Cornell Universi ity Libra
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ENGIN. FEB 7 1985

CORNELL UNIVERSITY
LIBRARIES
ITHACA, N. Y. 14853

 
BULLETIN

OF THE

State University of New Mexico

WHOLE NUMBER 108

 

 

GEOLOGICAL SERIES 3 SEPTEMBER, 1922 No. 4

 

 

GEOLOGY OF THE SANDIA
MOUNTAINS
BULLETIN

OF THE

State University of Nem Mexico

WHOLE NUMBER 108

 

 

GEOLOGICAL SERIES 3 SEPTEMBER, 1922 No, 4

 

 

GEOLOGY OF THE SANDIA
MOUNTAINS

BY

ROBERT W. ELLIS
PROFESSOR OF GEOLOGY IN THE STATE UNIVERSITY OF
NEW MEXICO AND STATE GEOLOGIST

ALBUQUERQUE, NEW MEXICO
1922
COPYRIGHT, 1922
BY THE STATE UNIVERSITY
OF
NEW MEXICO
CONTENTS

Page

Introduction SEB. SGasr ake inca asco sities G0 didnt asr ede lapis Mahe rar aeepatte eta e ae ge Ta 5
Purpose and acknowledgments ................0.-0005 me ewge” D
PROVAIOUS! WORK acvie y-syen Ropes ae oes 6 ane arid a cauavedsisenns nuwsarduacacet nines 5
RIVE! PEOSOME WOTIE as vans sispees asia vdescd Suosier aed cntiba mlacsbane W-lae Abtemaciadiadbiabearcen eta 6
GSGET ADIN 5.828 a spcavacsuataeualer asia sspa «tea nianectnseuanin oesetceres ale eames sepetlereneted 6
LOCATON: ANG; AED. cp smecn ge cages et sora cee pad sae Ba eee eee 6
Geographic and structural relations ..............0000 e000 6
Porestation, | suvveese driest ccc scecsuprtassmariaa davies sea etanhentetanl se ¥
MOTT ERE Fah or oka Coach era dusnSctbeen acteial exits a sextant tases gts psees GUE 8
ACCESSIBINIt¥ kev eae wee as ete ae ee ee ee ee ee 9
PNGQUSUBICS 2 cc ociaciye warrenna sed neo eae RD EAE PS ERS SON 10
"BODO STEM c) gigesre wes yey BasHe iste ice aasein ois lacdases aiebdareausea Geer wsdeonen den 12
SECC GLE «2h caess sie leah acai nadastn sda gn tcvep fom teerachehac ce vebaoe aa Dndvich abies Paieetents arcesavtoeeecs 12
Drainage oa ah fsa Dbl Sept eh ab tzb Sams aN Ta SUT RRR tC An are Toots 14
IDESELIPLIVE, BeolOgy a-sisccgs wernt eRe OAG Ewe ee S 15
Stratigraphy +s s.0 seen a ets SOUR UR Sani ae at Mc oy alte AON a ith ead tl 15
Sedimentary POCKS: oo. g ee Meas sere m ac este er dccucesaneoecenetin sarin: oneee 15

The Pennsylvanian ..........ccc cece net e ee eee enn 15

The Magdalena group ...........0. cece eee eeee 17

The Manzano group ‘iat Mans Eee Greens Raat SOE 20

CretaCCOUS: FOCKS) oe te seed one Gierdnck Fras eucdne ghS ela alas 21

PE MEOUS) ‘HOCIES: gasses cisricassestessctgehrase efit dasheavsiea tgp tol h staanosauaneriahis FAeemuebOuens 21
GRATE: ce orcavdatestaved odacteswee teann aie Kaede Te tis Siders Moles 21

POSE cane Oh eee es BER RES Se SUE VOU SS ENS TEER 24
Metaniophic: ®oGls) «on c2e82 osrrer eee Say eek eyes see 24
POUIGS «4iee eRe oe ERES HEPA So ee oh wR CP e Re beh PRE 24

Gneiss and quartz schist .......... 00.00: cee eee 26

SEIU GDI) gcc esa ss soci tse in easiest coop ot Soe ee A wv nh He ma Aa oath 29
Wreneral Teatures sac 244569 5968564 GRE RE OSH OE EE RES 29
Melts! 24 acs seis ee a SoS HS Ee SA ee se ee em 30
Relation of structure to topography...............2000-8 32
GEOTOBIS- TISEORY ied. 6 sacs sects yecd i tossm oe gmen be sevidcons sath wk vakacsey il ceca lin aint s 34
Mineral resources ........ iiss sa fo eat alte aahyelea vince aa reWalce oe doy it nba sab ccdabiok vagertbl ds 37
Coal x4) seals emia gee wee PALS Wane oe etd a a Re ee OS ee os 37
Bulldine’ Stones: as aac-ces S65 OES SS SS SE SS ES 38
i ion Rare MOO RA dee RADA ORE ELAS eS dae 38
TEMES EOME sales tcc acide taste quatnse:Gaciedy visu teptenesnbwel mul las deacrtadebiis a dylbhea dened aoa 38

SO GSO]: cece a vere. sesece aiterse ce airy 6 teeth terran tile te bere at yea aE a eae aT a 38
GYPSUM: « sees emesis 2 Ss Gee ee et cu HEE ae Fo ese Ae ew 39
Clay 3 sage tieiers ease dese sey ee eR ee eee ee eee Se 39
CO nk Ache Ge eh RE RR RRR ee ER Pee ecensninis 39
SOMO? CTS OSES ere age chibi es fn ce WAN odie ten ec gird noeBanhoncRes Lillia eae bietv tao coma a 40
La. Laz “mine” 2 sag5 gn wae eee RR eG EO BE Pee 40
Kleinwort DPrOSPECE. os4 wm se wee hes Soe aS OR RL ee 4l
MONTEZUMA. PFOSPECE. aoc scec soe cee HERES Baw eee Ee Es 41
Conclusions on ore deposits ........... cc eee eee eee ee 42
Water TESOURCES! Sis wos aoe cuca pes a pom weiss ae wale a igre Rash eHe tee SAUD 42
SCO UIS 6. us Gy Sie SARE EEE ESE REESE ORS SRO UE RS EE ER 42
SPLINES: coc scaccnewithe ach BES ES ES SS eS ee ees Syne Rae Boa 42
IWAECT ED OME docs. sevcish asous:souing.d iancepstuptie! & Dexa} omarsabess eerecaptutnsat ldmnde? aulaaheanciaes, 43

Indext 20 paaeg<x gs spaje te Seg a gh gle acah se Ae erin’ eral a nw Bea RW He i denarii 45
6 GEOLOGY OF

connection with an area farther south. C. L. Herrick in his
description of the geology of the San Pedro quadrangle refers
to the Sandia Mountains in considerable detail.

THE PRESENT WORK

The field work for this report was done in June and July,
1921. Light camping equipment was carried in an automobile,
and carps of several days’ duration were made at various
places at the foot of the mountains. While extreme precision
cannot be claimed for all the measurements and locations, it
is believed that the essential points are relatively accurate. In
an area so minutely disarranged structurally, it was impractic-
able to attempt a complete representation of the structure, and
most of these minor features are not shown on the map. The
elevations for the structure sections are modified from topo-
graphic maps of the United States Geological Survey. The ele-
vation given for Sandia Peak is from ‘‘A Dictionary of Alti-
tudes’’ (Bulletin 274, U.S. G. 8.). The elevation of the same
peak is given on the San Pedro topographic sheet as about 200
feet less.

The area affords many intricate problems regarding the
origin of structures and formations. These will bear much de-
tailed and careful study before satisfactory solutions can be
reached. The present report is contributed toward the ultimate
sum of knowledge pertaining to this area.

GEOGRAPHY
LOCATION AND AREA

The area under discussion lies in the northeastern part of
Bernalillo County, and the southeastern part of Sandoval Coun-
ty, New Mexico. It is about 8 miles from the eastern bound-
ary of these counties and is mainly within the limits of the San
Pedro topographic sheet.

The length, north and south, is 20 miles. Its width is 9 miles.
Of this area, fully 140 square miles is mountainous. The extent
of the area is shown in Plate I.

GEOGRAPHIC AND STRUCTURAL RELATIONS

The Sandia Mountains form the northern end of an uplift
east of the Rio Grande, extending southward more than 70
miles. To the east, at the northern end of this general uplift,
lies the series of igneous masses embracing the Cerrillos, Ortiz,
San Pedro, and South mountains. Farther south stretches the
THE SANDIA MOUNTAINS 7

great plain of the Estancia Valley. On the west, the range is
bordered by the mesa, sloping toward the Rio Grande Valley,
6 to 15 miles away. Northward, to the Rio Grande and Galisteo
Creek, the surface is deeply eroded and forms a badland type
of topography. «

The structural relationship to the Sandia Mountains of the
adjacent areas is disclosed wherever Cretaceous, or earlier,
sediments come to the surface. These rocks are much disturbed.
Tertiary and later deposits, such as those forming the mesas to
the west, lie comparatively level upon and conceal the older
structure of much of the surrounding country. (Fig. 1.)

The name Sandia (Spanish for watermelon) is said to have
been derived from the streaked appearance of the sedimentary
rocks forming the upper part of the range, as seen from a dis-
tance. This horizontal banding is due to alternate layers of
hard, precipitous, light-colored rocks, and shales which sup-
port a growth of evergreens. A more likely origin of the name
is found in the former growing of watermelons in the little
villages along the foot of the mountains north and east.

Prospecting has been carried on in the Sandia Mountains for
the past 70 years. No developments of established commercial
value have yet been made.

Lying within easy access of Albuquerque, these mountains
afford many places of resort for healthseekers, summer vaca-
tionists, and holiday parties. Whitcomb Springs has long been
a favorite retreat. Lorenzo Falls, Tejano Canyon, Ellis Ranch,
Bear Canyon, Hodgotite Canyon, each has its peculiar attrac-
tions. In Cienega Canyon, one of the most attractive, a camp
for Boy Scouts has been located by the Rotary Club of Albu-
querque. Well Country Camp, founded through the efforts of
“‘Larry’’ Glasebrook, is proving the possibilities of the region
for the healthseeker.

FORESTATION

The Sandia Mountains are an important part of the Manzano
National Forest. The west side of the mountains is relatively
bare, as seen from a distance of several miles. But even here
the deeper canyons and some of the upper slopes of the moun-
tains are well covered with trees. (Plate B.) The east side of
the mountains is distinctly different in appearance and in the
amount of timber. While some of the eastern slopes produce
nothing but a scrub growth of Jocust and oak, the greater part
is forested with red cedar, pinon, western yellow pine, white
8 GEOLOGY OF

fir, Douglas fir, aspen, and spruce. These occur in about the
order named, from the foothills to the higher peaks. A consid-
erable proportion of the fir and pine is timber 2 to 3 feet in
diameter. The heaviest forestation occurs on the east slope of
the highest, or northern, part of the range. No logging is being
done at present. Former logging operations have removed the
more accessible and better timber, the large trees now standing
being somewhat scattered and remote. The most important
species, from the standpoint of present utility in the surround-
ing territory, are the pinon and cedar. ,

CLIMATE

The climate is similar to that of other mountains in central
and southern New Mexico. A marked difference exists be-
tween the climatic conditions of mountain and mesa, and be-
tween the east and west sides of the mountains. In summer,
showers occur on the mountains almost every day, but they are
usually of short duration. The more torrential showers sweep
immense boulders down the canyons and deposit them along
the arroyos at the edge of the mesa. The flood waters of the
arroyos may reach to the river, but much is absorbed by the
gravelly soil of the mesa and continues its course underground.

