Chapin, C. 8., and Cather, S. M., 1981, Eocene tecronics
and sedimentation in the Colorado Plateau-Rocky
Mountain area, ln Relations of tectonics to ore deposits
in the southern Cordillera, W R. Dickinson and W. D
Payne, eds.: Arizona Geological Society Digest, v. 14, p.
173-198
Dane, C. H., and Bachman, G. O., 1965, Geologic Map of
New Mexico: U.S. Geological Survey, 2 sheets, scale
l:500,000
EuBster, H. P., and Hardie, L. A., 1975. Sedimentation in
an ancjent playa-lake complex-the Wilkins Peak Member of the Green River Formation of Wyoming: Geological Society of America, Bull., v. 86, p. 3 l9-334
Eugster, H P., and Surdam, R. C., 1973, Depositional environment of the Green River Formation of Wyoming-a
preliminary report: Geological Society of America, Bull.,
v . 8 4 ,p . l , l l 5 - 1 , 1 2 0
Fisher, W L., Brown, L. F., Jr., Scott, A. J., and
McGowen, J. H., 1969, Delta systemsin the exploration
of oil and gas: University of Texas (Austin), Bureau of
Economic Geology, ResearchColloq.,2l2 p
F i s h e r ,W . L . , a n d B r o w n , L . F . , 1 9 7 2 , C l a s t i c d e p o s i t i o n a l
systems-a genetic approach to facies analysis: University of Texas (Austin), Bureau of Economic Geology,
2ll p.
Fitzsimmons, J. P., 1959, The structure and geomorphology of west-central New Mexico: New Mexico Geological
Society, Guidebook l0th field conference, p. I l2-l l6
Galloway, W . 8., 1977, Catahoula Formation of rhe Texas
coastal plain-origin, geochemical evolution, and characteristics of uranium deposits: University of Texas
(Austin), Bureau of Economic Geology, Rept. of InvestigationsNo. 87, 59 p
Gilbert, G. K., 1885, The topographic fearures of lake
shores: U.S. Geological Survey, Annual Rept., no 5, p.
69-t23
Grover, N. C., and Howard, C. S., 1938, The passageof
turbid water through Lake Mead: American Society of
Civil Engineers, Transactjons, v . lO3, p.720-732
Hantzschel, W., 1975, Treatise on invertebrate paleontology, Part W, Trace fossils and problematica: University of Kansas (Lawrence), 2nd ed., 269 p.
Hjulstrom, F , 1952, The geomorphology of the alluvial
outwash plains (sandurs) of Iceland, and the mechanics
of braided rivers: Washington, D.C., International
Ceographers Union, lTth Congress, Proc., p. 337-342
Johnson, B. D., 1978, Genetic stratigraphy and provenance
of the Baca Formation, New Mexico, and the Eagar Formation, Arizona: M.A. thesis, University of Texas
(Austin), I 50 p
Langbein, W. B., 1961, Salinity and hydrology of closed
lakes: U.S. Geological Survey, Prof. Paper 412, 50 p.
Massingill, G L., 1979, Geology of the Riley-Puertecito
area, southeastern margin of the Colorado Plateau,
Socorro County, New Mexico: D G.S. thesis, University
of Texas (El Paso), 301 p.; New Mexico Bureau of Mines
and Mineral Resources,Open-file Rept l0?,301 p.
McGowen, J. H., 1970, Gum Hollow fan delta, Nueces
Bay, Texas: University of Texas (Austin), Bureau of
Economic Geology, Rept. of Investigations No. 69, 9l p.
Mothersill, J. S., 1975, Lake Chad-geochemistry and sedimentary aspectsof a shallow polymictic lake: Journal of
Sedimentary Petrology, v. 45,p 295-309
Normark, W. R , and Dickson, F. H , 1976, Man-made
turbidity currents in Lake Superior: Sedimentology, v
23,p.815-831
P i e r c e , H A , D a m o n , P . E . , a n d S h a f i q u l l a h ,M . , 1 9 7 9 ,
An Oligocene(?) Colorado Plateau edge in Arizona: Tect o n o p h y s i c s v, . 6 1 , p . l - 2 4
Potter, S. C 1910, Geology of Baca Canyon, Socorro
County, New Mexico: M.S. thesis, University of
Arizona, 54 p.
