Xgp
Xvs
Xvm2
Qg
Qg
Qal
Qg
Xgp
10
Qg
5
Tpm
Qg
36°12'30"N
Qg
Xvu
87
Xvs
Xvs
Qg
Qto
Xva
72
Qg
Qto
Qfy
Qty
Qto
4006000
Qty
Ypqm
Qto
Qto
Qto
F
Qto
11
Tb
Qfy
Qto21
Xva
a
en
s
co
H
st
Xvu
Qg
Qfy
5
Qto
Tpm
Ypqm
Qto
Tpm
QTg
107
8
XvcamQfy
5
Qfy
6
Qty
Tpmc
30
Qal
Qfy
12
15
Td
12
Tpu
Qg Qg
11
8
Ypqm
8
8
4
Qto
Tpm
Tpmc(?)
Qfy
I
Qto
QTg
Qfy
Qfy
Tpu
Qlb
Tb
17
Tb
4005000
10
Qlb
8510
801
25
Tpmc 22
Qty Qfy
29
Qty
Qfo
Qto
Qto
25
Tpu
Qto
Qfy
Qto
Qty
Qfy
Qto
QTg
Qlb
Qfy
Qty
Tpu
15
Tpmc
Tpu
Qto
4004000
Qto Qfy Qty
Qto
6
4003000
Tpmc
Td
QTg
9
Qfy
4002000
6
3
Qfy
QTg
20
QTg
4001000
Td
5
Qfy
Qty
Qfo
Qfy
Qty
Qfy
QTg
4
Td
Qfy
QTg
5
QTg
E'
Qfy
5
Qty
3
QTg
Qty
QTg
crossbedded, and generally contains a well-developed extension lineation defined by kyanite. Thickness is approximately 200 m.
Ortega Formation laminated schist-Southwest of the Pilar-Vadito fault. Reddish to orange-brown to white quartz-muscovite schist containing
Xho1
EARLY PROTEROZOIC VADITO GROUP
Transitional Vadito Group-Hondo Group rocks-North-central map area on east side of Picuris Canyon. Includes a variety of rock types
Xvht
intermediate in mineralogy and texture between the metavolcanic rocks of the Vadito Group and metasedimentary rocks of the Hondo Group.
Conglomeratic schistose quartzite, white quartz-muscovite feldspathic schist, gray quartzite and metaconglomerate, conglomeratic quartzite
and schistose quartzite with clasts of bull quartz, quartzite, and fine-grained black rock, schistose metaconglomerate, and quartz-eye
conglomerate. Gradational eastward along strike with feldspathic schists (Vvf) of the Vadito Group. Might be equivalent to part of transitional
section south of Kiowa Mountain in the Tusas Mountains (Bauer and Williams, 1989), however, in this map area VHt has been disrupted by
Rio Pueblo schist-East of the Picuris-Pecos fault only. Well-bedded, white, gray, and pink feldspathic quartz-muscovite quartz-eye schist.
Locally composed of up to 40% coarse white muscovite flakes in a matrix of granular quartz and feldspar. Quartz-eyes are abundant and
consistently flattened in the dominant foliation plane. Along the northern contact the Miranda granite intrudes and crosscuts layering in the
schists. Along the southern contact with a massive gray quartzite, a Mn-rich horizon occurs stratigraphically below the quartzite, and
piemontite and altered porphyroblasts that might be pseudomorphs after Mn-andalusite are found along the schist-quartzite contact. This
mineralized horizon is similar to that exposed in the Glenwoody Formation of the Pilar cliffs in the Carson and Trampas quadrangles.
Ma in Trampas quadrangle (Bell, 1985).
plagioclase-muscovite-biotite-opaque slightly schistose units with polycrystalline quartz eyes (2-8mm). Eyes are slightly flattened in foliation,
fine- to medium-grained matrix of plagioclase, K-feldspar, biotite, and muscovite. Accessory minerals are epidote, allanite, sphene, and zircon.
and probably represent relict phenocrysts in felsic volcanic rock. Trace minerals include sphene, apatite, monazite, zircon, and tourmaline.
Pervasive, moderately to well-developed foliation is parallel to regional foliation. U-Pb zircon isotopic age of 1684 Ma (Bell, 1985) in the
Xg
Trampas quadrangle. Exposed only in southwestern corner of map area.
Finer-grained felsic rocks are similar in mineralogy to coarser units, but lack the abundant quartz eyes. Small red idioblastic garnets are rare.
Picuris Pueblo granite (informal name)-West side of the Picuris-Pecos fault. Medium- to coarse-grained granitic rocks which show a variety
appear to be intrusive into Vadito Group schists. Includes some intermediate(?) feldspathic schists in the Picuris Canyon area.
Small lensoidal bodies of tan to orange-red, garnet-bearing, quartz-muscovite-opaque schist are found locally. Many of the felsic schist bodies
of local textures ranging from coarse-grained, pink feldspar-rich rock to white, quartz-rich rock. In thin section, these rocks show interlocking
Marqueñas Formation, undivided-Fine- to medium-grained, grayish, texturally immature, schistose quartzite. Crossbeds are small-scale
Xvm
mosaics of microcline, plagioclase, quartz, biotite, and iron-oxide minerals. Most samples exhibit considerable alteration of feldspars and
features defined by black mineral laminae. Also includes a variety of metaconglomerates containing dominantly rounded quartzose clasts in a
mica. These granitic rocks are intimately interlayered with supracrustal Vadito Group country rock. Blocks of orthoquartzite within the plutonic
quartz-mica matrix. The Marqueñas Formation may be equivalent to the Big Rock Formation of the Vadito Group in the Tusas Mountains.
rock strongly suggest an intrusive relationship between the two. Contacts between granitic rock and supracrustal rock invariably trend east,
parallel to bedding in the country rock. This name supersedes the informally named Granite of Picuris Peak of Bauer (1988). Age unknown,
Marqueñas Formation northern metaconglomerate-Predominantly composed of flattened quartzite pods. Micaceous quartzite matrix
Xvm3
but texturally similar to ca. 1680 Ma granitoids of the western Picuris Range.
contains scattered clasts, up to 10 cm long, of metasedimentary quartzite (66%), felsic schist (34%), and traces of vein quartz. Alternating
lithologic layers that might indicate original bedding are absent. This unit was described as a flaser-bedded quartzite in the Trampas
Miranda granite (informal name)-Northeastern map area, east of the Picuris-Pecos fault. Generally consists of pink to white, medium-
Xm
quadrangle (Nielsen and Scott, 1979). However, it is probably a sheared, originally thinly bedded pebbly quartzite (Holcombe and Callender,
grained, mica-rich granitic rock with euhedral megacrysts of feldspar. These granitic rocks are everywhere weathered looking, fairly
1982). Gradational with Marquenas Formation quartzite to the south.
equigranular, and commonly crumbly. In places, this rock could be mistaken for an arkose. Appears to intrude the Rio Pueblo schist along
southern contact. Pegmatites are locally voluminous. Contains at least one tectonic foliation. Three closely-spaced, orthogonal joint sets
Marqueñas Formation quartzite-Fine- to medium-grained, grayish, texturally immature, schistose quartzite. Abundant crossbeds ranging
Xvm2
cause this rock to weather into small, angular blocks. This name supersedes the informally named Granite of Alamo Canyon of Bauer (1988).
from small-scale features defined by black mineral laminae to large festoons with cross laminations several cm thick. Crossbeds consistently
Age unknown, but similar in occurrence and texture to Tres Piedras Granite of east-central Tusas Mountains.
young to the north. Pebble-rich layers also define bedding. Contacts with adjacent metaconglomerates are gradational.