The occurrence of the summer showers is directed largely
by the mountains, towards which air currents move during the
warmest part of the day. These showers usually ‘‘come up’’
from the east or the southeast, and the east slope of the moun-
tains receives the greatest rainfall. Thus in respect of move-
ment the showers differ from the thunder-storms of the Great
Plains region, where the direction is usually eastward.

In winter, heavy snows usually fill the higher parts of the
mountains. The mesa is generally free from snow, excepting on
northward slopes, where it may remain for several days.

In all seasons of the year the difference between night and
day temperatures is relatively wide. The nights are always
cool, while the mid-day sun strikes with great intensity, on ac-
count of the dryness and the clearness of the atmosphere. Win-
ter temperatures are rarely as low as 20° below zero and
summer temperatures do not often rise above 95°.

The following tables give conditions of temperature and
precipitation for several years at Cedro Ranger Station, Tijeras
Canyon. No record of humidity had been kept at this station
but the record is given for Albuquerque for 1920. This record
was taken at the State University, 16 miles west of Cedru
THE SANDIA MOUNTAINS 9

Ranger Station, at the edge of the mesa, and 1,300 feet lower.
For comparison, a similar record is given for Indianapolis for
the same year.

Weather record of Cedro Ranger Station, Tijeras Canyon, N. Mex.,
1915-1918 and 1920.
Precipitation (inches)

 

Jan, Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
1915..2.18 1.43 0.74 3.41 0.89 0.09 2.24 2.19 3.25 0.19 0.32 1.01 17.94
1916. .4.67 0.20 2.33 1.37 0.85 0 3.50 1.52 0.20 3.45 0.06 0.15 17.80
1917..0,79 1.10 0.12 0.50 0.70 0.21 2.99 1.24 1.22 T 0.06 T 8.93
1918..1.68 0.49 0.74 1.52 0.89 2.00 2.28 2.26 0.85 2.14 0.80 2.02 17.67
1920..1.51 0.98 0.62 0.63 1.20 0.16 0.384 2.07 0.41 2.01 1.08 1.08 12.09

Mean..2.17 0.84 0.91 1.49 0.81 0.49 2.27 1.86 1.19 1.56 0.46 0.85

 

Temperatures (degrees Fahr.)

 

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
1915... ... .... «.... 49.7 53.8 64.9 68.6 66.4 59.8 48.7 387.6 31.4

1916. .32.4 87.4 44.8 48.2 55.4 65.4 69. 668 60. 51. 36,5 28.4 49.6
1917..28.5 84,8 36.8 42.7 45.4 64.3 70.8 70. 65. 51. 39.6 35.2 48.7
1918..28.2 35.6 44.2 47.5 545 67.4 69.4 66.6 61.6 49.2 31.4 21.2 48.1
1920..30. 37.7 37. 41.9 55. 62. 67.9 64.2 59.8 45.8 86.6 29.2 48.9

Mean..29,.8 36.4 40.7 46. 52.7 64.2 69.1 66.8 61.2 49.1 36.3 29.1

 

 

Highest and lowest temperatures (degrees Fahr.)

 

Highest Lowest
Amount Date Amount Date
TOMS acs 3 a tevemenrr te aeleetecs es cute Sapa aN ek AON AL as ad ae 94 July 4 —10 Dec. 28
MOTO oid encsssassvacsesprcvingta ts 8 Seb: oped Geeishisl dep teed Eales ails 95 July 1 —6 Dec. 9
MODY oy 5. 8 Ase da sched haley thet Sasa dale bavi cena Aes 96 July 14 —10 Feb. 16
LOLS id crarivinany Ake anion aNaNinla dg eR 92 June 26 —19 Dee. 25
LO 20s sn aeketres ek KEES aS pea Sys eee 92 July 9 —20 Jan. 9

 

 

< Last in spring First in fall
TOUS 6 as ene Aen s ae Se eee Rls Be eS A eee May 4 Sept. 27
DOG 5d oc5 oticrcanccmisn Sarai ninemvannieeee oo eater May 27 Sept. 29
DA Ties, tisc0 5 totoepeccctysi, 208 ato Coed captin ates setgd. gee Monedaeman ators June 3 Sept. 27
EQS has ose compte ance gra Pes apie alegien peta S26 NOIR June 1 Sept, 29
WQS O ee. ia 0 2 2 saniaetent hse Ay oon Reeser & Gi at hoes Ane No og May 7 Sept. 23

 

Relative humidity, per cent, at Albuquerque, N. Mex., 1920

 

Jan, Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec, Year
Mean, a.m...79.4 73.9 57.5 56.9 56.1 59.9 58.4 70.4 60.3 58.8 69.7 70.5 64.3
Mean, p.m...51.3 43.0 27.9 26.4 23.4 30.2 27.3 37.1 30.4 33.4 44.0 43.3 34.8

 

Relative humidity, per cent, at Indinapolis, Ind., 1920

 

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec, Year
Mean,a.m... 86 84 75 76 70 75 74 80 82 76 79 83 178
Mean,p.m... 75 72 62 67 52 55 58 60 59 52 68 78 63

 

ACCESSIBILITY

The Sandia Mountains are easily reached by automobile, be-
ing about 10 miles from Albuquerque. A good highway leads
from Albuquerque to the mountains and through Tijeras
Canyon. A fair road leads as far as San Antonito and Tejano
Canyon. Access to the north part of the mountains is had from
10 GEOLOGY OF

Bernalillo, whence a fair road leads as far as La Madera, by
way of Placitas. The road between San Antonito and La Ma-
dera is not suitable for automobiles. Several roads lead across
the mesa to canyons on the west side of the mountains. Bear
Canyon is thus approached from Albuquerque, 13 miles distant.
These ungraded mesa roads remain smooth and hard through-
out the year. Roads have been prepared into the mountains
at the several resorts. The United States Forest Service main-
tains marked trails over the mountains, making traverse pos-
sible to people afoot or on horseback. Numerous springs add
to the convenience of mountain-climbing.
INDUSTRIES

Differences in climatic conditions between the two sides of
the mountains are reflected in the different pursuits of the in-
habitants of the two regions. The population is predominantly
—almost exclusively—Spanish-American. For many years the
flat and fertile patches of valley along the arroyos to the north
and the east, and in Tijeras Canyon, have been more or less sub-
ject to cultivation. Corn, beans, and wheat are produced; part-
ly with the aid of irrigation, partly without it. Apples and
other fruits are raised to some extent. Goat-raising adds to the
income of the small farms.

At the west side of the mountains no farming is carried on.
To the casual observer traveling the highway several miles
from the mountains, any sign of a habitation, is scarcely notice-
able on the wide stretch of mesa sloping gently down from the
mountains’ edge. One does not imagine that any human being
would desire to make a home on the barren mesa or in the rug-
ged face of the mountain. Closer observation reveals the pres-
ence of many a little dwelling tucked away in some secluded
canyon, or at its mouth, its color blending into the gray of the
surrounding landscape and shielding it from notice. These are
the homes of the goat herders and the sheep herders. A flock
of 200 goats yields almost the sole sustenance of the family—
meat, milk and cheese. In some cases a small vegetable garden
is attempted. Water is supplied from a canyon spring. Over
the rocky sides of the mountains the flock clambers by day, re-
turning to the little corral at night. Cattle roam at will over
the east slope of the mountains and clear to its summit.

To some extent the native farmers increase their income by
collecting dead timber from the National Forest and hauling it
to Albuquerque, distances of 15 to 25 miles.
U.N. M. Bulletin 108, Plate II.

 

 

 

 

 

A—Tijeras Canyon, northeast from the quartzite ridge.

 

 

 

 

 

B—Edge of Sandia Mountains, looking south from the mouth of Embudo Canyon.
The granite mass in the center partly hides the limestone outcrop beyond.
12 GEOLOGY OF

TOPOGRAPHY
Relief

The main topographic features are a mountain range and its
bordering foothills and mesa. Viewed from the west the San-
dia range presents a smoothly irregular sky-line arching to a
height of 2,000 to 4,000 feet across some 18 miles and descend-
ing to the general level of the adjoining mesa. At the base of
the range on the west the mesa slopes away at an angle of
10° to 15°, but gradually decreasing to the valley of the
Rio Grande. The south limit of this range is Tijeras Can-
yon, which cuts through the general uplift and separates the
Sandias from the Manzano range. A portion of the latter
range is indicated on the map and is described in this report.
(Plates I and II.)

The west front of the range is very rough and its margin is
separated by many canyons. The upper limit is marked by a
precipitous face of rock having a slope of from 45° to
nearly vertical for a distance of approximately 1,000 feet de-
scent. The rim is very distinct, and the ‘‘roof’’ of the moun-
tain slopes gently away to the east. The mass of the mountain
westward from the abrupt descent is an almost indiscriminate
arrangement of peaks and irregular ridges intensely cut by
erosion. Very little soil is able to cling to the steep and rocky
surfaces.

Toward the north end of the range a spur is given off, which
curves southward forming a hook. This part is called Rincon
(meaning angle or corner). The western edge of Rincon Moun-
tain has few long canyons. A talus of boulders washed from
the steep slope extends a quarter of a mile out on the mesa.

Along the middle and southern portions of the western edge
of the Sandias the mesa deposits are much finer and the slope
is more gentle.

The east side of the Sandia range has a general slope of 10°
to 15°. Compared with the western side of the mountain
it is rather even and regular. At a distance, it appears like
a great roof. (Plate III, B.) There are, however, many sub-
ordinate uplifts on this broad slope, caused by faulting. A
series of faults approximately parallel to one another, with
strikes nearly at right angles to the rim of the mountain, have
given rise to a series of canyons running down the slope. Fault-
ing parallel to the rim has also occurred, forming local uplifts,
U. N. M. Bulletin 108, Plate III.

 

 

 

 

 

A—North end of Sandias, looking southwest across Placitas.

 

 

 

 

 

B—South end of Sandias, looking north across Tijeras Canyon,
14 GEOLOGY OF

like Palomas Peak. The surface, for the most part, is soil-
covered and forested.

Toward the base of the mountain, on the east side, the sur-
face is much broken and upturned by minor faults. Among
these hills are limited areas of relatively level land.

The north end of the range reaches down, through a border
of upturned and northward-dipping strata, to the general level
of the ‘‘badland’’ country between the Rio Grande and Galisteo
Creek. (Pl. III, A.) Montezuma Mountain, a structural frag-
ment of the main Sandia range, is the most northern extension
of the uplift.

The south end of the Sandias drops rather abruptly, and with
ragged surface, to the level of Tijeras Canyon. South of this
canyon the mountains are not so high, but there is a somewhat
similar arrangement of topography.

What seems to be the remnant of an ancient base level is
found to the west of the mountains between Embudito and Pino
canyons. Here in a strip half a mile wide the granite rocks
are planed off relatively even and level. There is very little
soil above the rocks and they are bare in a number of places.
The surface is trenched to a depth of a few feet by the arroyos
leading from the mountains but these water courses seem to
be only the beginning of a new cycle of erosion. This erosion
surface, or terrace, may extend all along the west base of the
mountains and even farther out under the mesa deposits, but
this cannot be known readily, on account of the thick deposits
of talus next to the mountains for much of the distance beyond
the limits given. Similar eonditions do appear for 1 or 2
miles north of the road leading into Tijeras Canyon. In marked
contrast to this surface are the rugged slopes of the mountains
that rise abruptly above it; and yet, both surfaces seem to be
formed on the very same kind of rock.