Smith, N. D., 1975, Sedimentary environments and late
Quaternary history of a low-energy mountain delta:
Canadian Journal of Earth Sciences, v. 12, p 2,N42,013
Snyder, D. O., I 97 | , Stratigraphic analysis of the Baca Formation, west-central New Mexico: Ph.D. thesis, University of New Mexico, 158 p.
Surdam, R. C., and Wolfbauer, C. A., 1975, The Green
playa-lake complex: Geological
River Formation-a
Society of America, Bull., v. 86, p. 335-345
Theakstone, W. H., 1976, Glacial lake sedimentation,
Austerdalsisen, Norway: Sedimentology, v.23, p 671688
February1982
New Mexico Geologt
Palomas
volcanic
field,southern
NewMexico
andnorthern
Mexico
Chihuahuo,
0y
Thomas
J. Frantes
andJerryM Hoffer
Depattmen
t ol GeoIogical Sciences,
TheUniversity
of Texas(El Paso)
El Paso,Texas
Introduction
The Palomasvolcanicfield (late Cenozoic)
setsastridethe internationalborder in southcentralLuna County,New Mexico,and northern Chihuahua,Mexico,approximately80 mi
west of El Paso, Texas (fig. l). The field
coversapproximately380 mi'zand is bounded
on the eastand westby longitudes107'35' W.
and 107"55' W., respectively.
Lowman and Tiedemann(1968)namedthe
volcanicrocksthe Palomasvolcanicfield after
a brief reconnaissance
of the area.Balk (1962)
mappedseveraloutcropsof the volcanicrocks
north of the internationalborder.However.to
date, no publisheddata exist on the distribution and occurrence
of volcanicfeatureswithin the volcanicfield.
moresideswherelavaappearsto havebeenextruded.Fusiform, almond-shaped,
cylindrical
ribbon, and cow-dung bombs are locally
abundant around the base of many of the
cindercones.
A number of cinder conesdisplay a basal
section of pyroclasticmaterials capped by
denseflow rock. Theseconesare interpreted
as the result of lava welling up through a
cinder-spatter
coneand pondingin the central
vent. Subsequent
erosionhasremovedthe encircling pyroclasticmaterialswhile removing
very little of the more resistantdenseflow
rock (fig. 5). In addition, severalcindercones
havebeenmappedthat containconcentrically
orienteddikesat thetop of the cone.
Drxss-A numberof basalticdikesare exposedin the Palomasfield. The dikes are of
olivine basalt and are primarily associated
Volcanicfeatures
with cinder cones.The dikes dip nearly verRocksin the Palomasvolcanicfield consist tical, areseveralfeetin width, and average400
primarily of olivinebasaltand associated
dif- ft in length (figs. 6 and 7). Severalof the
ferentiatesof andesiteand trachyte.The field cinderconesare locatedat the intersectionof
is located on the westernflank of the Rio two or moredike trends.
Granderift and displaysa numberof differThe dikes display two different orientaenceswhen comparedto olivine basaltoccur- tions. One group are linear and strike in a
rencespreviouslyinvestigated
within therift in generallynorth direction.Thesedikesare l-15
southernNew Mexico. Thesedifferencesinft wide and extendfor distancesof up to a
clude: l) an older age comparedto the rift maximumof 2,000ft. Approximately8090
of
basalts,2) the occurrenceof more highly difthemappeddikesarelinear.The secondgroup
ferentiatedmembers,and 3) the occurrence
of occur as curving ring dikes near the top of
a numberof interestingvolcanicfeatures,inseveralof the cinder cones;thesedikes dip
cluding "pillow" basalt structures, basalt
dikes,and lava-capped
cindercones(fig. 2).
LavR nlows-Olivine-rich basaltflows are
the most dominantfeaturesin the field. They
are moderateto highly weatheredand havea
partial mantleof eoliansand.The flows range
in thicknessfrom I to 40 ft, but averageapproximately l0 ft. They range from highly
vesicularto extremelydense.
The olivine basalt displaystypical vertical
joints whereasthe more highly differentiated
membersof andesiteto trachytecomposition
are characterizedby well-developedclosely
spacedplatyjoints (fig. 3).
Locally abundantare xenolithsof feldspar,
quartz, peridotite,and orthopyroxene;these
rangein sizefrom 2 mm to 4 cm.
CINosncoNES-Over 30 cinderconeshave
been mappedin the volcanic field (Frantes,
1981,fig. 4). The cones,rangingfrom 100to
350ft in height,showsingleor multiplevents.