EARLY PROTEROZOIC HONDO GROUP
Marqueñas Formation southern metaconglomerate-Polymicitc metaconglomerate containing rounded clasts of quartzite (54%), silicic
Xvm1
metavolcanic rock and quartz-muscovite schist (40%), and white vein quartz in a muscovite quartzite matrix. Clasts are flattened and
Piedra Lumbre Formation-Small exposure in northwest corner of map. Includes quartz-muscovite-biotite-garnet-staurolite phyllitic schist and
Xhpl
constricted in the dominant foliation; aspect ratios average 1:2:3 to 1:2:6, with extremes of 1:2:16 or greater. Matrix averages about 30% of
finely laminated light gray phyllitic quartz-muscovite-biotite-garnet schist and darker bluish gray fine-grained biotite quartzite to metasiltstone.
volume of rock. Minor phases in matrix include ilmenite, biotite, magnetite, hematite, zircon, and tourmaline.
Calc-silicate layers exist locally. Original sedimentary structures such as crossbedding and graded bedding are locally preserved. Welldeveloped cleavage parallel to both layering and axial surfaces of small intrafolial isoclinal folds. Dominant layering in much of this unit is
schistose to gneissic to amphibolitic rocks.
Pilar Formation-Exposed only in northwest corner of map and as fault-bounded sliver in section 14 of northwestern map area. Dark gray to
Xhp
Mixed metavolcanic rocks-In the northern map area, north of Picuris Pueblo. Includes a variety of interbedded mafic to intermediate,
Xvmix
transpositional.
Schists, undivided-Includes a variety of pelitic to semi-pelitic schists. Relatively massive, light gray, fine-grained quartz-muscovite schist with
Xvs
black, carbonaceous phyllitic slates. Extremely fine-grained homogeneous rock except for rare 1- to 2-cm-thick light colored bands of quartz
scattered flakes of black biotite (<1 mm) and compositional layers defined by alternating quartz-rich and mica-rich horizons 1-25 mm thick.
and muscovite that probably represent true bedding. In thin section, fine-grained matrix consists of quartz (50-70%), muscovite (15-30%), and
Quartz-muscovite schist with porphyroblasts of biotite,garnet, and andalusite. Fine-grained quartz-muscovite schist with scattered
prominent streaky areas of graphitic material. Lenticular porphyroblasts (0.1 to 0.5 mm) are altered to yellow-brown limonite. Pervasive slaty
porphyroblasts of biotite. Also includes local horizons of interlayered amphibolite.
cleavage is locally crenulated. Small isoclinal folds locally. Basal 1.5 m-thick, black to blue-black, medium-grained, garnet quartzite is
distinctive. Garnets are anhedral, altered, and red-weathering. Contact with Piedra Lumbre Formation is gradational.
Andalusite schist-Distinctive, black, biotite schist containing large knobs of andalusite. This unit is only a few meters thick and appears to
Xvsa
pinch out laterally in both directions.
Rinconada Formation, R6 schist member-Small exposure in northwestern map area. Tan, gray, silver quartz-muscovite-biotite-staurolite-
Xhr6
garnet schistose phyllite interlayered with fine-grained garnetiferous muscovite quartzite. Euhedral staurolites (<5 cm) abundant in some
Amphibolite-Includes a wide variety of amphibolite bodies, lenses, and layers, and textures. The predominant rock type is fine- to medium-
Xva
layers. Small euhedral garnets (<2 mm) throughout. Strong parting along well-developed foliation. Sharp contact with Hp. Thickness is
grained, dark gray-green to black, weakly foliated amphibolite composed of blue-green to olive-green hornblende (0.1-0.7 mm), interstitial
approximately 90 m.
quartz and plagioclase (0.1 mm), sphene, and epidote. Faint compositional layering is formed by 1-2 mm-thick white layers. Epitode veins and
zones are common, especially near pluton margins. Fragmental amphibolites containing white felsic fragments and gray lithic fragments,
Rinconada Formation, R5 quartzite member-Small exposure in northwestern map area. Variety of white to blue medium-grained quartzites
Xhr5
Xhr4
interlayered with fine-grained schistose quartzites and quartzose schists. Gradational contact with Hr6. Thickness is approximately 75 m.
elongated and flattened in foliation of fine-grained hornblende matrix, occur locally. Subangular gray quartzite clasts, black basaltic fragments,
Rinconada Formation, R4 schist member-Small exposure in northwestern map area. Medium- to coarse-grained, silvery gray, quartz-
that range considerably in texture and mineralogy.
and epidote clasts also exist within the matrix. Smaller layers and lenses within Vadito schist are mainly fine- to medium-grained amphibolites
muscovite-biotite-staurolite-garnet schist containing one or more distinctive, 0.5-2.0 m thick, layers of glassy blue quartzite, rusty red
weathering garnetiferous white quartzite, massive, extremely hard, red weathering, olive-brown biotite-staurolite-garnet-orthoamphibole rock,
white, glassy, hornblende quartzite, gray biotite-hornblende calc-schist, mylonitic blue to pink and blue, glassy quartzite, and white to gray
calcite marble. Sharp contact with Hr5. Thickness ranges from about 50-175 m.
Rinconada Formation, R3 schist member-Small exposures in northwestern map area. White, gray, bluish-green and blue, medium-grained,
Xhr3
thinly to thickly bedded, resistant quartzite with abundant crossbeds. Distinctive marker layer near center of member is 25 m-thick white, thinly
Middle tuffaceous member of Picuris Formation (late Oligocene to early Miocene)-Light buff, yellowish, and locally white ashy/quartzose,
silty, fine sand to pebbly sandstone. Very friable to somewhat friable, moderately(?) to very poorly sorted, commonly bimodal, massive. Very
Tpm
Felsic schist, undivided-Includes a variety of quartz-muscovite-plagioclase schists. Coarser-grained felsic rocks are tan to pinkish quartz-
Xvf
Puntiagudo Granite Porphyry-Quartz monzonite to granodiorite. Phenocrysts of Carlsbad-twinned microcline (<1cm) and rounded quartz in
Xpgp
bedded, ridge-forming quartzite. Sharp contact with Hr4. Thickness is approximately 75 m.
Rinconada Formation, R1-R2 schist member- exposed? Lower unit of fine- to medium-grained, tan to silver, quartz-muscovite-biotite schist
Xhr1,2
albite-garnet schist containing interlayers of 1-10 cm, red, gray, or tan weathering, fine-grained muscovite-garnet quartzite. Abundant
Td
Qto
4000000
38
Qto
Qty
Era
Xpgp
Period
Epoch
Qg
Qg
XpgpQTg
Qto
Qg
D
Qg
C
3998000
33
B
Age
(million
years)
Volcanic and Plutonic
Sedimentary
Qal
Holocene
36°7'30"N
28 5
Qc, Qlb
0.01
442000
443000
444000
105°37'30"W
0.25
0.5
1
1.5
2
Kilometers
CONTOUR INTERVAL 20 FEET
DRAFT
NMBGMR OF-GM 62
NATIONAL GEODETIC VERTICAL DATUM OF 1929
This work was performed under the STATEMAP component of the USGS
National Cooperative Geologic Mapping Program. Funding for geological
mapping was provided by the U.S. Geological Survey and the New Mexico
Bureau of Geology and Mineral Resources, a division of New Mexico Tech.
This draft geologic map was produced from scans of hand-drafted
originals from the author(s). It is being distributed in this form because
of the demand for current geologic mapping in this important area.