On account of the form of this surface and its relation to the
general mass and shape of the mountains, it is concluded to be
the result of erosion and not of uplift or deformation of the
earth’s crust. It is a topographic feature of considerable in
terest, in that it arouses speculation on the order and duration
of geologic events connected with the building of the Sandia
Mountains.

Drainage

The main channel of erosion in the area is Tijeras Canyon.

This canyon has been sawed through the uplifted edge and core
THE SANDIA MOUNTAINS 15

of rocks nearly transversely. It is now the outlet for about
one-third of the drainage of the area. It is being rather rapidly
deepened, under the scour of the frequent summer torrents.
During ordinary conditions a small stream from mountain
springs flows above the gravelly bed, with frequent interrup-
tions, out to the edge of the mountains. (PI. II, A.)

Canyon de las Huertas follows a fault line for 5 or 6 miles
nearly due north. It is perhaps the most picturesque canyon in
the mountains, being shaded for several miles and carrying a
clear mountain stream most of its length. This canyon has been
a favorite with many campers, but the road leading along its
course is somewhat difficult for automobiles.

Bear Canyon is frequented by automobile parties from Albu-
querque. It has a small stream, that reaches the mesa over a
16-foot fall.

Nearly all the canyons contain springs, which flow at the
surface of the canyons or underground through beds of sand
and gravel. The springs on the east slope carry much carbonate
of lime, since they originate in the cavernous limestones which
cover that slope. These springs also are more copious, as well
aS more numerous, than those on the west side. Deposits of
ealeareous tufa occur where these waters emerge, but no such
deposits are noticeable from the spring waters of the west side
of the mountain.

DESCRIPTIVE GEOLOGY

STRATIGRAPHY
Sedimentary Rocks
The sedimentary rocks exposed in the area represent the
Pennsylvanian, the Permian, and the Cretaceous systems. De-
posits of Pleistocene and Recent gravels also occur - The largest
area of these rocks is that of the Pennsylvanian. Tertiary de-
posits appear in the surrounding mesas.
THE PENNSYLVANIAN-PERMIAN
The sedimentary series overlying the granite core of the
Sandias and underneath the Cretaceous beds were regarded
by Herrick! as embracing two systems. The lower of these two
systems he calls Carboniferous, largely made up of limestones.
The upper formation, characterized mainly by its red color, he
assigns to the Jura-Triassic. He asserts, however, that he had

 

1 Herrick, C. L., Bulletin of the Univer. of N. Mex., Vol. 1, pp. 104, 105, 108,
109, 115, 116, 1899.

{
16 GEOLOGY OF

found no fossils in these red beds, by which their stratigraphic
relationship might be established.

In a later discussion of the formations, Herrick’ refers to the
presence of Permian fossils in a ‘‘quartzite near the base’’ of
the Manzano group. He here suggests that the two upper sub-
divisions may represent the Triassic and Jurassic.

Lee? states that he found Pennsylvanian fossils in the lime-
stone overlying the red beds of the Manzano group, and ac-
cordingly referred this group to the Pennsylvanian. This lime-
stone (the San Andres) does not appear in the Sandia Moun-
tains section, but the rest of the series is represented here.

Boese’®, after a careful study of a collection of ammonoids
from the shales in the lower part of the Abo sandstone near
Tularosa, concludes that the Abo beds belong to the Pennsyl-
vanian. He also found in the same horizon near Pecos village a
number of brachiopods and peleecypods, not one of which was
a Permian form.

Baker?, having studied a large portion of New Mexico east
of the Rio Grande, found a widespread erosional unconformity
(often an angular one) between the Magdalena and the Abo
formation. He would group the Abo with the Pennsvlvanian,
and the Yeso and San Andres with the Permian.

‘Lee’ later accepts evidences which place the division be-
tween the Pennsylvanian and the Permian at the base of the
Manzano. In a review® of the papers by Boese and by Baker,
he calls attention to the inappropriateness of placing the bound-
ary between the two series 200 feet above the base of the Abo in
perfectly conformable strata.

The present attitude of the United States Geological Survey
is to regard the unconformity at the base of the Manzano group
as marking the boundary between the Pennsylvanian and the
Permian. This classification is definitely set forth by Darton?
in a recent bulletin of the United States Geological Survey. His

 

1 Herrick, C, L., Geolo of the white sands of New Mexico: i
Univ, of N. Mex, Vol. 2. pp. 4 and 5, 1900, a igen ere
2 Lee, T., and Girty, G. H., The Manzano grou of th i 7
No Meee U.S: Gaol. Survey’ Bull, 880, 1s lgoe TES Valley,
3 Boese, Emil, On ammonoids from ihe Abo sandstone of New Mexico and th
aoe the beds which contain them: Amer. Jour. Sci., Vol. 49, No. 289, pp. 51 62
4 Baker, C. L., Contributions to the stratigraphy of eastern N
Jour. Sci. Vol, 49. No, 290, pp. 99-126, 1920. Pa ROTOR Ae,
5 Lee, Willis T., General stratigraphic break between Pennsylvanian oe Permi-
an in western America: Bull. Geol. Soe, America, Vol. 28, pp. 169, 170, 19
6 Lee, Willis T., Notes on the Manzano group, New Mexico: Amer. Te Sci.,
Vol. 49, No, 293, pp. 324, 325, 1920.
7 Darton, N. A, Geologic structure of parts of New Mexico: U. 8. Geol. Survey
Bull. 726 E, pp. 175- 182, 1922.
THE SANDIA MOUNTAINS 17

classification is based on fossils identified by David White and
G. H. Girty. Darton’s classification and Lee’s former classifi-
cation are placed side by side below, for comparison.

Paleozoic Formations in the Sandia Mountains

 

 

 

 

 

 

Darton Jj Lee Darton Lee
Age Group

Permian |" Manzano ee

San Adres limestone
Manzano Yeso formation

Pennsyl- Magdalena Abo sandstone

vanian Magdalena Madera limestone
Sandia formation

 

 

Mr. Darton thus combines the Yeso formation and the San
Andres limestone of Lee’s earlier classification into one sub-
division, for which he introduces the name Chupadera. The
Abo sandstone may usually be distinguished by its red color, its
uniformity of texture, and its massive structure. It is wide-
spread in New Mexico and is said to be generally unconform-
able to the Magdalena. The Chupadera formation therefore,
now includes the sandstones, shales, and gypsiferous beds just
above the Abo sandstone, and the massive limestone typically
shown capping the Chupadera Mesa.

The Magdalena Group

The rocks of the Magdalena group are prominently displayed
along the rim of the Sandias. They consist largely of lime-
stones, but there are also thick beds of sandstone. In general,
the limestones are the uppermost rocks of the formation. The
following sections show the succession of strata at different
places in the area.

Section of rocks about 2 mlies southwest of the north end of the
Manzano Mountains, about 1 mile south of Tijeras Canyon.

Feet

Limestone, bluish gray, sandy, fossiliferous; fossils
especially abundant 40 feet from top............. 140
Sandstone, COarse, SPAY ices -o6 ccie a ese ale ee deans ies bla gansia wee oece 55
“Porcelanite,” red to brown (local)..............-0 eae 15
BIMeStOn es. “SLAY sss oe eee Rh ee et eee eae ah 40
Hornblende schist, greenish gray................000-05 500

The upper limestone is the rim rock on the ridge of the Man-
zano Mountains, here.
Section at South Sandia Peak.

Feet

Limestone, massive, very siliceous (or cherty) at top.. 95

Limestone, shaley or thinlbedded, very sandy, fissile.... 15
Talus slope covered with small pieces of siliceous

shaley HmestOne c4 50005 kske eer ied eben ede eae gm 85

Sandstone, about like next lower sandstone bed....... iL,
18

GEOLOGY OF

Covered ....... eae jasbead tant mice ces Sadia esate aD ha ANH nia ipze 2 sont onic 16
Sandstone, greenish to grayish, rather ‘‘rotten’”’....... 3
COVERS iiaG ci asecadk signa sis U aia es Garey a aot es, 3 25
Sandstone, coarse, brownish to chocolate-colored,

ClifP=fOnIMING? oeivacs audteslel hOGA Wee we Seiad Sher Uae 10
Conglomerate, coarse, pebbles about 1 inch in

uiameter, and mostly quartz ....-...-- eee eeeee 2
Conglomerate, fine somewhat quartzose in places..... 18

Great unconformity

Granite: .oy20de See eRe ONS EEE aS Bae B ree s 1,000

Section about half a mile north of upper steel bridge in
Tijeras Canyon.

Feet
Sandstone, coarse, greenish-gray.................0. 404
Conglomerate, with pebbles about one-half to one-

TOULTD dmch GISMiCley «. .ce caw ia Kea e eee sehen de 22
mandstoie, CHocelate-brOwWN < cis scbaradarnceoeewa oe 8
COREIOMIEIAe 6c 4 wlcd oda RO be Bie be Dee ew eek di
Sandstone, chocolate-brown, smewhat fissile........ 8

Sandstone, hard, coarse, dark brown, somewhat
‘ shaley and cross-bedded ..............2.00008 4
Conglomerate, coarse; some places contain brown jas-
peroid gravel about a quarter of an inch in di-
ameter, cemented in a matrix of white chalce-
dony; boulders 2 feet in diameter, of the under-

lying formation, at the bottom................ 10 to15
Great unconformity
Gneiss, schist, and quartzite ..................00. 250

Section on Montezuma Mountain 1 mile east of Placitas.
Ft. In.
Limestone, from top of escarpment on Montezuma

Mountain ......... UR Sag GAO Nee ec en ESA ae uaa dle 450 0
Shale, greenish, sandy............. ccc eee eee ee eevee 0 10
SAMASEOME® seals 5. Sse sgsehias ne eee we AS a aa tuisltalien dia ee ta nis bhiace eee 2 0
Shale, DPurplish: ‘s.-4 i125 44 4d. ee SE aw eel ed BA EES Soin 2 0
Sandstone, gray, weathering to brown ............. 9 0
Sandy shale, grayish to purplish ................. 0 10
Paridstone, PrOWNISH gig si vaceve ea beeen ove aya 0 10
Sandy shale, gray to brown ......... cece cree e eee 3 0
Limestone, nodular, fossiliferous, and some sandy

WTVAPO VITA jescice oye dA a A ytecey a thos 4 RR abe aden & away tna arn kee 20)
Sandy shale, fissile, gray, weathering brown.......... 5 0
Sanstone, coarse, gray to brown, lower 5 feet quite

massive, upper portion rather shaley ......... 23 0
Sandy shale, fissile, purplish, weathering brownish,

aislly erodeG: wid Me ane ease ts ase a toda: ews eta Re 6 0
Sandstone, coarse, hard, weathering to a dark brown-

ASH: VAM sg Seed a eld ees OMG Siete imieee . : 6 0
Sandy ‘Shaler. .cas ate ge wos aes sew a aeea gas deen Sis heawee 5.
Sandstone, fine, in lenses in shaley sandstone...... 3 6
Sandstone, coarse, weathering brownish black, forni-

ing cliffs, cross-bedded ......... ee esses eee eens 10 0

Limestone, bluish gray generally, but with phases of
fissile calcareous shale highly charged with hema-
tite, weathering rough ............e0+. eee 30

CHEK. 2.34% ets eee eve ds weds 0 Spase enti a esha ae ea ve reoereeeee se OF Qug
THE SANDIA MOUNTAINS 19

LIMeCStONG, oan won gece ¥ate ec dence: Was sila a tea cart a cee ed 0 6
CHORE 2. vace-ciace ya yscbotn a datas Sicecy ance tek we deaeayeesoyevks dd americans 0 3%
Limestone, gray ..... 0.00. ccc ccc ce cece cee nens 15 0