The conesare compositeand consistof interbeddedcinder, agglomerate,denselava, and
ro9"
toTo
lo5o
to3o
agglutinatedspatter.They have steepslopes FIGURE 1-INoEx MAp sHowrNc pALoMAs voland the rim is typicaly breachedon one or
CANICFIELD
almost vertically and partially encircle the vent
area.
CoNcsNrnlc BASALT sTRUCTURES-In a
roadcut approximately l6 mi south of Palomas along Mexico Highway 25 are exposed
oval to circular structures of dense basalt with
interbedded hydroclastic materials. The structures range from 5 to over 25 ft in diameter
and display concentric jointing patterns (fig.
8). They display an outer rim of very glassy
tially sank while squeezingsoft sedimentbetween and around what are now seen as
sphericalpillowlikestructures.
basalt grading inward to fine-grained dense
basalt.
The above structures, seen only in two
dimensions, represent pillow basalts or large
lava toes. The presenceof interbedded hydroclastic materials. which are stratified with
graded bedding present locally, indicates extrusion of basalt into a hydrous environment
(fig. 9). The basalt flows may have flowed into
a shallow lake where they broke up and par-
Compositionof basalts
The mineralogy and chemistry of the
Palomas volcanic rocks are summarizedin
table l. Basedupon their composition,three
major rock types are represented:olivine
F
basalt,andesite,andtrachYte.
Alluviuh-. Ool-_ !r/rr,dt de@sits o( tond,.ilt,a4d grdv€lrcoter. the ftol
olu,io/
g.oup.
Coal.tced
Qol
hilt and nountain
blson ptoin ut.c.n
bv
ldlgo d.cds cdt..ed
st.oh
al/utiun;
sffie yountrr
lansJ c6lotn.
aind b/Nn tahd
-T----l
rl E
z
lg
loorloorl
aod tPdilc.i l.$ thaa 50fl
llor3,tco.io,c/nde.
Bosoll-fb...Aosott
basdtt
lnick j tlot roct it hnso to fflabl.,
t.oy lo b/ack, o/iv/n.-.ich
cohtolns phanocrfsrs ol otivine,cJinoqv'
dilla..ntioles,
and int tn.dldta
p/ogioclas.;
b idinqtit
is cohnoh.
d olitin.
an.frt/n
roren,ond
F;T*;l
ll\l
Ihd-
T--' s l
|
I
dik6.
aosn
tu.|/
e.t.d
Gif o (? ) Conqlomerote@ngloma.otic sondtlonc,
ceglom.ole,
cenanted
and bcdded, wk/t
nudsloia, and sillslona, lolo/
UNCON FORMITY
I Trl
Flots,bl.ccios,ond
tulls ol /i|hl-qrdt
Rhyoliie ond lolile
brcsn lntol/la ood lotit€; tlicro.ts
P.oOdblv erc$ds 5OOll
ptl
doh/noDl /n no.lheotl
of o..d; Plrelatllct
I
to raddish
io south.m
UN CONFORMITY
lr.b
-l I
|
luonzonile,rhyolile,ond
lolile drkes
posilon to quortz honron/te
inlrut/on;
orlncioat di*es o.e 5hovn.
Ettudl
Xenol;lhs
CrelaceoB
ctosalv related/n age ondenonly
hasl dhes o.e gorphy//lic;
,eno//ths of Poteazolc
Hlshtt s)licillod ond silcolad
q,or12 nonzontlt.
tilhln
sedimantoly
rocht
ond
to l/ne groined, aeuiqlorubr
cotolad,nediun
Quorf r monzonife-Auil
quortz nonzonile;
esenlid//!
of o/i40'
porphyr/ltc
conqted
lo sl/ghl/t
c/dte, polosh lc/dsPor, ond tome ho.nbtende-
t:--l
t'l
r ---r-----l
lrolroil
o9s/onardtes,
dnd tufft of g/avish Nrp/c
,tacciot,
Andesite-To-F/o?r,
dnd ho/tbt.Ddedle
hol etceed LOOO0; on&sine
ondctite; tfrcrftst
henohte
najol conttilueDtsj pu.ptlsh colo. is duc lo finary di3seninol&
d. erl.ue/vc
conpa6/th,
etsanllo/ty
tha
somc
oidesitc
of
Ioi lntrusirc
ho.nb/ende Phenocrv.tt
contoinhq
aDdesllc i lfpico//!