The final release of this map will be made following peer review and
redrafting in color using NMBGMR cartographic standards. The final
product will be made available on the internet as a PDF file and in a
GIS format.
53
Blueberry
B
ueberry H
Hill
Fm and Lama
Fm
2 34 Ma
This and other maps are available in PDF format from:
http://geoinfo.nmt.edu/statemap
or contact:
NMBGMR Publications -- [505] 835-5410
NMBGMR Geologic Information Center -- [505] 835-5145
Ce
3 53 Ma
o de o C u
No Agua Pea
Se v e a Fm basa
2 8 4 8 Ma
La Seg a Pea
3 9 Ma
4 06 Ma
Ce o Mo no 4 32 Ma
Lo Mogo e
T e O ea
4 75 Ma
Cham a Mbr
and bas n
sed men o
Tesuque Fm
Ce o Neg o 4 84 Ma
Ce o d
Tao e
QTg
Upper San a Fe Group
4 84 Ma
4 84 Ma
Ce o de a O a 4 97 Ma
om US H
Chama E R o
Member
Tesuque Fm
Uppe
vo can c as c
mb P cu s
18 6 Ma
R o Hondo 19 6 Ma
Sun h ne Pea Tu
23 33 Ma
Ama a Tu
qua
25 Ma
a e 26 0 Ma
Tg
Cham a Mb and
bas n
sed men
o Tesuque Fm
M
16 4
Su phu Gu h 24 7 Ma
L ano Quemado b ec hyo e 28 35 Ma
T ea u e Moun a n Tu
Tpl
~29 Ma
34 35 Ma u
Mogo on Da
ed
om
o
Lower
cong omera e
mbr
P cur s Fm
Ash n Tp nea P a
49
Pre vo can c redbeds?
?
?
?
Dako a Gp G ane os Sh G eenho n Sh Ca e Fm
N ob a a Fm P e e Sh T n dad Ss Ve me o Fm
Ra on Fm Po son Canyon Fm
Cretaceous
144
Jurass c
En ada Fm Be Ranch Fm Mo
206
248
Perm an
290
Pennsy van an
IP/M
323
Unit Name
Tpmc
Tpm
M dd e
u aceous
mbr
S o P cu s M ns
Td
Tpu
Am
D xon
Member
Tesu ue Fm
Tesuque
M
Basa c as H
w
7751 ~20 Ma
Pum ce c as s Ce o B anco 23 Ma
m
M
Vo can c c as N P cu s 25 16 Ma
Wh e ash Ce o B anco 25 17 Ma
gn mb
e c as H
7751 25 5 Ma
Material Sampled
Material
Analyzed
NMBGMR
UTM N
Lab #
basalt
whole rock
4006190
437825 Scattered basalts near Vadito.
basalt clast
groundmass
concentrate
4007375
434565
conglomerate
8 sanidine
4005963
439400 Conglomerate on top of Cerro Blanco.
pumice clasts
8 sanidine
4006609
437536
Pumice clasts in conglomerate from
NE of pueblo proper.
white pumice clasts
in gray
conglomerate
9 sanidine
54785
4004797
442758
Aby site 251B. Rio Pueblo section.
"whole rock" with white pumice.
Same location as Pen-4.27.031 and Pen-4.27.03-2.
UTM E
Description
Comments
Pen-7.29.01-1
7/29/2001
5.67 +/- 0.12
Minumum age for
eruption of basalt.
Tb (Ocate basalt)
Pen-2.18.03-1
2/18/2003
19.78 +/- 0.24
Maximum age of Tpu.
Tpu (upper volcaniclastic member of Picuris Fm)
Pen-7.29.01-2
7/29/2001
23.010 +/- 0.090
Mixed population.
Maximum age.
Tpmc (cemented middle tuffaceous member of
Picuris Fm)
Pen-7.28.01-2
7/28/2001
23.707 +/- 0.042
Good, single population. Tpm (cemented middle tuffaceous member of
Maximum age.
Picuris Fm)
Pen-4.27.03-3
4/27/2003
25.07 +/- 0.10
Eruptive age of pumice. Tpm (middle tuffaceous member of Picuris Fm)
Pen-4.27.03-2
4/27/2003
25.13 +/- 0.08
Eruptive age of ash.
Tpm (middle tuffaceous member of Picuris Fm)
crumbly white ash
7 sanidine
54781
4004797
442758
Aby site 251A. Rio Pueblo section.
Single pink pumice.
Same location as Pen-4.27.031 and Pen-4.27.03-3
Pen-4.9.03-1
4/9/2003
25.17 +/- 0.07
Eruptive age of ash.
Perhaps Amalia Tuff.
Tpm (middle tuffaceous member of Picuris Fm)
bright white dense
ash
12 sanidine
54782
4005890
439325
Aby site 211d. Ash ledge visible from
below at Cerro Blanco. Bed ca. 1m
thick.
Same location as Pen-7.29.013 (not datable) collected by
Bauer.
Pen-2.18.03-2
2/18/2003
25.93 +/- 0.22
Maximum age of Tpu.
Tpu (upper volcaniclastic member of Picuris Fm)
ignimbrite clast
26 small
sanidine
4007375
434565
Purple ignimbrite clast from Tpu near
top of hill 7551'.
Amalia Tuff?
Pen-4.27.03-1
4/27/2003
27.46 +/- 0.66
Biotite age, may be too
old.
Tpmc (middle tuffaceous member of Picuris Fm)
single large gray
pumice clast
biotite (laser
step-heat)
4004772
442752
Aby site 88. Biotite pumice from Rio
Pueblo section.
Same location as Pen-4.27.032 and Pen-4.27.03-3.
Pen-7.29.01-5
7/29/2001
27.721 +/- 0.046
Good single population.
Highly accurate eruptive Tpm (middle tuffaceous member of Picuris Fm)
age.
pumice clasts
13 sanidine
4005644
439738
Pumice-rich conglomerate from S. of
Vadito Hill, Kelson collected from base
of middle member.
PEN-4.30.02-1 4/30/2002
not datable
Xenocrystic crystals of
plagioclase or quartz.
53505
4007320
434600
Off-white fine-grained layer from half
way up Hill 7551'. This is resample of
PEN-7.28.01-1.
Pen-7.28.01-1
7/28/2001
not datable
Pen-7.29.01-3
7/29/2001
not datable
Pen-2.18.03-3
2/18/2003
Pen-4.3.03-1
QLPLOMMP
Pen-4.8.03-1
4/8/2003
Pen-4.7.03-1
4/7/2003
Vesicular basalt clast from near top of
hill 7551'.
Sang e de C s o Fo ma on
A am os Fo ma on
F echado Fo ma on
Ances ra
Rocky
Moun a n
Orogeny
54786
Tpm (middle tuffaceous member of Picuris Fm)
off-white ash(?)
Tpm (middle tuffaceous member of Picuris Fm)
white ash
no datable
material
142
4007320
434600 White ash from Hill 7551'.
Tpm (middle tuffaceous member of Picuris Fm)
white ash
glass
143,
53859
4005882
439270 White ash from Cerro Blanco.
not submitted
Tpmc (cemented middle tuffaceous member of
Picuris Fm)
conglomerate
4004600
Outcrop N of NM-76, at village of Rio
442450 Pueblo. Conglomerate with pumice
clasts.
submitted
Td (Dixon Member of Tesuque Fm)
white dense ash
3999179
Aby site 153d. 7cm lense over 2m? In
437777 fluvial Td gravel in Canada de los
Alamos.