Limestone, nodular, “bastard,” in layers from a few
inches to a foot thick, embedded in a purplish

or greenish sandy shale, growing more sandy to-

‘Ward the ‘bottom gifs ya vs wes oeeasad ence sebesiace 12 0
Shale, chocolate-colored ........... 00. ce cece ceeeeas 1 4
Sandstone, coarse, greenish or purplish, weathering’

out in rounded pieces a few inches diameter,

growing course downward ................000- 5 60
Conglomerate, rather loosely cemented,. pebbles 1 to

2 inches diameter, mainly of white quartz little

eroded, in a matrix of greenish to purplish sand 4 0
Unconformity , ;

Schist, purplish and greenish, contorted, schistosity
dipping 45 degrees S. W., containing lenses and

veins Of White Quartz 2.0.0.4 cic ea cae dean eee eee 120 0
Section about half a mile northeast of Whitcomb Springs.
Feet
PAINE SLOME: ae or tio a dons ie ene iotesh uted suas: Macnaeuee eden Bho 200
Sandstone, coarse, gray, cross-bedded .............. 6 to 18
Limestone; siliceous) 9.43.46 oes gw bb a Ree ew as 6
Mamidy SHAS) ae see os ce iw des Rodin qeantond de snd s levetadiadas 3 Steen dive 5
Sandstone, calcareous, coarse, almost conglmeratic. . 12
ATO SS ING) WE: acy en de nae nee Le Oh ae aS ey 9
Sandstone, coarse, somewhat rotten ...............- 10
Sandstone, calcareous, coarse, growing more calcar-

COUS MO WIWATG. ess cieenecai aleve nbaes oe evi, onerye 8 RRR aca Bs 15
LWieetOne. Car BVA 2s4 ky ye ek eas Seeew eed ees HESS 3
Sandstone, coarse, hard ............005 Feet ate elo hs enerationts 6
Limestone, blue, rather siliceous ...............4.5 14
Limestone, blue, fissile, some places shaley, growing

less fissile downward, very siliceous ............ 30
Shale and limestone interbedded, more or less hid by

LAMAN SE eyes cilereen caeieiier entsede rian dh inca eton deen eee attends AY aioe a Beare 60
Talus Slope of coarse boulders... 684404. e%¢5 es 6u84 4 70

A comparison of these sections reveals a uniformity some-
what as follows: At the top, forming cliffs along the whole line
of the Sandia ridge, as well as on the local uplifts on the east
side, is a limestone, from 100 feet to 450 feet thick. This lime-
stone is generally rather siliceous. This is followed by sand-
stones from 20 feet to 75 feet thick. In some places certain
beds of this sandstone series are cliff-forming. In many places
limestones occur below these sandstones, ranging from 6 feet to
60 feet in thickness. These lower limestones are more thinly-
bedded than the upper series and, as a rule, are more siliceous.
Shaley sandstones frequently intervene. The basal series is
usually a coarse conglomerate and sandstone, comprising beds
from 10 feet to 20 feet thick.

In some places the limestone beds seem to lie directly upon
20 GEOLOGY OF

the eroded schists. In other places about 100 feet of con-
glomerates and sandstones make up the entire body of sedi-
ments, lying unconformably above the metamorphic series.

These conglomerate beds are largely composed of fragments
of white quartz, the remnants of the eroded metamorphic series
which they overlie. White quartz, in lenses and layers in the
schistose rocks, is very abundant.

The limestone of the upper series is thick-bedded, and some
parts of it are so thoroughly massive that it is difficult to detect
any planes of bedding. The thick ledges form many steep cliffs
along the upper part of the Sandia range, while the interven-
ing shaley and easily disintegrated beds furnish slope and soil
for the strip of vegetation clinging to the western front. (Pl. IV,
A.)

The weathered surfaces of the limestone are usually very
rough, owing to the included grains and masses of silica. Some
of this roughness is due to outstanding grains of sand, or fine
particles of precipitated silica. Nodules of flint several inches
in diameter cover the surface in some places, especially at the
top of the mountains, where wind and rains have kept the rocks
bare. From a considerable portion of the south end of South
Sandia Peak the upper limestone has been eroded, leaving a
rim-rock of sandstone. These rocks comprise what Herrick?
has called the Sandia formation. Characteristic fossils of lower
Pennsylvanian age are abundant in the limestones. Herrick?
has identified 14 species of brachiopods, 8 pelecypods, and a
number of bryozoans. Crinoid fragments abound in some of
the beds, and rocks containing Fusulina were found at the top
of Palomas Peak.

The Manzano Group

Overlying the Magdalena group uneconformably is a thick
series of red beds. The latter seem to have been laid down after
the main Sandia ridge and the earlier Pennsylvanian strata had
been partly raised above the sea. These beds occupy structural
valleys in the older formation and appear to be separated from
that series by a surface of erosion also. Places of actual con-
tact are difficult to find. The red beds series lies outward from
the Magdalena group on the east and north sides of the moun-
tains, being in turn succeeded by the Cretaceous.

The series consists of brownish red shales and sandstones, 100

 

1 Herrick, C. L., Geology of the white sands of New Mexico, Bulletin of the
Univ. of N. Mex,, Geol. Series, Vol. II, part 1, 1900.
2 Op. cit.
THE SANDIA MOUNTAINS 21

to 300 feet thick. These beds form the foot-hills on the north
and east sides of the Sandia range. They are much broken
by faults, the upturned stata forming innumerable hog-backs,
and in some places the dip is vertical. Fossils are not often
found in these beds.

CRETACEOUS ROCKS

Overlying the red beds, apparently conformably, is a series
of light-colored sandstones, with intervening beds of bluish-
gray shale. The sandstones in some places are almost white.
The degree of consolidation varies considerably. In the vicin-
ity of Placitas, some of these beds are very incoherent, easily
weathering down. About a quarter of a mile northwest of San
Antonio this sandstone outcrops in a very coherent phase, in
some places almost a quartzite.

The series is coal-bearing in certain localities within | the
area. Coal outcrops occur near San Antonio and at Placitas.
It is in this series that the great bodies of coal in' this State
oceur.

The Cretaceous beds at the north end of the Sandias are
easily distinguished since their color is in marked contrast with
that of the red beds outcropping toward the mountains, In the
vicinity of San Antonio the contact of the Cretaceous with the
red beds is not so noticeable, owing to the great amount of local
disturbance of the strata.

At Placitas the broad, relatively level area in which that vil-
lage is located is probably underlain mainly by truncated beds
of Cretaceous sediments. Overlying these is 20 to 40 feet of
alluvial soil. (Pl. III, A.) Around San Antonio the tops of
certain high hills are composed of gray Cretaceous sandstones.
The lower and more level areas between San Antonio and San
Antonito, which are devoted to agriculture, are largely under-
lain by red beds.

The Cretaceous area east of the Sandias occupies the upper
part of a structural basin, the center of which lies outside the
present area. The road from San Antonio to San Antonito lies
nearly along the west edge of the Cretaceous beds. Lee! assigns
the coal-bearing rocks of this vicinity to the Mesaverde.

Igneous Rocks
GRANITE

The characteristic igneous rock is a coarse porphyritic gran-
ite. This type occurs all along the western front of the main

1 Lee, W. T., The Tiperas coal field, Bernalillo County, N. Mex., Bull. U. 8.
Geol. Survey No. 471, 1912.
22 GEOLOGY OF

ridge of the Sandias and it is the core of the uplift. It forms a
belt from 2 to 4 miles wide, with the wider portion at the south.
For the most part, the eastern limit of this belt is the escarp-
ment of Pennsylvanian rocks forming the ridge of the moun-
tains. Its western boundary is rather sharply marked, where
it meets the relatively level surface of the mesa. The western
margin of the granite belt, which is the edge of the mountains
for most of the distance, somewhat corresponds in direction to
the edge of the escarpment. At the north end of this belt, for
a distance of 5 miles the granite does not form the mountain
boundary; but its contact is with a metamorphic series, which
extends the limits of the mountains 1 to 144 miles farther
west. For several miles along its southeastern margin the gran-
ite belt joins another series of metamorphic rocks—a different
type from that on the northwest border—which continues south-
westward beyond the limits of the present area. (PI. I.)

The general appearance of the granite is a coarse, grayish to
pinkish rock, weathering very rough. Extreme age is suggest-
ed by the extent to which weathering and disintegration have
advanced. Curious black knots, or segregations, of a  fine-
grained material are scattered through the granite in some
places. These masses resist erosion and stand out boldly on the
surface. This feature is noticeable especially along the high-
way in the west part of Tijeras Canyon.

The rock is of a muscovite-hornblende type, with phenocrysts
of pink feldspar from half to three-fourths of an inch in dia-
meter. A fresh surface of the rock is very beautiul. The mica
being less resistant to weathering, and being first removed. al-
lows the granules of quartz to separate from around the feld-
spar crystals. Thus, on a weathered surface, crystals stand out
roughly. The dark-colored inclusions seem to be principally
hornblende.

The topography of the granite belt is very rough. It con-
trasts strongly with the surface of the eastern slope of the
mountains, where erosion has largely followed lines of faulting.
There the general surface is distinctly eastward, conforming
with the dip of the strata. Here erosion has operated for 4
much longer time. The original conditions directing the
agencies of erosion are no longer plainly visible. No doubt the
same, or similar, dislocations that appear on the east side have
occurred on the west, causing certain rearrangements of drain-
age lines. But, for the most part, the topography of this side
THE SANDIA MOUNTAINS 23

of the range is wildly irregular, the result of age-long disin-
tegration and erosion before and after the deposition of the
bedded rocks above the granite.

Some of the granite peaks are almost equal in height to the
highest parts of the rim-rock. Along the great fault zone, that
parallels the mountain crest, the manifest evidence of that dis-
location is a series of disjointed p'nnacles, precipitous for 1,000
feet, or more. (Pl. IV, B.) The rocks of this zone show less
weathering than do those other parts of the granite area, and
they have probably been exposed for a much shorter period.
The granite underlies all other formations of the area. Where-
ever schists are in contact with the granite, the latter is the
younger formation, having fused its way under or into the
pre-existing rocks. Frequently erosion has cut deeply enough
into the schists to expose the intruded rock.

In the case of the sedimentary beds, however, the granite
seems to have existed as an old, weathered surface before the
sediments were laid down. Successive uplifts of the granite
mass evidently took place afterward, raising the sedimentary
beds with it. Local uplifts, with faulting, have formed such
features as Palomas Peak and the ridge above Tejano Canyon.
At the base of these block mountain peaks there is usually an
exposure of granite. These exposures all have the character-
istic features of the granite forming the main core of the
Sandias.

Intruded into the granite in numerous places, are masses of
reddish-brown rock, more basic in composition than the original
granite. These intrusions in some places form isolated peaks
(Pl. II, B, center), while in others the intrusive has weathered
to relatively low rounded knolls. The weathering produces a
rather fine, reddish soil, in contrast to the usual gray gravel
which results from the disintegration of the coarser granite.

Mesa deposits of unconsolidated material rest upon the
eroded surface of the granite at the base of the mountains.
(Pl. II, B.) These deposits have formed from the disintegrated
material of the mountains, washed down by every shower and
ever accumulating on the surface of the mesa. Gravel and
boulders, some of them tons in weight, are thus deposited near
the mountains, while finer material is swept along the arroyos,
until it, too, is left by the decreasing force of the current.

Dikes of acidic granite cut the main granite mass in many
places. Along the western border of the mountains these dikes
24 GEOLOGY OF

commonly trend east and west. They vary in width from a frac-
tion of an inch to 40 feet and are usually less than 40 rods in
length. The dike rock is usually light colored and rather fine
grained, but pegmatitic phases occur.