Po.phytilrc
Oldet lol i e' A.ecc/os, ta lded lulls,
ldn lollle;rachs
ol g.ot lo fe/tovith
E
dDd 5 u bol dina I e Prp rv.' tic f /ott
ore c1nstdeldb/y oUeled; chtorile
UNCONFORMITY
Kul
I
Kc
I
I
lotsilifa.ou.,
liqht lo dork glov' thi,-to thh,
Upper limeslone-Sparca/y
thick;upPer 24oll
contoins ndulol
Nt.
lhon 3frtt
bed&d tnettoE;
in omount uped.d
che.l lhal lncle.e.
ond /inetlone - cherl conglonerde;
L/heslona
Limeslone conglomeroleoboul 45O/l thtct; Pcbb/es, cobtl.s, ond lhe fel bouldeft ore sutungutth tone ttognenk
/incslo,e
lat to tcll /ouDd.d aDd consitt of varidut
motrix is //nv' terl line lacod..e'
ol che.t,dalomitc,aodsdndttone]
is /igll qrdv' teng.oined quartt
ond chc.t sdadstoae; botat 35-4Oft
leDs6 ol re&ish o.koeE sondstone
sondstffir
tlcrlot, ctEstoninoted
and 3/llslone
I X-r
I
f''--]]l
no
I
I
J
in uPPe/ Porl.
[ro$ive
limeslone-6rd/,
cod rse /v c.vt to / / i na / i ne sloo e o ba u I J95 tl
lanses of
beds; nea. loP orc scottc.ed
thid;sona
chc.ty and sllicoaB
/imcslonc' Pe bble c oao/oncrolc
about 37511 ol chert cong/omc.dta'artoticto
Bosol closlic tocksqua.tzo.c .ondstone, Dola red siltttone, drd g/at ti/iceous liDectona
,"**",ail
[J
|
|
fP
I
Me
f;l |
siliceous
]
tacls-about
560lt
th/ck oad Probabtl of Drddle Pann
Pennsylvonion
linestonc
rac.ystd/rzd
kstititarcu.
AEe / a/nost conpt.te/y
sllvonian
thict .andstunc,
ond /antet ol sha/8,ondo @-l/
ercepl lat portioq
I
l
ond cherly lituis erpotedlD
mo.si@,uino/do/'
L/ghl-?/oy,
thich but onty the uPpe.mo.t
Escobroso LLmeslonetloDe;mole thon J6Oft
th6 rdDae,
g
n/ta
r"
u,u**"
I
Morc thor s25rt at chert @stomerote,
Hueco Formolion
tina.tone
crtttotrac
L@cato4e, oDd nots'ta
Polt
dnd ttncrtohet ' rcretol
dolodtes
Fusse'mon Dolom, e- ilorDtetnd
td?vuggy host:'e dotontt. it rvpLot oltheunit.
hund.cd teetthcr,
*
l
l
Crnder sPoiler con€
locoted. dotted where conceoled
*'--
"
rou"
where conceoled
Doshed where opproximolely locoted.dolt€d
A
tt
. l't7".
El /^e
9l t:
-l /c'
,r€
o
FE----l
I
|
o
2
|
2
3
3
4mi
4kh
EEE
E
Approximot6 M.oh O.clinolion
FIGURE 2-Cpo1ocrc
and Clark (1981).
uap on Peloves volcANrc FTELD;Tres Hermanas Mountains mapped by Balk (1962) and Sierra Boca Grande mapped by Robinson
New Mexico Ceology
February1982
i
]=
---'-conlacl
Doshed where opprorimolely
:
TABLE l-Cnnrrcel
coMposrrroN AND MINERALocy oF volcANrc RocKS, Palovns FrELD (l =
number of analyzed samples, * :
total Fe
reported as FerOr).
Chemical
Oxides
sio,
Tio,
Al,or
FerO'+
MnO
Mgo
CaO
Na:O
KrO
P,O'
Olivin€
Basalt (37')
Andesite (7')
Trachyte (8t)
52.63
1.66
15.25
9.93
0 .l 5
3.96
't.15
57.95
I -40
15.37
'7.03
45.26
2.38
14.57
1t.83
0 .l 6
10.59
9.09
2.93
l .l 6
0.54
4.58
1 1')
98.5I 9o
Mineralogy
Plagioclase
0.63
99.66V0
Olivine basalt
Clinopyroxene
Olivine +
Iddingsite
Biotite
Magnetite
Glass
0.r2
1.45
5.03
5.12
3.00
0.63
97.l0Vo
Andesile-Trachyte
JJ
60
(An'o)
(Anor)
ll
20
18
0
9
20
10090
4
8
9
8
10090
FIGURE 3-Cr-osnr-y spAcED pI-Ary JOINTING IN
BASALTFLow located approximately 16 mi south
of Palomas on Mexico Highway 25.