Tpm (middle tuffaceous member of Picuris Fm)
2 dark gray basalt
clasts
4006255
437698
Aby site 190. Basalt clasts from within
Tpu.
Tpm (middle tuffaceous member of Picuris Fm)
grayish-white semidense ash
4007400
434460
Aby site 176. Bioturbated ash from
gully just west of hill 7751'.
Tpm (middle tuffaceous member of Picuris Fm)
pumice rock
4005656
439843
Pumice-bearing volcaniclastic sed from
SW side of Vadito Hill in Picuris Fm.
These two samples have
similar chemistries, but
are from different
eruptions.
son Fm
Moenkop Fm San a Rosa Fm Ga a C eek Fm
T u o Fm Johnson Gap Fm
Tr ass c
Interp of Age
34 5 Ma
Ash n Tp nea Ta pa 34 64 Ma
A oyo Penasco G oup
M ss ss pp an
354
Devon an
Pen-12.11.03-1 12/11/2003
417
Same location as Pen-7.28.011 (not datable) collected by
Bauer.
S ur an
443
The Great Unconform ty
Ord v c an
pÉÇá ã Éå í ~ê ó =` ä ~ë í =` ç ì å í ë =Ñç ê =` Éå ç ò ç á Å=r å á í ë =á å =í ÜÉ=mÉå ~ë Åç =nì ~Çê ~å Öä É
Sample Site #
543
O o Ca en e Sands one Mbr
Tesuque Fm
Ea es Jemez vo can c e d e up on
Red R e 24 6 Ma
M
7 Ma
Cambr an
N
24 3 Ma
R
Pum ce c as R o Pueb o 27 5 +
28 4 Ma
65
5 44 Ma
11 2
Mo
27 7 Ma
Ar/Ar age
490
Ce o Mon o o 5 88 Ma
23 8
A
M
54 8
Tb O a e ba a nea Vad o 5 67 Ma
Bea Can on 23 9 Ma
Pum ce c as s Vad o H
27 84 Ma
Pa eocene
Guada upe M n 5 34 Ma
Lu e o Pea
Tu
37
Ce o Ch o 5 32 Ma
O a e ba a
New Mexico Bureau of Geology
New Mexico Tech
801 Leroy Place
Socorro, NM 87801-4796
[505] 835-5420
http://geoinfo.nmt.edu
36
Taos P a eau Vo can c F e d
2
Miles
0
Pliocene
P
ocene
1.5
M ocene
1
Tertiary
Tert ary
0.5
N of Picuris Mtns
M
U e M n 2 7 Ma
La r Vo can c F e d
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.
P nebe o o Pea
San An on o M n 3 05 Ma
e
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.
0.25
?
M T
1:24,000
0
Qqg
Bandelier
Bande
e Tuff
Tu
M
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.
Jemez Vo
Volcanic
can c F
Field
ed
Qg
Ash near S
A
Stakeout
(1.27 M
Ma)
1.8
1
8
October 2005
Magnetic Declination
December, 2005
09º 35' East
At Map Center
Tshirege
T
h ege Mbr
Mb of
o Bandelier
Bande e Tuff
Tu (1.22
1 22 Ma)
Ma
Otowi
O
ow Mbr
Mb of
o Bandelier
Bande e Tuff
Tu (1.61
1 61 Ma)
Ma
Cenozoic
q̧
by
Paul W.Bauer, Keith I. Kelson, and Scott B.Aby
Qfo, Qto
0.78
te
COMMENTS TO MAP USERS
441000
La
Jicarita Peak
440000
105°40'0"W
rly
Ea
El Valle
Tres Ritos
439000
e
Penasco
Ranchos De Taos
438000
Geologic Map of the Penasco 7.5 - minute Quadrangle
Base from U.S Forest Service 1961, from photographs taken 1961
Revised from photographs taken 1988 and field checked in 1995.
1927 North American datum, UTM projection -- zone 13N
1000- meter Universal Transverse Mercator grid, zone 13, shown in red
Taos SW
437000
dl
105°42'30"W
P e s ocene
Pleistocene
436000
Ma on Pa
M
M
435000
id
434000
0.13
M
433000
Quaternary
te
La
Qfy, Qty
33 7
F h Can on Tu
N
T ans on om
c us a sho en ng o
ex ens on
(Includes significant regional rocks and deposits)
Td
mbr
P cur s Fm
27 38 Ma
La e
Description of
Site
Ydd
dd
900
Grenv e
Orogeny
Ypqm
M dd e
1600
Maza za
Orogeny
Xpgp Xgp Xgm
Ear y
Xvrp
Xvu Xvf Xvq Xcam
Xvm x Xva
Me ap u on c & me avo can c ocks 1 75 Ga
2500
Map Unit
3
4
4
Ojito
Road
El Valle
Road
El Valle
Road
Qg
T upper
T lower
6
7
11
Xhu Xhp Xhp Xhr6 Xhr5
Xhr4 Xhr3 Xhr3q Xhr1 2
Xho Xhow Xhor Xhosq
Xhos Xhog Xho3 Xho2
Xho1
Xvht
Xvm Xvm3 Xvm2 Xvm1 Xvs
Xvsa
UTM E (NAD27)
12
15
22
23
27
30
Chamisa
N side
l road
mesa
cut
Qg
Ttd
UTM N (NAD27) 3999643 3999095 3999095 4004119 4000429
Hondo
Group
QTg
Vad to
Grou
Group
Td
Tectonic
Events
Ca pen e R dge Tu
Laram de Orogeny
Penasco Area Rocks and Deposits
4
San Juan Vo c F e d
27
3
O gocene
gocen
Qg
Time-Stratigraphic Chart for the Penasco Quad Area
Eocene
Qfy
9
Qg
Qg
3999000
26
Mesozoic
13
Date
Collected
Sample #
15
Qal
Qg
5
Paleozoic
Td
Geochronology Samples from the Penasco Quadrangle
&/M
Proterozoic Eon
Td
QTg
Qg
28
Slow
S
ow rrift ex
extension,
ens on basin
bas n subs
subsidence
dence and footwall
oo wa up
uplift. Integrated
n egra ed ax
axial
a dra
drainages.
nages
4
Td
Qal
Truchas
Ortega Formation black quartzite-Southwest of the Pilar-Vadito fault. Dark gray to black, massive, medium-grained quartzite. Commonly
Xho2
Td
Qg
Trampas
medium-grained quartzite, qray quartzite, garnet-bearing dark quartzite, and tan cross-bedded quartzite. Thickness is approximately 250 m.
Xvrp
weakly foliated, except locally along contacts where foliation is well developed. Generally concordant with country rock contacts and foliation.
ex ens on
3999000
Carson
Ortega Formation mixed quartzites-Southwest of the Pilar-Vadito fault. Various quartzites including reddish coarse-grained quartzite, brown
Xho3
30
Qg
Qg 12
105°45'0"W
evidence for grain size reduction and dynamic recrystallization. Shearing is related to adjacent ductile Plomo fault.
the Plomo fault.
trace of scattered exposures may indicate the original course of the basalt flow along a Pliocene paleovalley.
Qal
Td?
20
36°7'30"N
vitreous quartzite with well-developed south-plunging kyanite extension lineation. Much of this unit is a quartz mylonite, with abundant
andalusite porphyroblasts up to 8 cm across. Upper unit of gray to tan, red weathering, coarse-grained quartz-muscovite-biotite-staurolite-
Qfo
Td?