BASALT

About half a mile northwest of Placitas a wall of basalt 20
feet thick extends in 2 northeasterly direction for about 1 mile.
It has a southeast dip of 80°. Near the middle of the dike
an offset occurs and the direction of the dike is changed
about 10°. At this point the dike is crossed by an arroyo
and has been eroded to a depth of 150 feet. The intrusion cuts
the Cretaceous sediments but seems to be overlain by the later,
unconsolidated, deposits. A narrow extension of this dike is
laid bare in the bed of an arroyo about a quarter of a mile be-
yond the western exposure. The east end disappears under a
hill of Cretaceous and Pleistocene deposits.

The rock is a common type of dense black basalt. No trace
of a surface flow is apparent. The Cretaceous sediments in
contact with the basalt are not materially changed on account
of the heat of the intrusion. While similar dikes occur in the
region surrounding the Ortiz Mountains, this is the only one
observed within the area of the present report.

Metamorphic Rocks
SCHISTS

Outcrops of schists and gneisses occur in several places in the
area. The largest of these adjoins the granite series in the north-
west part, forming the uplift known as Rincon Mountain. It is
about 5 miles long and 1 mile wide, with the longer axis trend-
ing about 25° east of north. This area joins the sediments
of the mesa on the south and west. At the north it is overlain
by the Pennsylvanian rocks.

The essential topographic feature is a mountain uplift, hav-
ing an elevation of 8,000 feet. The surface slopes in a general
way from this peak, which is approximately in the center of
the area. The mountain as a whole forms a sort of hook to the
main Sandia ridge, with the point toward the south. The area
between Rincon Mountain and the main Sandia range iy a
series of rounded granite hills traversed by drainage channels.
The west side of Rincon Mountain is very rugged and steep,
and an exceptionally large talus deposit of boulders has eol-
lected, which reaches for a quarter of a mile out on the mesa.

The rocks comprise hornblende and mica schists and gneiss.
THE SANDIA MOUNTAINS 25

All are much contorted. The general color is a dark greenish
gray. Dikes of light-colored granite are frequent along the
west side, cutting the schists transversely to the edge. The dip
of schistosity is steeply eastward, varying from 40° to 70°.
The series partly overlies the granite mass that forms the core
of the Sandias. It is thus evidently older than the granite and
has been raised to its present position by the intrusion of the
latter.

An area of hornblende schists lies to the west of the escarp-
ment of the Manzano Mountains just south of Tijeras Canyon.
(Pl. II, A, right side.) Emerging from under the Pennsylvan-
ian sediments about 1 mile west of Tijeras, this belt of schists
extends southwestward several miles, increasing to a maximum
width of 1 mile 2 miles south of Tijeras Canyon. Its northwest
boundary follows the line of Tijeras Canyon for 2 miles and
then, leaving that canyon, continues up a tributary canyon in
the same direction, beyond the present area.

The position of the series is immediately below the sediment-
ary bed forming the upper part of the escarpment of the Man-
zano. The contact with the next series to the west is usually
not distinet.

These schists are generally a dark greenish gray, and consist
essentially of hornblende. The portion lying nearest to the
series on the west is more basic and more schistose than the up-
per or east side of the area. The upper part also is harder, and
forms a prominent shoulder along the escarpment just below
the sedimentary series. Veins and lenses of quartz are numer-
ous, here and in some places the schists are largely quartzitic,
the banding much resembling the stratification lines in quartz-
ite. The dip of schistosity is 70° to 80° 8. E. The schists are
much crumpled.

Another area of metamorphic rocks lies on the west slope of
Montezuma Mountain, about 1 mile east of Placitas. This out-
crop is about half a mile long, north and south, and possibly 500
feet wide. It is just above the Huertas Arroyo. Red beds over-
lie the series at its base, while its upper part forms an erosional
unconformity with the lower beds of the Pennsylvanian.

The series comprises schists and gneisses, purplish to green-
ish, and much contorted. The whole series contains numerous
faults, and the outcrop shows certain repetitions on account
of the faults. Portions of the overlying sedimentary beds lie
in contact with the schists along fault planes.
26 GEOLOGY OF

The sedimentary beds immediately overlying are largely
composed of fragments of white quartz, not much water-worn,
derived from lenses of quartz which occur abundantly in the
metamorphic rocks. These fragments are imbedded in a matrix
of greenish to purplish-gray sand, the detritus of pre-existing
gneisses and schists.

A similar series of metamorphic rocks occurs a quarter of a
mile southeast of La Madera, in a canyon where a large spring
issues. The exposure continues only for a few rods. The rocks
are schists, much contorted, including a layer 10 feet thick
resembling quartzite. Below the schists 15 feet of granite is
exposed.

An unusual occurrence of white quartz appears near the
south end of Rincon Mountain. The rock is distinguishable at a
distance of 12 miles. Locally it is called ‘‘Pina Blaneca.’’ It
is like a wall, standing across the point of the mountain 200
feet above the mesa and extending eastward somewhat inter-
vittently for 60 rods. The most prominent exposure is 20 feet
above the surface and it is 10 feet thick. The deposit is like a
vein in appearance and is essentially pure, fine-grained quartz.
Portions of the vein are distinctly schistose, showing that meta-
morphic processes have operated since its original deposition.
In some respects this mass of rock resembles the quartzose ridge
that cuts Tijeras Canyon 3 miles below Tijeras. In other re-
spects it corresponds to the white quartz lenses and veins that
occur so abundantly elsewhere in the schistose rocks.

GNEISS AND QUARTZ SCHIST.

Lying adjacent to the green schists, that form the base of the
escarpment of the Manzano Mountains at their north end, is a
series of metamorphic rocks of several varieties. The general
topographic appearance of this series is a succession of low
peaks light-brown in color and usually of somewhat rounded
outline. The direction of the. series is about parallel to the
escarpment of the Manzano range to the east. The general
smoothness of outline of these peaks is broken by certain hard
obtrusive masses, that attam a predominant height in some
places. This belt is about half a mile wide. It extends from
within half a mile of Whitcomb Springs southwestward beyond
the limits of the present area. The series is rather easily dis-
tinguished by the peculiar rusty brown color of the surface.

The common rock of the series is a contorted gneiss. Tight?

 

1 Tight, W. G., Sketch map. Sandia Mountains excursion, G, S. A., 1907,
THE SANDIA MOUNTAINS 27

calls it a ‘‘fine-grained granite.’’ Herrick? refers to it as
‘‘metamorphie rocks like hornblende and mica schists and dio-
rite.’’ It has many local variations in structure and composi-
tion. The texture is indeed rather fine—much finer than that
of the granite series bordering it on the west. In some places
the gneiss is cut by basic intrusives or is so intimately asso-
ciated with other crystalline masses that it is difficult to tell
which is the rock intruded and which the intrusive. Some parts
are coarsely gneissoid, containing much greenish hornblende
mixed with pink feldspar Other phases are like granite in
texture and general appearance. There are also phases of dis-
tinct schistosity.

The composition is, in the main, basic. The rounded form
of the outcropping peaks and their brownish color are due to
the weathering down of the rock, in which process the iron of
the silicates appears as the hydrous oxide. As a rule the dis-
integrated material forms a thin mantle of soil above the
weathered rocks.

The series is much contorted in some places, and joints are
numerous. At the northeast end it is cut by a fault that ex-
tends southeastward from the rim of the Sandias. The upthrow
is to the north. This fault line has diverted erosion so that a
deep gulch has been cut across the series where it passes below
the sedimentary beds to the northeast. The contact of this
series with the green schists on one side and the granite on the
other is rather gradual. The line of contact with the green
schists is, however, rather distinctly indicated by the topo-
graphy.

The most prominent part of this series toward its northern
end is a steep and bare crest of quartzose rocks appearing
where the series plunges beneath the sedimentary beds and con-
tinuing southwestward 3 miles or more. South of Tijeras Can-
yon this siliceous crest gradually becomes less prominent, and
runs for some distance like a broken wall along the east side
of a high peak. This ridge is a noticeable topographic feature
of the locality. (PI. II, A, left side.)

Beginning with a thickness of 25 feet at the south end, the
thickness of the wall varies from 4 to 60 feet as far as Tijeras
Canyon. At the extreme north end of the outcrop the thickness
is about 400 feet. The effect of weathering has been to leave

_—_—,

1 Herrick, C. L., Geology of the San Pedro and the Albuquerque districts,
Bull. Univ. of N. Mex. Vol. I, 1899.
28 GEOLOGY OF

a more or less disjointed wall with nearly vertical sides rising
10 to 100 feet above the slope of the mountains. In some places
the rock pinches out to a thin wedge, and at intervals the con-
tinuity of the wall ceases abruptly. In other places the wall
splits into two or three parts separated by a distance of sev-
eral rods. The trend of the southern end is 30° east of north,
but the northern end is shifted eastward, out of line, by a
series of offsets due to faulting.

The rock in some places resembles a fine-grained quartzite,
having a streaked appearance, as of bedding planes, and a
purplish color. Other phases are quite schistose. There are
gradations between the two phases, and from schistose to
gneissic structure.

The banding is due to interlayered white or purplish quartz
with a dark purplish or black ferruginous quartz. The color
in some places is a uniform dark purplish brown, and in others
a very light tint or white. The ferruginous material is often
segregated into patches, so that the rock is somewhat regularly
spotted, as in leopardite. The bands vary in thickness and in
intensity of color, and frequently the rock is a pure, milky
quartz.

The structure usually is finely crystalline and massive, and
no sand grains are visible. It is probably of this rock that
Keyes’ writes when he says that such examination ‘‘demon-
strates conclusively that the rock has a clastic origin.’’ In the
schistose phases, quartzose layers an inch thick are common,
and on the surfaces of these sheets are seen lines and striations
indicating shearing. The more completely schistose portions
are much crumpled, and sericite is present in such an amount
as to allow easy separation of the layers. South of Tijeras Can-
yon a gray taleose schist 10 to 20 feet thick lies next to the
quartzose ridge, separating it from the brownish gneiss on
either side. Microscopic examination in thin sections shows a
very fine crystallinity, with no evidence of fragmental origin.
Even the more massive phases, which do not outwardly appear
schistose, under the microscope are found to be structurally
compressed and foliated. Between crossed nicols the granules
have a wavy extinction, probably due to molecular deforma-
tion.

This ridge may then be said to be a series of quartz schists,
embodying some phases of massive quartz, almost pure, resemb-

 

1 Keyes, Charles R., Geological setting of N. Mex., Jour. Geol., Vol. 28, 1920
THE SANDIA MOUNTAINS 29

ling quartzite. Whatever its origin may have been, it does
not now present the aspect of an ordinary bed of quartzite,
such, for instance, as occurs among the Algonkian rocks of the
Lake Superior region. Its position as related to other rocks;
the absence of certain evidences of clastic structure; the fre-
quent pinching out of the ledge; the decidedly schistose struct-
ure intervening between quartz layers, and the presence of
shear planes between these layers; the plication of pure quartz
layers running parallel with the general direction of schistosity
of the series; the absence of any indication of bedding planes—
these are some of the peculiar features presented in this
““quartzite’’ ridge.

The formation ends rather abruptly about 1 mile south of
Tijeras Canyon, but it reappears farther south, in Coyote Can-
yon. There several disconnected outcrops occur, which are
probably the result of faulting. The structures of these out-
crops and their associations are similar to those of the rocks
just referred to in the Tijeras Canyon locality. The dip of
schistsity, however, is southeast instead of northwest.