FIGURE 4-CrNnrn-sperrER coNES, lN
GROUND,
ATNORTHENDOFVOLCANIC
FIELD
BACK
FIGURE 5-CrNnEn-sperrER coNE (LowER sl-opEs
OF CINDER)
CAPPED BY DENSE LAVA FLOWS (CLIFFS):
TresHermanasMountainsin backeround.
February1982
New Mexico Geology
The olivine basaltsare fine-grained to glassy
and contain abundant olivine and pyroxene.
Chemically, they have low SiO', Na,O, and
KrO concentrations and high MgO concentrations. In the field, the basalts are typically
dark gray to black and dense.
The andesitesand trachytes are more coarse
grained and contain more plagioclasethan the
basalts. Chemically, they contain more SiOz,
Na'O, and KrO and less MgO, FezO:, and
CaO than the basalts. The andesites and
trachytes are generally light to brown in color
and display platy jointing.
FIGURE 6-Bnsnlr
DrKEourcRop. sourHwESToF
Basalt agesand origin
Field relationships show that the olivine
basalts are younger than the andesitesand trachytes (Frantes, 1981). Three occurrences of
olivine basalt have been dated (K-Ar) from
southern Luna County, New Mexico, giving
d a t e so f 2 . 9 6 + 0 . 0 7 ,3 . 9 1 + 0 . 1 8 ,a n d 5 . 1 7 +
0.ll m.y. (Hawley, 1981). The Palomas volcanic rocks are therefore at least Pliocene in
age.
The rocks of the Palomas field are clearly
differentiated, and it is suggestedthat the differentiation is becauseof fractionation in the
magma close to the earth's surface.
Solidification indexes (SI) of the Palomas
volcanic rocks were calculated (after Kuno
and others, 1957) and found to range from
57.1 in an olivine basalt sample to 4.9 in a
FIGURE 7-Clospup oF BASALTDrKEsHowN rN Flc
trachyte. Many of the olivine basalts and all of
6; note dense nature of basalt and vertical jointthe intermediate rocks in the Palomas volcanic
lng.
field have SI values less than 35. Renault
(1970) reports that SI values less than 35 are
thought to result from differentiation of
basaltic magma within the crust. Several
olivine basalt samples have values of SI
greater than 35 which implies little or no differentiation. The lack of differentiation in
some of the olivine basalts suggeststhat they
were transported from the mantle in a relatively short period of time, whereas the other
olivine basalts and intermediate rocks previously mentioned probably resided in a magma
chamber in the crust long enough for significant differentiation to occur.
The presenceof high-pressure phase xenocoNcENTRICALLYoRIENTED
FIGURE 8-DrNsr.
crysts such as enstatite and feldspar are furJOINTING
IN BASALTTOEORPILLOWSTRUCTURE,
EX.
ther evidence that some of the basalts were
posed in roadcut approximately l5 mi south of
brought to the surface from the mantle in a
Palomas, Mexico. Lighter colored materials are
short period of time.
primarily clay and silt.
The plagioclase-rich rocks (andesites and
trachytes) are older than the olivine basalts
and therefore were emplaced first. These rocks
represent successive tapping of a differentiated magma reservoir. This type of activity
has been suggestedfor the basalts in the nearby West Potrillo Mountains by Hoffer (1976).
The intermediate rocks represent eruptions
from the top of the magma chamber, where
plagioclase and biotite, being less dense than
the magma, concentrated. Later eruptions
were from the lower part of the reservoir
where clinopyroxene, olivine, and densemafic
xenoliths concentrated. This explains the
occurrence of the more differentiated flows
underlying the olivine and clinopyroxene
FICURE
9-Pennllrl-nEDDED
HyDRocLASTlc
phenocrysts, lack of peridotite xenoliths,
PALOMAS
M A T E R I A LO
S V E RAI I N B Y D E N S EB A S A L TT; O A d C u t
approximately 15 mi south of Palomas, Mexico.