3998000
Ortega Formation gray quartzite-Northeast of Pilar-Vadito fault, near Picuris Canyon, north-central map area. Medium-gray, fine-grained,
with small euhedral garnets (<2 mm) and scattered euhedral staurolite twins (<1.5 cm). Near base are black biotite books (<2 cm) and local
Qfy
Qto
Qal
between Vadito Group feldspathic schist and Hondo Group Ortega Formation.
mm sphene crystals common. Accessory minerals are muscovite, allanite, epidote, magnetite-hematite, apatite, and zircon. Locally contains
14
QTg
Qfy
Qal
Qfy
Td
Td
Qto
4001000
5
10
Qfy
5
4000000
5
QTg
muscovite schist with porphs and quartz eyes. Typically contains kyanite and andalusite. This unit has mineralogy and textures transitional
northwestern map area. Base is unexposed.
tabular megacrysts of Carlsbad-twinned microcline up to 9 cm in length. Myrmekite and albite rims on plagioclase are common. Massive to
Cemented part of middle tuffaceous member of Picuris Formation (early Miocene)-This unit is characterized by silica cementation and is
here informally defined as the interval between the lowest and highest pervasively silica-cemented beds within the Picuris Formation. Some
beds in this interval, in some locations, are either poorly cemented or cemented with both calcium carbonate and silica. Buff to white and/or
pinkish silty sandstone to fine cobble conglomerate. Nonfriable to strong, very fine lower to very coarse upper, very poorly to moderately
sorted, rounded to subangular, thinly to thickly bedded, silica-cemented. Locally contains a basal portion of poorly sorted pebbly/gravelly
sandstone and/or cobble/boulder conglomerate composed exclusively of Precambrian clasts. This portion of the unit grades upward (or
laterally?) into pebbly/gravelly sandstone and conglomerate composed of an increasing proportion of Tertiary pumice and/or Tertiary volcanic
clasts relative to Precambrian clasts. In exposures along NM-76 between Chamisal and Penasco (The ‘Chamisal exposures’ of Aby et al.,
2004) the lowest, exposed, cemented part of the middle member is at least 13 m of moderately to moderately well sorted, thickly bedded, subrounded to angular cobble and boulder conglomerate composed of Precambrian granite(46%), quartzite(26%), amphibolite (26%), phyllite
(1%), and schist (1%). Although the lowermost 1-3 m of this conglomerate are not silica-cemented, and thus should be part of Tpm, these
exposures are not map scale and are therefore shown as Tpmc on the map. In areas to the east and north of the Penasco quad, Rehder
(1986) mapped a Precambrian-derived basal conglomerate beneath beds equivalent to our middle member. It is possible that the lowest part
of the cemented section in the Chamisal exposures is correlative to these beds. Soft-sediment deformation features exist in uncemented parts
of the middle member, particularly at its upper contact, but are spectacularly preserved by silica cementation in the Chamisal exposures. The
upper contact of the Tpmc (and Tpm) is the top of the last silica-cemented bed. This contact locally displays flame structures. Rare
paleocurrent indicators show transport from the northwest, north, and northeast. Approximately 10-35 m thick. Tpmc is everywhere found at
the top of the Tpm and sometimes includes all or part of the gradational and/or interfingering contact with Tpu. Assignment of Tpmc to the
middle member is a matter of convenience, as some beds are dominated by Tertiary volcanic clasts and are therefore sedimentologically more
similar to Tpu. However, Tpmc is a mappable and useful field unit. In discussing the Picuris Formation as a whole, Aby et al. (2004), did not
differentiate this silica-cemented portion as a separate unit and therefore parts of Tpmc as mapped here would be either Tpm or Tpu by
definitions used in that report. Current age constraints, based on 40Ar/39Ar geochronology indicate that Tpmc is younger than approximately 23
Ma.
36°10'0"N
Tpu
Ar/ Ar date
Upper volcaniclastic member of Picuris Formation and/or Chama-El Rito member of Tesuque Formation (early to middle Miocene)Red to purple pebble and gravel conglomerate. Very friable to nonfriable, very poorly to moderately well sorted, poorly rounded to rounded,
thickly to thinly bedded, typically carbonate cemented. Composed predominantly of Tertiary volcanic clasts, rounded Precambrian quartzite
clasts, tan, pinkish, and whitish, loose to slightly friable, very fine lower to very coarse upper, moderately well to very poorly sorted, subangular
to subrounded and rarely rounded, thinly to thickly bedded, locally carbonate-cemented, arkosic to lithic sandstone beds, and brick-red to pink,
tan to brown, orange, and whitish, loose to slightly friable, moderately well to poorly sorted, thinly to thickly bedded, locally weakly carbonate
cemented, sandy silt to silty clay beds. Most contacts between beds are abrupt and the basal contacts of the coarser beds are commonly
scoured. Exposures become more and more rare upward in the section due to an increase in the proportion of fine beds(?). Upper contact is
not exposed in the map area, but appears to be depositional and possibly gradational and/or interfingering (or the base of the overlying Dixon
member of the Tesuque Formation may contain reworked Tpu). The upper contact is placed at the top of the highest conglomerate bed that is
dominated by Tertiary volcanic clasts rather than by Paleozoic sedimentary clasts. Weathering of volcanic clasts within this unit is highly
variable. In many exposures, volcanic clasts are well preserved and coherent, whereas in others, various stages of decomposition exist. In
some exposures, pumice lapilli within welded tuff clasts are completely weathered, whereas the welded matrix is relatively pristine. Where Tpu
is exposed beneath terrace deposits, such as south of Picuris Pueblo and at the northwest tip of the Llano surface, 90% of volcanic clasts are
highly weathered. Approximately 10-100 m thick. Stratigraphic relations between these strata and others mapped as Chama El Rito Member
of Tesuque Formation by Steinpress (1980) and Koning and Aby (2003) are discussed in Aby et al. (2004). A basalt clast from the basal part
of the upper member at Hill 7751’ was dated at 19.78 +/- 0.24 Ma (Aby et al., 2004) and the unit is overlain by the Dixon member of the
Tesuque Formation which is estimated to be 12.5 to 14.5 Ma regionally (Koning and Aby, 2003). Current age constraints, based on 40Ar/39Ar
geochronology and regional depositional patterns, indicate that Tpu spans a range from less than 19.8 Ma (or ~18 Ma) to approximately 15
Ma (based on inferred age of overlying Dixon member of Tesuque Fm.
F'
6
11
Qfo
QTg
Qfy
12
3
Ortega Formation quartz-mica schist-Northeast of Pilar-Vadito fault, near Picuris Canyon, north-central map area. White to pink, quartz-
Xhos
Xhog
of 5.67 +/- 0.12 Ma confirms that Tb is time equivalent to rocks of the Ocate volcanic field to the east. Locally up to 10 m thick. East-to-west
Dixon member of Tesuque Formation of Santa Fe Group (middle Miocene)-Red, tan, beige, and locally greenish and/or yellowish sandy
to clayey silt and silty clay. Loose to slightly friable, moderately well sorted to moderately poorly sorted, mostly massive(?) but locally thinly to
moderately thickly laminated and/or in beds approximately 0.1-6(?) m thick. Locally moderately carbonate cemented. Interbedded with tan,
brownish, reddish, and characteristically light olive green conglomerate to fine arkosic sandstone that is very friable to nonfriable, very fine
lower to very coarse upper, moderately to very poorly sorted, generally subangular to subrounded, thinly to thickly bedded, and locally
carbonate cemented. Conglomerates contain abundant poorly to moderately rounded clasts of Precambrian quartzite and Paleozoic
sandstone, limestone, and siltstone. Locally, conglomerates also contain clasts of Tertiary volcanic rocks, especially in the coarser fraction, but
quartzite and Paleozoic sedimentary clasts everywhere predominate (by definition). Sedimentary features other than plane lamination are not
common but include ripple marks, cross beds, and lateral accretion (point-bar) foresets. Contacts between beds are typically abrupt and bases
of sandstones and conglomerates are commonly scoured, with 0.01-1 m of relief. Imbrication of clasts is not common and often chaotic, but is
locally well developed (e.g., in Canada de los Alamos exposures). Sandstones and conglomerates are preferentially cemented with calcium
carbonate. Carbonate cement commonly forms a sparry white matrix between grains and helps to explain the overall rarity of sedimentary
features. Exposures range from excellent in the coarse-grained beds exposed along the southern scarps of the Llano de la Llegua and on the
northwest side of Canada de Los Alamos, to almost non-existent in dominantly fine-grained beds south and west of Chamisal Creek. Even
where the unit is coarse-grained, good, natural exposures are limited to south- or southwest-facing slopes. Paleocurrent indicators
(imbrications and the strikes of channel walls) indicate transport from the south, southeast, and southwest. Exposed thickness is 75-100 m.