STRUCTURE
General Features.

The main geologic structure represented in the area is a
block mountain dipping steeply to the east, consisting of several
hundred feet of a sediments supported on a mass of igneous and
metamorphic rocks. (Pl. I and Fig. 1). The north and south
trend of this uplift is directed by a fault having an upthrow of
4,000 to 5,000 feet. The general eastward tilting of the block
is disturbed by many transverse faults whose downthrow is
to the south, Tijeras Canyon being directed by one of the larg-

LA LUZ VEIN
SANOIA MTS.
/g000 Et,

    
     
   
  

 

    
 

Ny VaLc ances
FAULT (A)

Aro Puerto
FAULT
Rio Grande

ce—y
Ss

 
   

pT Tce
2

=a

 
   

 

Fig. 1.—Ideal structure-section and profile from the Puerco valley east to the
Sandia Mountains. Length of section about 30 miles. (After Jones.)
30 GEOLOGY OF

est of these. Many subordinate uplifts occur on the general

eastward slope of the major block, contributing to the great

irregularity of surface in that portion of the area. There is no

place within the area where the sediments still maintain a

hortizontal position. Folds are infrequent and unimportant.
Faults.

The great fault zone extends along the western front of the
Sandias approximately parallel with the mountain crest. The
line of the fault is indicated by the precipitous wall of granite
and sedimentary rock that is plainly seen from the west. The
fault is normal, and the dip is steeply to the west. The amount
of vertical displacement is shown by the relative positions of
the rim rock and a mass of limestone lying at the base of the
mountains on the west side, between Embudo and Tijeras can-
yons. This small isolated area corresponds in character to lime-
stones found at the top of the Sandia ridge. It is easy to sup-
pose that the two areas of rocks were once on the same level.
Although no other exposure of this limestone appears on the west
side of the mountains, it is probable that the corresponding for-
mation does exist below the mesa deposits all along the western
front. It does appear at the surface over a wide area south of
the mouth of Coyote Canyon, outside the present area. The
variation in altitude between the western base of the Sandias
where the limestone occurs and the rim rock is at least 4,000
feet. In other words, the throw of the fault is that amout.
Six miles-farther north the throw is 1,000 feet greater than
this. Jones? believes the total vertical displacement is near
8,000 feet. (See, also, Fig. I.)

This fault does not occur as a single plane of fracture, but
the movement was distributed throughout a zone, or belt, a
quarter of a mile or so in width, forming a series of faults.
Single fault scarps 1,000 to 1,500 feet high occur between Pino
Canyon and the north peak of the mountains. The compound
nature of this fault system is manifested in a series of high
needle-peaks of granite, which fringes the mountain ridge
near its summit.

The northward extension of this fault is seen nearly to Pla-
citas. The southern end is not easily followed beyond Tijeras
Canyon, or even not quite so far as that. It is presumable that
the uplift of the Manzano Mountains represents a structure in
general similar to that of the Sandia Mountains.

 

1 Jones, Fayette A., personal communication.
Bulletin 108, Plate IV.

 

 

 

 

 

A—Rim rock and cliffs near Sandia Peak, rising 600 feet above
the granite.

 

 

 

 

 

B—Sandia Peak and fault scarp, from the mouth of Jaral Canyon.
32 GEOLOGY OF

A fault occurs in the northeastern part of the area with a
strike nearly due north and south. For convenience of refer-
ence this called ‘‘Huertas Fault’’. The downthrow is to the
west, and the amount of displacement is nearly 1,000 feet. The
steep escarpment of this fault forms the uplift called Monte-
zuma Mountain. Passing south from the vicinity of Tecolote
village, this fault extends to the vicinity of Palomas Peak, form-
ing the course of Canyon de las Huertas.

Along the crest of the Sandias are frequent offsets which
give it a very irregular outline, both horizontally and vertically.
These offsets mark the location of transverse faults, which ex-
tend far down the east slope of the mountain and are the de-
termining factors in the formaticn of canyons. The throw of
these faults varies from 100 feet to several hundred feet. The
downthrow is usually to the south. One of the most prominent
of these transverse faults forms the south gable of the Sandia
roof, cutting across the end of the quartzose ridge just as it.
passes beneath the eastward-sloping sediments. Tyaces of
this fault, or of its associated displacements, are noticeable at
the heads of several canyons reaching up northwestward, be-
tween Hodgotite Canyon and the lower steel bridge.

The number of local displacements appearing on the east
slope of the mountains is so great that it would be next to im-
possible to locate all of them, if that were desirable. This
broken condition of the surface rocks also renders very difficult
any attempt at precise mapping of formations. Palomas Peak,
the high ridge above Tejano Canyon Ranger Station, the ridge
just southeast of La Madera, and others, equally definite,—all
are accompaniments of fracture and upthrust. Sections of
strata form steep escarpments, and in nearly every instance
the granite basement is exposed.

It has been pointed out by previous writers that a fault passes
across the mountains at Tijeras Canyon, dividing the Manzano
range from the Sandias. Evidences of such a fault are not
certainly apparent. The escarpment of the mountains south of
Tijeras Canyon may be the result of faulting or of a rising mass
of intrusive and metamorphic rocks. There may be the possi-
bility of a fault movement having produced the peculiar struc-
ture seen in the quartzose ridge crossing the canyon, as de-
scribed above.

Relation of Structure to Topography

The topographic features are essentially dependent on the
THE SANDIA MOUNTAINS 33

structure of the underlying rocks. For the most part, the area
is one of degradation, and this erosive process is taking place
on rocks that are variable in composition ag well as complicated
in arrangement. Only in some of the larger valleys are there
sediments that lie relatively undisturbed and which are being
modified by recent erosion.

It is probable that every canyon on the eastern slope of the
Sandias was originally directed by fault lines. As elevation
of the several blocks went slowly on, erosion continued to lower
the intervening canyons, but it has not kept pace with the uplift.
A noticeable feature of these fault valleys is their straightness.
The valley of Huertas Creek follows almost due north for 6
miles of its upper course. It is manifestly along a fault line
whose upthrow side is recognized as Palomas Peak, Montezuma
Mountain, ete. Farther south, the Arroyo Canyoncito cuts its
way between upturned blocks of sandstones, to Tijeras Canyon.

Tijeras Canyon bears evidence of being an ‘‘antecedent’’
valley. Erosion has evidently sawed this channel through the
mountain range during its slow uplift. Approaching the moun-
tains from the east, the canyon cuts through a depression in the
roof of the range, almost at right angles to the strike of the sedi-
ments. Once within the area of crystalline rocks, the course of
erosion nearly parallels the strike of gschistosity for about 2
miles, in a general way following the line of contact between
the green schists and the purple gneiss. About 1144 miles
below the lower steel bridge the channel makes a sharp turn
to the right and cuts across the quartzose ridge. At this
point an arroyo enters from the southwest. It, also, follows the
line of the green schists and the purple gneiss, and may indicate
the former course of the Tijeras Canyon drainage.

After crossing the quartzose ridge (Pl. II, A), the course of
the canyon is nearly due west till it emerges from the moun-
tains. The canyon widens out in the vicinity of Carnuel and
contains a considerable acreage of alluvial deposits, which con-
stitute the farm lands of that community. There is no indica-
tion of the canyon following a fault in this part of its course
It evidently occupies a position where the granite mass was
originally lower than at other places.

On the west side of the range the drainage lines are not so
manifestly influenced by structure. However, it is possible
that here, too, faults may have been a directing cause. The
erosion has been more extensive than on the east side and a
B34 GEOLOGY OF

much longer time must have been required for the work. The
canyons are larger and their courses are more irregular. Bear
Canyon alone embraces a drainage area of 7 square miles.
Pino Canyon is about equally as large. The topography seems
to be the result of differential erosion in granites that differed
in resisting power. The mouths of the canyons are frequently
the narrowest part in their courses.

GEOLOGIC HISTORY

The chronological record of the area may be interpreted
somewhat as follows: Islands of igneous and metamorphic
rocks in the midst of the Paleozoic seas indicated the position
of the future Sandia Mountains. It is probable the area ex-
posed above the sea was much greater than that of the present
Sandias. <A large portion of the State of New Mexico was
apparently out of water previous to the time of the laying down
of the Carboniferous sediments. Formations of Paleozoic ages
earlier than the Carboniferous do not appear at the surface in
northern New Mexico, and it is not evident that such have ever
been reached by drill holes in that region. In the southern
portion of the State, however, strata of early Paleozoic age
appear at the surface. If these earlier sediments ever covered
this area they were worn away ages before Carboniferous time.
The Carboniferous sediments were laid down on a much-eroded
surface and by an encroaching sea. It is certain that the
amount of weathering and erosion of the erystalline area was
very much greater in amount previous to the deposition of the
Carboniferous sediments than it has been since the uplift of
those sediments to their present height. The difference in
degree of disintegration seen on surfaces within the fault zone
and those of the granite mass outside of that zone suggests a
longer period of weathering for the latter. Moreover, the
weathering of the limestones and sandstones of the roof of the
mountains is unquestionably less than has taken place on the
more resistant rocks making up the core of the uplift.

Over these ancient and eroded islands the Carboniferous seas
gradually encroached. Upon the wavebeaten shore the debris
of the crystalline rocks was assorted and more or less water-
worn. Boulders of the quartzose ridge lying across the present
Tijeras Canyon contributed largely to the deposits in that local-
ity. The white quartz from lenses in the schists at the base of
Montezuma Mountain now forms the most abundant material of
THE SANDIA MOUNTAINS 35

the overlying conglomerates there. And so, in other places,
evidence of the inter-relationship of the two formations is thus
shown. In some places, however, the conglomerate is absent
above the crystalline rocks, perhaps indicating a prolonged
period of quiescence, when the fragmental material would be
more completely reduced by the waves.

The settling of the land mass continued possibly until the
sea covered it completely. Depos:tion of fragmental material
—sand and gravel—became less. The waters, swarming with
life, now laid down thick beds of limestone. Frequent oscilla-
tions again and again brought a change in the type of sedimen-
tation so that sandstones, shales, and limestones intervene. A
glance at the section given for the Montezuma Mountains
shows the possible variability in kind and amount of material
deposited.

These slow oscillatory movements continued until several
hundred (700 or 800) feet of sediments were deposited. A more
rapid and more profound movement was now inaugurated,
which resulted in the permanent uplift of the Sandia range.
The elevation was not to the present height—probably not to
more than half that height, but it was sufficient to expose a
considerable area of the Carboniferous sediments to erosion.

This uplift accompanied and was due to a dislocation ex-
tending practically the whole length of the range north and
south. This was the beginning of the fault zone described
above. During this differential movement, the highest part
of the ancient mountain was being lowered bodily, while the
sedimentary area east of it was reaching a height equal to it
or even above.

After a period of erosion, in which the surface was greatly
modified, the area again was partly depressed beneath the sea.
The sediments that were now deposited rested unconformably
upon all the previous formations, filling the depressions and
eroded valleys: and leaving exposed the higher ridges. During
this time of sedimentation great areas of the sea were isolated
by land barriers, so that communication with the main body of
the ocean was infrequent. Conditions were favorable for the
deposition of minerals in solution, and thick beds of gypsum
were formed. Red sandstones and shales were accumulated to
great thicknesses. This series, sometimes referred to as the
‘‘Red Beds,’’ is now found in many parts of the State. <A por-
tion of the series is assigned by Lee to the Manzano formation,
36 GEOLOGY OF

or the upper part of the Pennsylvanian. In the vicinity of the
Sandias this red formation extends up the valley of Huertas
Creek and some distance into the angle formed by the upturned
limestones half a mile southwest of Tijeras. It also occupies
higher positions along the eastern slope of the Sandias. The
unconformable contact of the red formation with that below
is observable a short distance south of the prospect holes at the
west base of Montezuma Mountain.