6
7
Qto
Tb
10
88
Qto
bedded quartzite. May be equivalent to part of Hos.
Peñasco Quartz Monzonite-Biotite quartz monzonite to granodiorite. Composed of quartz, plagioclase, microcline, and biotite. Euhedral 1
Ypqm
39
boulders of coarse-grained, reddish, Pennsylvanian sandstone derived from the Sangre de Cristo Mountains to the west. Field relations
Td
Qfy
Qto
Ortega Formation schistose quartzite-Northeast of Pilar-Vadito fault, west of Picuris Canyon. Thin horizon of white, muscovite-rich, well-
Xhosq
below the Ocate basalt flow. The deposit appears to be composed entirely of well-rounded, fairly well-sorted, sub-rounded cobbles and
5
10
Qfy
Qto
40
indicate that Tb basalt flowed down a paleovalley that was mantled by these gravels. Thickness is estimated at a few meters.
9
5
4002000
Qg
Qty
Qty
36°10'0"N
QTg
8
Qfy
12
QtoQfy
Tpmc
Tpu
Qlb
the Ho2-Ho3 section southwest of the Pilar-Vadito fault. Generally sharp contact with How.
represented, and at least one generation is younger than the youngest granite at 1450 Ma (Long, 1976).
High alluvial gravel (Pliocene?)-Poorly exposed, coarse-grained, gravel to boulder deposit that is mapped only near the top of Vadito Hill,
Tg
QTg Qal
Qty
Qto
Qto
basalt is equivalent to a 5.7 Ma (O'Neill and Mehnert, 1980) basalt flow of the Ocate volcanic field to the east. A new whole-rock
Rap d r
4003000
Qal
Qty
Qto
Ocate basalt (Pliocene)-Dark-gray, vesicular, olivine tholeiite basalt flow found on high mesa in east-central map area, and as scattered,
A'
12 35
6
12
Qto Qto
Qto
Qto
13
14
35
Tpu
6
Qfy
13
Qfy Qto
4 19
Qty
Qto
4
6
Qto6
Qto
Qfy Qfy
Qty
Qto
Qto
Tpu
12
8
Qto
Qty
Qal
3
10
Qg
Qty
Qto
Tpmc
12
6
Qfy
Xvcam
Qfy
Qfy
Ortega Formation reddish quartzite-Northeast of the Pilar-Vadito fault. Reddish, coarse-grained quartzite Probably equivalent to some of
Xhor
Pegmatite-Predominantly simple pegmatites of quartz, K-feldspar, plagioclase, and muscovite. Pegmatite bodies typically are dikes or lenses,
xxx
However, Rehder (1986) cites a 1986 personal communication from R.L. Nielsen (Stephen F. Austin State University) that states that this
4006000
9
12
Tpu
underlying reddish quartzite (Hor).
isolated remnants to the west. This unit was considered equivalent to 2.8-4.5 Ma flows of the Taos plateau volcanic field by Miller et al. (1963).
Tpm
22
Tpmc
QTgTb
QTg
Qlb
Qg
Qfy
Qto
Tpm
Qto
QTg
Tpu
22
15
Qfo
Qty
Tpm
5
Tb
Tg?
Qfo
Tpu
5
Xvu
Tpm
6
Tb
(27.72 +/- .06 Ma)12
Tpm
Qfy
Qty
Qg
Tpmc
commonly is associated with dark layers. Northeast of the Pilar-Vadito fault, most of the Ortega Formation consists of this unit plus the
locally aligned parallel to country rock foliation. Thicknesses range from 2 cm to 15 m. More than one generation of pegmatite formation is
Tpm
Qfy
Qfo
of rutile, hematite, and ilmenite that define crossbedding. Fine muscovite commonly is present on quartz grain boundaries, and kyanite
No compositional border zone. Mafic microgranitoid enclaves are common, especially near borders. U-Pb zircon isotopic age of about 1450
Qty Qfy
Qfo
Pumice congl. PEN-7.29.01-2 (22.25 +/-1 to 23.64 +/- .01 Ma)30
Tb
Maximum thickness of 10 m.
Qty
16
Tpmc
10
4007
QTg
Qfo
Ortega Formation massive white quartzite-Northeast of the Pilar-Vadito fault. Massive, white to light gray, vitreous quartzite with dark layers
Xhow
boulders of Proterozoic quartzite. Found on high erosional pediment surfaces, and commonly forms colluvial veneer on underlying units.
36°12'30"N
000
10
zircon. Gradational contact with Rinconada Formation. Thickness is approximately 800-1200 m.
Diorite dike (age unknown, but probably Middle Proterozoic)-Dark green-gray quartz diorite dike intruded into Proterozoic rocks. Dike is
vertical, with strikes clustered around an azimuth of 150 o. Composed of pale green clinopyroxene (Cr-diopside?), zoned plagioclase
(labradorite?), and minor quartz, magnetite, and ilmenite. Commonly altered to chlorite and clay. Pyroxene and feldspar show normal plutonic
textures. Locally, dike is laced with carbonate veins. Generally less than 1 m wide. Contacts between diorite and country rock are sharp and
commonly correspond with local fracture zones. Similar dikes have been mapped in the Carson Quadrangle of the northwest Picuris
Mountains.
dd
Older alluvium (Pliocene to early Pleistocene)-Poorly sorted sand and gravel deposits, typically with layers containing large rounded
QTg
concentrated in thin muscovite schist horizons. Common accessory minerals are ilmenite, hematite, tourmaline, epidote, muscovite, and
PROTEROZOIC IGNEOUS ROCKS
TERTIARY ROCKS AND DEPOSITS
70
QTg
well-crossbedded, and kyanite-bearing. Crossbeds defined by concentrations of black iron-oxide minerals. Aluminum silicate minerals are
thin interlayers of light quartz-rich and darker mica-rich schist. Exposed only in a small area in the core of the Copper Hill anticline in the
Qqg/Tpl(?) Quartzite-rich alluvial (and colluvial?) deposits that overlie Tpl (late(?) Quaternary?)-Surface is covered with Precambrian quartzite
clasts from 2 mm to about 3 m, rare Pilar slate clasts to about 7 cm, and extremely rare schist clasts to about 5 cm. Apparently formed as a
lag deposit over Tpl. No exposures were found in this area that unequivocally identify Tpl, but rare accumulations of fine material in the ‘lag’
are more consistent with the greenish and pale grayish color of fines in Tpl, rather than the orange and brownish color of Quaternary fines
exposed elsewhere on the quadrangle. These deposits exist at 8000-9000 ft elevation and are shaded in winter.