Following the deposition of the beds, extensive uplift and
erosion occurred. Practically the whole area of the Sandias
was out of water from this time formard. An intervening for-
mation—the San Andreas limestone—between the red beds and
the Cretaceous deposits occurs farther south but it has not been
observed in this area. The next succeeding deposit is a series
of variegated sandstones and shales classed by Lee? as Mor-
rison beds. Above these are coal-bearing sandstones and shales
of the Upper Cretaceous.

While more or less oscillation occurred during the deposition
of Cretaceous sediments, the most extensive and profound dis-
location took place after these sediments were laid down. The
movements that then occurred caused a general upward tilting
of strata on the east and north of the Sandias, giving very steep
dips and local fractures. This uplift probably accompanied the
final great displacement along the major fault zone. It may
also have been that mineralization of the fracture zone was
earried on largely after this time. The origin of the lead-silver
ores, referred to below, may have been in magmatic solutions
ascending along these lines of fracture and being preciptated
by coming in contact with the limestone above. It is to be
supposed that the Pennsylvanian sediments had yet been only
moderately eroded from the underlying granite.

Since the general uplift at the close of the Cretaceous some
oscillation has occurred but no great movement has dislocated
the formations. The upturned sediments were rapidly eroded
and were re-deposited in the Tertiary lakes surrounding the
area. These deposits of gravel, sand, and silt, collectively
known as the ‘‘Santa Fe marl,’’ rest practically horizontal on
the upturned beds of the Cretaceous. While relatively soft,
these beds maintain sufficient coherency to be deeply cut by
erosion, forming a very rough topography.

1 Lee, W. T., The Tijeras coal field, Bernalillo County, N. Mex., Bull. U. 8,
Geol. Survey No, 471, 1912.
THE SANDIA MOUNTAINS 37

The Tertiary sediments to the north of the area are usually
covered with coarse gravel and boulders. These gravels now
reach to and cover the tops of elevations like Lomas Altas, 200
feet above the general level of the mesa, indicating that sub-
mergence to that level must have taken place at some time later
than the Tertiary period.

Again the area was elevated. This time the whole Western
Interior was affected, and erosion began rapidly to lower the
surface of deposits old and new.

After Tertiary sedimentation was well advanced, these sedi-
ments in many parts of the West were buried beneath lava
flows. Thus protected, these sedimerits remained uneroded
while adjacent areas were partly or wholly lowered to a new
level of erosion. In the area under discussion the only post-
Cretaceous invasion of igneous material is the basaltic dike,
already described, near Placitas. This dike cut through the
soft Cretaceous sandstones and shales after their main uplift
and dislocation. It may have been connected with disturb-
ances which elevated the Ortiz Mountains, from which numer-
ous similar dikes radiate.

MINERAL RESOURCES

COAL

Some coal beds occur in the Cretaceous rocks which border
the area on the north and east. These beds have been exploited
to some extent, but with no commercial production. The near-
est deposits of known importance lie a few miles to the north-
east in what is called the Hagen coal field.

The Tijeras coal field, which was prospected some years ago,
lies to the east of the main area of the Sandias, from the vicin-
ity of San Antonio northeastward about 4 miles. The condi-
tions in this field are described by Lee’. The coal-bearing rocks
are said to belong to the Mesaverde formation. The coal beds
are much fractured and distorted and do not maintain a uni-
form thickness for any great distance. In general, the beds
average less than a foot in thickness in the southern part of
the field, but are some thicker in the northern part. In 1921
the prospects had been practically abandoned.

Outcrops of coal near Placitas have been exploited but with
no permanent results. A mine was opened about 1881, and

 

1 Lee, W. T., The Tijeras coal field, Bernalillo County, N. Mex.: Bull. U. S.
Geol, Survey No. 471h, 1912,
38 GEOLOGY OF

from 2,000 to 3,000 tons of coal were removed during several
years following. At present, work is abandoned and the tun-
nels are caved in.

The coal lies in a shale member between two series of light-
colored standstones. The inclination of the strata is 30° to 40°
to the northeast. At a depth of 250 feet the coal is about 4
feet thick, with a shale layer 3 inches thick in the middle of
the bed.

This prospect is under the management of Mr. 8S. Seligman,
Bernalillo, New Mexico.

BUILDING STONES.

While granite, sandstone, and limestone occur in abundance,
it is not likely that the area will be called upon to produce
building stone, for some years to come. Access to these deposits
would not be difficult, if a demand should arise for the product.
The present highway from the mountains to Albuquerque could
be utilized for haulage to the railroad at Albuquerque, 10 to 20
miles,

Granite

The common coarse granite, or porphyry, exposed on the
west slope of the Sandias has been tried by the Fletcher Marble
Works at Albuquerque and has been found unsuitable for
monuments. It cannot be cut to a sharp corner‘on account of
the high content of mica and the consequent lack of cohesive-
ness of the rock. Also, the lettering does not show a good con-
trast with a polished surface. As a building stone, this granite
would be suitable, but there is no market for it.

Limestone

The principal use of the limestone has been for burning into
lime. This industry is not now important, but numerous aband-
oned limekilns indicate its former development. Even yet, an
occasional load of lime from Tijeras finds its way into market
at Albuquerque.

As a building stone, this limestone has had some local use,
and in a few instances it has been cut for monuments. For the
latter purpose it is not desirable, either as to beauty or dur-
ability.

Sandstone

Some very good sandstone is found in the Cretaceous forma-
tions adjacent to the Sandia Mountains. Near San Antonio a
quarry has been opened up and the stone has been used locally

 
THE SANDIA MOUNTAINS 39

to some extent. This stone is hard and almost white. It is
considerably jointed, however, which may be of such an extent
as to prevent quarrying in very large blocks, Among the many
occurrences of sandstone other localities might be found where
the stone would be of good quality, not badly jointed, and
suitable for all the purposes to which such a stone may be put.
GYPSUM

The upper red beds of the Manzano formations are character-
istically gypsiferous. The outcrops of such deposits within this
area, while not unusually remarkable, are worth considera-
tion. The principal locality is probably the one on the road to
San Antonito, about two and a half miles north of San An-
tonio. Here there is an exposure of gypsum 50 feet thick, ex-
tending for several rods just above and to the east of the ar-
royo. No use has been made of this deposit other than for local
purposes.

CLAY

About 1 mile south of San Antonito a bed of fire clay is re-
ported. This deposit was not examined by the writer. The
bed is said to be 3 feet thick. An analysis of the clay was made
some years ago, which shows it to be a good grade of refractory

clay. The analysis was made by F. C. Lincoln, New Mexico
School of Mines.

Analysis of fire clay from deposit 1 mile south of
San Antonio, New Mexicol

Fercent.

WUC 46S 55 e eS ESE S SOP PE eR BERGE RR 65.54
ACPUPTIR TNA. “YS Roc Sete ct ore Aad dou SMa oder atancs ahaa ash or aadan eras reat 25.76
TTI Cia. ester cia se sae a oie one eta a fe eee Ga eee trace
Ma@ePneSIO. to 3:00. Sse wemtie won Se ee eee eon eee a trace
Water 2c teaceeee Leh to ahoaay Bi cnante EA Ghat at a cisp a Nae RUE EE yank heed THEE TE eS 6.70
Oreamic: WATER 5 owes Me welecae sade Gee e Tes tena se jeeceate aria leMeiceriatlaaa tee 3 1.36
Undetermined (alkalies, etc.) ....... 0... ee eee eee eee 64

100.00

GRAPHITE

A deposite of graphite occurs on the east side of the Sandias,
near Whitcomb Springs. It is located about 30 rods west of the
spring, on the north side of the same canyon. The prospect
was opened up about 20 years ago. It is now owned by Mr.
Pitt Ross of Albuquerque. A small amount of development
work has been done.

The deposit oceurs in a much-folded and contorted formation
of the Pennsylvanian system. It is intimately associated with a

 

1 New Mexico mines and minerals, p. 252, 1904.
40 GEOLOGY OF

crystalline limestone and a coarse sandstone, or conglomerate.
The graphite varies in thickness from 1 to 3 feet. The mineral
is a rather impure grade of the amorphous variety. -

It is interesting to note that this deposit is situated prac-
tically in line with the quartzite ridge, that crosses Tijeras
Canyon and passes beneath the sedimentary series about half a
mile to the southwest. The deposit may be genetically related
to the disturbance which produced that quartzitic core.

ORE DEPOSITS

The Sandia Mountains are not known commercially as a
mining district, since but little production has yet occurred.
Prospecting has been carried on for many years, and the rug-
ged slopes are filled with many test-pits. There is, however, a
belt of metalliferous deposits associated with the system of
faults that traverses the mountains north and south. Farther
south, the extension of this fracture system holds deposits that
have attained some importance as future possibilities for pro-
duction.

La Luz ‘‘Mine’’

The best known and the most thoroughly developed pros-
pect is the La Luz group of claims. This group is located just
below the rim rock on the west slope of the Sandias, about 18
miles northeast of Albuquerque and 10 miles east of Alameda.
A good road leads to the foot of the mountain, about 3 miles
from the prospect. The rest of the way is dificultly accessible,
but is accomplished by a good mountain trail.

This claim was discovered in 1887 by a Mexican named Juan

 

 

A-8 =/350Ft
Fig. 2, Sketch map and section of La Luz mine. (After Jones.)
THE SANDIA MOUNTAINS 41

Nieto. Its location was then lost, but was re-discovered in 1907.
The property was purchased by Mr. B. Ruppe and others. In
1909, the present company, La Luz Mining, Smelting and
Development Co., was formed. Up to the present time (1921)
considerable development work has been accomplished. About
600 feet of tunneling has been done, but no ore bodies of com-
mercial size have been exposed.

The main ore body lies in a fissure vein 2 to 4 feet thick,
which parallels the mountain crest at the base of the sediment-
ary formations. (Fig. 2.) The fissure belongs to the general
system of faulting that extends along the western front of the
Sandias. A minor fissure extends nearly at right angles to the
main fault. Some ore also occurs at the contact of the sedi-
mentary beds with the granite.

The ore consists principally of lead and silver, but there are
small values of copper and gold. The gangue contains an
abundance of fluor spar. The prospects seem favorable to find-
ing deposits of commercial importance at greater depths.

Kleinwort Prospect

On the north slope of the mountains about 2 miles southwest
of Placitas is the San Jose group of claims, belonging to Emil
Kleinwort of Albuquerque. This prospect is about 6,000 feet
elevation. Another group—the Buckeye—is located about
1,500 feet higher and 14% miles farther southwest. Consid-
erable development work has been done on the San Jose group.
Two shafts have been sunk on the fissure vein and a tunnel is
approaching this vein from the northwest.

The mineralization occurs in a fissure vein striking south-
west, in general paralleling the main line of displacement that
constitutes the northern portion of the Sandia uplift. Good
values of copper, with some lead and silver, appear in the

oxidized zone, and it is hoped that a zone of enrichment will be
found below.

Montezuma Prospect
Prospecting has been carried on for a number of years at the
base of Montezuma Mountain. The location is about a mile
east of Placitas and on the west side of the mountain. Several
shafts have been sunk, to depths of about 100 feet.