54
70
Qto Tpu
Tpu
15
Tb
or
P
Qto
11
Qto
QTg
11 45
Qty
Qfy
4008000
60
24
Qfo
22
Qfy
12
Xvu
4005000
Qfy
70
Tb
12
Tpmc
Qto
Qto
Tpm?
Qfy
59
QTg
Qfo Qfy
11
Undifferentiated Quaternary gravel deposits (middle to early Pliestocene)-Typically buff to brownish, rounded to well rounded, crudely
bedded, uncemented, quartzite-rich conglomerate and sandy conglomerate. Deposits are typically clast-supported; clasts are pebbles,
cobbles, and boulders. Map unit typically exists as isolated remnants on ridge crests or hill tops; soil characteristics are unknown. Thickness is
estimated to be as much as 5 m.
Qg
60
Qfo
Ypqm
Tb
Tpu
Qto
Tpm I
Qfo
80
15
22
Qfy
60
Ortega Formation, undivided-Gray to grayish-white, medium- to coarse-grained quartzite. Generally massive and highly resistant. Locally
Xho
Undivided Mississippian and Pennsylvanian sedimentary rocks of the Tererro Formation of Arroyo Penasco Group (Mississippian,
Meramecian and Chesterian), Espiritu Santo Formation of Arroyo Penasco Group (Mississippian, Osagean), Alamitos Formation
(late Desmoinesian), and Flechado Formation (Morrowan-Atokan-Desmoinesian)-Consists chiefly of Pennsylvanian, poorly exposed,
olive, brown, red, and dark gray shale and siltstone plus fine- to coarse-grained sandstone with lesser amounts of conglomerate and
limestone. Alamitos Formation is equivalent to the “upper arkosic limestone member” of the Madera Formation to the south. Flechado
Formation is equivalent to La Posada Formation to the south, which is equivalent to the Sandia Formation and the “lower gray limestone
member” of the Madera Formation. Fusilinids collected from the exposures southeast of Taos Pueblo are Desmoinesian in age (B. Allen,
personal communication, 2000). To the north, in the Ranchos de Taos Quadrangle, the Tererro Formation consists of 1-2 m of basal
stromatolitic limy sandstone overlain by about 7m of dolomitic limestone, overlain by about 12m of calcitic dolomite with stromalites and
bedded and nodular chert (Armstrong and Mamet, 1990). Thickness is approximately 20 m. The Espiritu Santo Formation consists of the basal
Del Padre Sandstone member of basal conglomerate, quartz sandstone, siltstone, shale, and minor limestone beds at top. It grades into the
overlying Tererro Formation. Thickness of the Pennsylvanian section is unknown, but a minimum of approximately 2000 m.
⁄P/M
Qfo, Qto Alluvial fan and terrace deposits (middle Pleistocene)-Poorly sorted deposits of silt, sand, and pebbles. Deposits are typically matrixsupported and poorly bedded. Clasts are primarily Paleozoic sedimentary rocks and Precambrian granitic and metamorphic rock types.
Moderate pedogenic development, including A, Bt, Btk and Bk soil horizons and stage III and IV calcium carbonate development. Where
preserved, upper soil horizons are commonly affected by surface erosion. Map unit Qto typically occurs as isolated remnants on ridge crests,
whereas Qfo exists as mountain-front fans. Thickness up to 3 m.
Xho
43
QTg?
Basalt PEN-7.29.01-1 (5.65 +/- >15 Ma)
Qty
exists as young mountain-front fans and valley fills in small tributaries. Thickness up to 3 m.
60
87
Xgp
Tpm
Qfy
&/M
gradational contact with Hr3. Lower and upper unit have previously been subdivided into R1 and R2, respectively, based on mineralogy
(Nielsen, 1972). Thickness is approximately 265 m.
PALEOZOIC ROCKS
horizons and stage I to II calcium carbonate development. Map unit Qty is typically on valley floors of large to medium drainages, whereas Qfy
72
Xgp
Qg
Tpmc
Qfy
Xgp
Qfo
Qfy
commonly silty sand probably deposited from overbank flow. Weak to moderate pedogenic development, including A, Bw, Bwk and Bk soil
4009000
Xva
Qfy
Pumice congl. PEN-7.28.01-2 (23.74 +/- .06 Ma)18
Proterozoic quartzite, slate, schist, metavolcanic, and granitic rock types, and Tertiary granitic and volcanic rocks. Uppermost sediments are
Qfo
Qfo
Qg
unconformably overlie Tertiary volcanic or sedimentary rocks, rarely Proterozoic rocks. Clasts are primarily Pennsylvanian sedimentary rocks,
65
Xvrp
84
QTg?
Xgp
Xgp
53
staurolites are twinned, euhedral, up to 3 cm; abundant garnets are euhedral and small (<2 mm). Strong parting along foliation plane. Sharp to
Lower conglomerate member of Picuris Formation (late(?) Eocene to late Oligocene)-Not exposed on Penasco Quadrangle, but
probably underlies areas within the Agua Caliente Canyon drainage in the northwest map area and in Picuris Canyon. Where exposed on
adjacent quadrangles Tpl consists of greenish and pale yellowish, loose to strong, poorly sorted, moderately to well rounded, sandy/silty
conglomerate that is dominated by Precambrian Hondo Group quartzite clasts from 2 mm to >2 m. See Aby et al. (2004) for a regional
discussion of this member. Current age constraints, based on 40Ar/39Ar geochronology, indicate that Tpl ranges from more than about 34.5 Ma
to less than about 28.3 Ma.
boulders. Deposits are typically clast-supported and poorly bedded; pebble and cobble clasts are typically imbricated. Terrace deposits
45
64
Tpl
Young alluvial-fan and stream terrace deposits (late Pleistocene to Holocene)-Poorly sorted deposits of silt, sand, pebbles, cobbles and
QfyQty
45
70
87
77
QTg?
Xvmix
Xvmix
Qfo
Qto
76 Qto
Xgp 76
Xvs
12
Xvs
70
XvmXvm
Xvm
Xvm Xvm
Xvm
Xvm
Xgp
Xvm
XgpXvsa
Xvm
Xvf Xvf
Xgp
Xvf
Xgp
70
68
Ash PEN-7.28.01-1
Xva?
flows (Tb) and subangular to angular boulders of basalt. Found on slopes below the basalt flows of Vadito mesa.
82
69
50
Xgp
84
Xvmix
E
Xva
Xgp
Xgp
85
Qfo
Tpm?
Xvf
Landslide deposits of basalt (late Pleistocene to Holocene?)-Small landslide blocks that are composed of intact blocks of Tertiary basalt
ex ens on
4007000
Tpu
Tpmc
Qg
Xva45
Xva
Qc/Xu
8
Qg
Xgp
Xvq
80
Qfy
Xgp
Xgp
Qqg
Xva
YddXva
Xvs Xvs
Xvq
Xva
Xgp Xvq
Xva85
4008000
Qg
Xva
78
Xvm3
Qc
A
Xvm1
Xgp
based on geomorphic features such as hummocky topography, arcuate headscarps, and discontinuity in bedrock orientations.
4010000
Qlb
Xvm
74
51
65
Xvm
53
Xgp
Xvm2
Xva
Xva
87
Landslide deposit (late Pleistocene to Holocene)-Poorly sorted sand to boulders, may include large, coherent blocks of bedrock. Identified
Qls
breccia
40
88
60
Xvq
70
79
Xvm3
Xvf
Xvs
65
Xvf
Xva
67
Xvu
Xvf
Xho2
Xvf
Xvm
Xvs
Xho1
Xho2
4009000
71
60
Xva
Xvm
overlie the Precambrian crystalline bedrock of the Vadito Group. Thickness is typically 2-5 m.