It was impossible to secure data on the success of the develop-

ment of this prospect. A deposit of lead and copper ore occurs
along the contact of limestone beds and schists. The deposit
42 GEOLOGY OF

seems also to be present in a fissure vein cutting the schists.
Fluorite occurs abundantly in the gangue. :

Conclusions on Ore Deposits

While the Sandia Mountains have not been considered favor-
able as productive of mineral in commercial quantities, much
remains to be determined in this respect. To those who have
looked into the conditions the most thoroughly, the prspect
seems very favorable for a possible development of productivity
on a commercial scale. In addition to the metallic ores that
seem relatively abundant, large quantities of fluor spar ore
are in sight. The full possibilities of these deposits urgently
await the application of capital and the most thorough investi-
gation.

WATER RESOURCES

Streams

There are no streams in the area that can be called perman-
ent for more than a few miles. The sudden precipitation and
small amount of the rainfall of the general region and the por-
osity of the soil result in gravel-choked arroyos, often flooded
for an hour, and a more constant underground flow. Any de-
gree of permanency that may be attained by the streams is due
to the presence of springs. The distance to which these streams
extend varies according to the changing conditions of tempera-
ture and rainfall throughout the year. In general, running
water is more abundant on the east slope of the Sandias than
on the west. The jointed and cavernous condition of the rocks
and the more gentle slope contribute to the retention of a larger
per cent of the rainfall. Forestation no doubt aids in this, and
the actual amount of yearly precipitation may be greater on
the east side of the mountains. These occurrences of running
water usually may be more appropriately referred to as the
overflow from springs.

Springs

Mountain springs are abundant and well-distributed, and are
utilized to a great extent in the general economic activities of
the region. They are more numerous on the east side of the
mountains than on the west. Almost every canyon on the east
slope cuts into the water-bearing rocks and is thus supplied.

The water of the springs on the east is heavily charged with
lime carbonate. This material is taken into solution by the
rainwater as its passes down through erevices in the limestone
THE SANDIA MOUNTAINS 43

strata. Where the water emerges, some of the material in
solution is precipitated, forming encrustations and masses,
called calcareous tufa. These deposits in time accumulate to
such an extent as to become very noticeable. Well known ac-
cumulations are those of Lorenzo Falls and Whitcomb Springs.
No such deposits are observable around the springs on the west
side of the mountain, since limestone beds are absent on that
side.

The presence of these springs is indispensible to the herding
industry in the mountains and on adjacent territory, as well as
to the maintenance of permanent settlements in the valleys on
the east. The water is often conducted far from its source by
means of ditches or through iron pipes scarcely buried beneath
the surface.

In addition to their furnishing an adequate supply of drink-
ing water for man and beast, these springs have considerable
value for irrigation purposes. A number of them are used in
this way, although for the most part, crops in the region east
of the Sandias are grown without irrigation. The narrow strip
of tillable land bordering Tijeras Canyon is supplied largely
by water that comes from Whitcomb Springs. A portion of the
water of this canyon is conducted across the mesa to a ranch
several miles beyond the mouth of the canyon. The underflow
in the arroyo leading from the canyon is made available for the
needs of a number of ranches located in the bottom of the
arroyo.

The stream that flows from springs near Ellis Ranch is strong
enough to maintain its above-ground course at least 5 miles.
In that distance the descent is about 2,000 feet. The flow
eradually diminishes as the stream comes out on the gentler
slope 2 miles south of Placitas, and it is finally completely
absorbed by thick deposits of coarse gravel and boulders. In
the growing season this stream is diverted through a ditch to
the fields in the lower part of Canyon de las Huertas. The
orchards and gardens of the village of Placitas are supplied
in a similar way from another spring, flowing possibly 40 gal-
lons per minute.

Water-Power

At present no utilization is being made of the energy of the
mountain streams. For the most part, the amount of flow is
not worth considering as a motive power. It is possible that
such a spring as that emerging at’ Whitemb Springs might be
44 GEOLOGY OF

so used, for local purposes. The flow is approximately 40 gal-
lons per minute and the fall is about 500 feet in the first half
mile.

The stream most likely to be of practical use as a source of
power is Huertas Creek, coming down from Ellis Ranch. The
flow for several miles is approximately 100 gallons per minute.
The fall for 2 miles or more is 750 feet to the mile. The utiliza-
tion of the water for power would, of course, not impair its
present use in irrigation.
INDEX

 

Abo formation, .

 

Accessibility .........0...c cc eee
Albuquerque, humidity of........ 9
B

Baker, OC. L., cited...........--.
Basalt .s.¢a 80.06 04% real a
Base level, ancient...
Bear Canyon ........----+-
Board of Regents mentioned..... 5
Boese, Emil, cited.........-+--+5 16
Building stones.........eesee eee 38
c
Canyoncito Arroyo ......+eeeeee 33
Cedro Ranger Station........-. 8, 9
Chupadera formation.........+.-+ 17
Cienega Canyon, mention of...... 7
Clark, Dr. John D., mentioned.... 5
Clay 39
Climate 8
Coal 3°

 

Coyote Canyon referred to.......- 30

  

 

 

 

Cretaceous rockS ....---++eeeree 2)
D
Darton, ee fines F iadenehe ta
Dike near Placetas... oe cance
Dikes, granite....-...65e eee ree 28, 25
E
Ellis Ranch, mention of-........- qT
springs near ....-ee seer reese 43
Embudo Canyon, view near......- 12
Estancia Valley......----+++eee? 7
F
Falls, Lorenzo, mention of...... 7,43
Faults, description of........-- 30, 32
figure showing ...--.---- . 29
Fluorite, occurence of......-.- 42
Forestation ......+--eee+e seers 7
Galisteo Creek .....--6-+--+-+-> 7
Girty, G. H., cited 17
Glasebrook, ‘‘Larry,’’ mentioned.. t
Gneiss 1... eee eee ett ae
Goat raising ...---+-- seer e ree
Granite ...-: eee eters 21, 22, 38
Graphite ...--- 2-0 eee er etree 39
Gypsum... - ee eect eee 39
H
Herrick, C. L., cited. .6, 15, 16, 21, 27
Hill, Pres. David S., mentioned... 5
Hodgotite Canyon .--.+-++++e+- 7,32
Huertas, Canyon de las........- 15, 32

sence es 38, 43, 44
32

 

Igneous rocks ..- sees re settee 21
Indianapolis, Ind., humidity of... 9
Tndustfies ccc es ce ee eee ee ee tee 10

J
Jones, Dr. Fayette A., mentioned. .5, 30

K
Keyes, Charles R., cited.......... 28
Kleinwort, Emil, prospect of...... 41
L
La Luz ‘‘mine’’ .....--++eeeeee 40

La Luz Mining, Smelting and

velopment Co. ......
La Madera, rocks near.......... 26
Lee, W. T.. cited.....---+-- 16, 17, 21

De-
oe. AL

Page

Lead-silver ore ..........000005 “a

Limestone sa sac8 eax dette age 38
M

Madera limestone .............. 17

Manzano group................ 16, 17
Manzano Mountains, structure of.. 30
Manzano National Forest

 
 
  

 

Mesa deposits .............
Metamorphic rocks
Montezuma Mountain.....
Montezuma prospect ............
National Forest, Manzano, mention

OL. sdsin ey aihe Sotdcee A Snel ole D ie Y

oO

Ortiz Moutains ............... 24, 37
Palomas Peak ................ 20, 23
Pennsylvanian system........... 15,17
Permian system..............00- 17
Pino Canyon, Sawceieraus by eee ak 34
Placitas, rocks underlying........ 21

coal near ......... aicine le Aare tors 37

Quartzose ridge, description
Of 4 BSS Oe Shee 27, 29, 32
VIGW Of. s fot Ge anoles te-Miucl did ee iononiead 11
B
“Red: Beds!” 2s 2s04 aus tacee aan 35
Rim rock, view of.............. 31
Rincon Mountain, description of.. 12

TOCKS: OF: tid seetiasaiaeiien pace shies ge ay 24, 26
Ross, Pitt, prospect of.......... 39
Rotary Club, mention of......... 7
Ruppe, B., prospect of.......-.-. 41

Ss

San Andres limestone.......... 17, 86
San Antonio, rocks near........ 21, 39
San Antonito, rocks near......... 21
Sandia formation ..............- 17
Sandia Mountains, views of...... 13
Sandia Peak, view of........... 20
Sandstone: esi 2 eka vane oe5 ase 38
San Pedro Mountain ............ 6
“Santa Fe Marl’’............-- 36
Schists, description of . 24
Springs’ | asa cee cea wes. 42
Streams sicgeda deeds othe b emaiey 42
Structure, description of ........ 29
Structure-section, Rio Puerco-

SANGIAS: a5 cn A ee Pe a lle 29
Tejano Canyon, mention of....... 7
Tight, W. G., cited............. 5, 26
Tijeras Canyon, description of.... 33

WACOM: AM = i edd sth oseneriaiecsra: Roe ety 11
Tertiary sediments ............. 37
Topography ..........e eee eae 12

U
U. S. Forest Service, cited...... 5, 10
U. S. Geological Survey, cited.... 5,6
Ww
Watery TESONREES 4 cace yea yeaa es 49
Weather, record of............. 9

Well Country Camp, mention of.. 9

Whitcomb Springs, utility of....7, 43
White, David, cited.......-.0... "47
Y
Yeso formation ................ 17
<>

“WN °N ‘aNDYaNoNs Iv
MBLNIUd ‘SHHONH “SOHL
University of New Mexico.

XN

Maqdalenagroup

(lark gray, sic ous limestones, and sandstones)

Penns ylvanie

UNCONFORMITY
IGNEOUS ROCKS

Basalt
(dike, dark gray to black)

QUATERNARY

ey 7
7 Ii~Tt~
NIle NI

Granite
(coarse, porphyritic; phenocrysts of
pink feldspar)

METAMORPHIC ROCKS

Fo

h : hibes k t #8
greens "a or purpusn rocks, cu
onite pines: gudrix veins, etc.,’contortéd)

*
Gneiss
(brownish, contorted rocks; often senistose)

PRE-CAMBRIAN

J n ™ °
IN Coe, NX Cy?

eas
nS pi

; Quartzose ridges ‘
(white quartz, quartz SChiSté or quartzite)

GEOLOGIC MAP

OF 'THE

BR irNE A N. At
INDIA If 1 IN ] AINS Scale a
Feet, 5000

NEW MEXICO a
By R-WEllis

 

MANZANO GROUP
MESA DEPOSITS

 
 

Go ek

RS

 

é
K
‘
p
a
S/7
a2
ee
9
2
>.
°

oS
sy
LY

SEDIMENTARY ROCKS

No pattern;
west of
mountains

Mesa deposits

(sand,gravel and bouldgrd
UNCONFORMITY
[7

XX <>
SES

Mesa Verde and Mancos formations

  
    

aS

      

(“ght-colered. sandstones and gray
Shales; coal-bearing)

CRETACEOUS QUATERNAR

—_—_, —_—.

Manzano group

Ys
l

(Ted shales and sandstones Red Beads")
UNCONFORNITY

Pacdalenaarcaiinm |

CARBONIFEROUS

vanian

_ Copyrighted by the State University of New Mexico
Plate I.

Bulletin 108.

  
  

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m
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m
=
oO

   
   
  
 

}

eae ae ff ff
gc allegas. Ranch tne df ph L Paes fig OOS

: tT ;
a : 2 a ‘ Prevailing dip of beds
a a ea ae “ 7

  

x

      
 
  
 
 

AS

 

Strike and dip

40°

a
o
be 7
x
FG
5
3
A
A
uv

of schistosity

lf

"Rim Rock"
(highest part of Sundia ridge)

 
  
 
 

i be
ye OK Palornas Pk

Ellis Ail NO “y

 
       
  

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