S ow r
Copp
4004000
Xva
Xvm
Qqg/Tpl?
Boulders are up to 2 m in diameter. Clasts are mostly metavolcanic and plutonic rocks, but include pebbles and cobbles of metasedimentary
80
Xvf
ult
45
Xho2
l An
er Hil
Xvf
Tpl?
The clasts are poorly sorted and are typically angular to subangular, except for the rounded quartzite cobbles and boulders derived from Qqg.
rocks. The matrix is brownish silt to fine-grained sand with some medium- to coarse-grained sand. The colluvium and talus unconformably
Xvf
60
Xho3
Colluvium and talus over Proterozoic bedrock (late Pleistocene to Holocene)-Colluvium and talus on the southern slopes of the Picuris
Qc/Xu
Mountains derived locally from Precambrian bedrock and Quaternary gravel deposits. The colluvium includes pebbles, cobbles, and boulders.
Xvht
62
Estimated thickness is 1-3 m.
4011000
ris-
65
Xho3
very coarse-grained, poorly to moderately sorted, and subrounded to subangular. There is no soil development and the sediment is loose.
Picu
59
very thin to thin and planar or cross stratified. Gravel is mostly poorly sorted, subangular to subrounded pebbles. Sand is typically coarse- to
Xgm
69
Xho3
brownish sand, gravelly sand, and sandy gravel with minor mud and silt that underlie modern ephemeral or active channels. Beds are typically
Xhos
Xvm
4010000
thickly to thinly bedded, and with locally well-developed fining upward sequences a few to tens of cms thick, particularly at Cerro Blanco. Most
sandstone beds contain a small percentage of medium lower to coarse upper grains of Pilar slate and quartzite. Thin to thick (5 cm-1.5 m)
interbeds and channel-fills of buff and black, friable, moderately to poorly sorted, subangular to subrounded, Precambrian Pilar slate and
quartzite-rich, and/or Tertiary pumice-rich conglomerate. Lower portion, just west of Cerro Blanco and just east of granitic highland in Section
29, is poorly sorted, fine- to coarse-grained, grussy, pebbly sand. Near abandoned power substation in Section 32, southwest of Vadito, it
contains rare pebbly/gravely channels that are rich in granite, epidote, slate, amphibolite, and schist(?), and a single exposure of boulder
conglomerate composed of Precambrian Penasco quartz monzonite porphyry, quartzite, and amphibolite. White ash beds (15-65 cm) are in
exposures north of the Rio Pueblo drainage. Some ash layers distinctly bioturbated. Conglomerate beds seem to increase in abundance
towards the upper contact. Some conglomerate beds contain abundant, rounded Tertiary pumice lapilli. Lapilli in lower portions of unit are
white or pink, mafic-poor, with phenocrysts of quarts and plagioclase. Near, and at, the upper contact (and also within parts of Tpmc) is a
biotite-rich pumice. Lower contact is not exposed in map area. Upper contact is mapped as the base of the first silica-cemented bed in the
section. Sedimentary features and bedding are absent to very poorly expressed, except where coarse-grained or ashy beds exist. Coarsegrained beds have scoured basal contacts with 0.1-1 m of relief. At least 150 m thick (base not exposed) in northern exposures. Primary ash
fall from the Amalia Tuff eruption has been identified within the middle member at Cerro Blanco and similar ash beds exist at Hill 7751’ on
Picuris Pueblo lands. Pumice from the Amalia Tuff eruption(s) have been identified at several places along the southeastern edge of the
Picuris Mountains (Peters, 2005). Two additional populations of pumice of approximately 23 and 27 Ma have been identified within the Tpm
(Aby et al., 2004; Peters, 2005). These pumice clasts are presumed to be derived from pre-and post-caldera eruptions in the Latir volcanic
field. Aby et al. (2004) overemphasized the carbonate-poor nature of the Tpm due to a bias toward examination of primary ash beds. Although
the bulk of this unit is somewhat less effervescent than other Tertiary units in the area, it is mostly moderately reactive in hydrochloric acid.
Aby et al. (2004) also failed to recognize small-scale fining upward sequences indicative of fluvial deposition in the upper half(?) of this unit.
These fining-up sequences are best seen on the slopes of Cerro Blanco. Current age constraints, based on 40Ar/39Ar geochronology, indicate
that Tpm was deposited approximately between 28.3 Ma and less than about 23 Ma.
Stream channel and valley-floor alluvium, and active floodplains (Holocene)-Poorly to well-sorted sand, pebbles, and boulders. Light-
Qal
69
54 K
59
Xva 50
Xvm
30
Xho
50
SURFICIAL DEPOSITS
36°15'0"N
43
Qal
Xvf
70
Xhog
DESCRIPTION OF MAP UNITS
52
50
44
Xvht
Xvm
Qqg
Plomo Fault
74
55
42
42
Xhor
Xva
59
46
53
53
Xhosq 36
Xhor
Xvf
B'
Xhr6Xhp
Xhr5
Xhr3Xhr4
Xhr12
s Fa
Xhp
Pec
o
36°15'0"N
C'
Qal
34
39
40
N side
Chamisa
l near
road
lost
Dixon
Chamisa
l ditch
47
63
82
95
107
128
137
146
188
216
3998119 4000476 4001905 4003333 4004810 4005452 4003667
249
108 f
119 a
119 b
119 c
433190
433190
435119
435310
435643
434607
432667
434214
434792
433619
434333
436214
435976
434857
436190
441857
433881
439214
438833
439762
437571
436119
440452
434143
439429
434578
434580
434585
55
57
40
75
1
44
43
92
24
17
42
25
40
66
25
25
18
24
44
54
11
21
14
6
68
26
10
66
1
25
Sandstone (Pz)
6
10
10
19
15
16
16
43
4
28
1
1
17
45
8
57
4
1
4
89
15
1
7
22
Limestone
19
32
28
18
7
19
42
10
38
28
2
21
17
Siltstone
13?
2
2
4
6
Vein Quartz
23
1
3
3
81
3
22
24
4
12
82
1
1
Basalt
1
Biotite pumice
433905
438619
438619
50
17
42
10
34
7
6
19
25
20
1 horn
coral
49
25 1
chert
47
3
5
8
3
1
1
32
89
9
1 chert
33
45
2
1
8
37
42
70
53
65
94
18
14
1
1
11
69
99
10
5
18
1
3
1
438643
438690
22
1pink
pumice
93
2
67
1
1
7
92
3
15
20
25
2
2
1
3
High
scool
upper
435643
2
1
Pilar Slate
Schist
16 a
37
9
3
21
1
153 h
437286
1
Mafic Granitoid
Unknown
152 b
25
2
46
5
137 b
438833
1
438619
5
2
Amphibolite
436792
1
7
Granite
136 c
Qg
89
4
136 b
4000714 4004738 4001667 4003810 4004738 4004143 4004040 4003667 4004333 4006238 4005214 4005619 4001119 4004095 4003040 4007357 4007352 4007345 4004929 4004714 4004595 4003669 4002667 3998119 4001167 4003452 4003452
435310
1
136 a
High
School
lower
Quartzite
Volcanic (T)
Yavapa
Orogeny
248
Telepho
chamisal
ne
middle
conglom
erate
Ttd
238
4
8
1 gar
scale?
2
69
50
2
2
8
7