(continued on p. lQ
Where
tobuyUSGS
topographic
maps
Palomas
volcanic
field
(continued from p. 8)
The following dealerscarry a selectedinventorv of
U S G S 7 % m i n a n d l 5 m i n t o p o g r a p h i cq u a d r a n g l e
maps of their respectiveareas:
Mountainsand Rivers
2320 Central Ave. SE
A l b u q u e r q u e ,N M 8 7 1 0 6
The Trailmaster II
5401 Central Ave. East
A l b u q u e r q u e ,N M 8 7 1 0 8
Backwoods
6307 Menaul Blvd. NE
A l b u q u e r q u e ,N M 8 7 1l 0
The WildernessCentre
2421 San Pedro NE
A l b u q u e r q u e ,N M 8 7 1 l 0
S a n d i aM o u n t a i n O u t f i t t e r s
For Wilderness People
961I Menaul Blvd. NE
Albuquerque, NM 87 I I 2
Holman's
401 Wyoming Blvd. NE
A l b u q u e r q u e ,N M 8 7 1 2 3
Trico International
PO Box l5l9l
Rio Rancho Plaza
R i o R a n c h o ,N M 8 7 1 7 4
Gallup Blueprint
303S. 2nd
Callup, NM 87301
San Juan Reproduction Co.
1 3 5N . A i r p o r t D r i v e
Farmington, NM 87401
Alpine Sports, Inc.
l2l Sandoval
Santa Fe, NM 87501
BaseCamp
l 2 l W . S a n F r a n c i s c oS t .
Santa Fe, NM 87501
Healy-Mathews Staioners, Inc.
5 1 5 C e r r i l l o sR o a d
S a n t aF e , N M 8 7 5 0 1
Wilderness Bookstore
P O B o x 3 2 1 ,E l P r a d o
Taos, NM 87529
Los Alamos Stationers
1907Central St.
Los Alamos, NM 87544
The Trailmaster
W h i t e R o c k S h o p p i n gC e n t e r
Los Alamos, NM 87544
M a x a e ' sB o o k s
Bent Street
PO Box 1836
Taos, NM 87571
S i e r r aS p o r t s ,I n c .
3 0 7S . P u e b l o R d .
Taos, NM 87571
Taos Mountain Outfitters
Box 1862
Taos, NM 87571
The Paint & Print Shop
1 2 0N . 2 n d S t .
Raton, NM 87740
Bill's Pack Rat
200Austin St.
Truth or Consequences,NM 87901
Montgomery Ward
522Broadway
T r u t h o r C o n s e q u e n c e sN, M 8 7 9 0 1
OCS Sporting Goods, Unlimited
406 Broadway
Truth or Consequences,NM 87901
Blueprints & Maps
1 2 0S . W a t e r
L a s C r u c e s ,N M 8 8 0 0 t
D o n a l d H . W i e s e& C o .
525 S. Melendres
Las Cruces, NM 88001
Culak Surveying, Inc.
1 2 1W e s t H e m l o c k
Deming, NM 88030
The WildernessSociety
Catwalk Road
Glenwood, NM 88039
H e r b W a r k i n sS u r v . & M a p p i n g
5 1 5M a r k e t S r .
PO Box 472
Silver City, NM 88061
Silver Sports
I l6 N. Bullard
Silver City, NM 88061
Vic Topmiller, Jr.
1 6 0 9N . G o l d
PO Box 201
S i l v e rC i t y , N M 8 8 0 6 1
R o s w e l lM a p & B l u e p r i n t C o . , I n c .
4 1 0N . M a i n
Roswell, NM 88201
T e x S p o r t i n g& P a w n
307 West Mermod Street
Carlsbad, NM 88220
Pat's Sporting Goods
Box I 633
Ruidoso, NM 88345
significantly lower MgO concentration, total
Fe content, and higher SiO, and alkali content
of the andesites and trachytes relative to the
olivine basalts.
References
Balk, R , 1962, Geologic map of Tres Hermanas Mountains: New Mexico Bureau of Mines and Mineral
Resources,Geologic Map 16, scale l:48,000
Frantes, T. J., 1981, The geology of the palomas volcanic
field, Luna County, New Mexico, and Chihuahua, Mexico: University of Texas (El Paso), M.S. thesis, p. 70
Hawley, J. W., 1981, Pleistocene and Pliocene history of
the international boundary area, southern New Mexico,
rn Geology of the border, southern New Mexico-northern Chihuahua: El Paso Geological Society, Field Trip
Cuidebook, p. 26-32
Hoffer, J. M., 1976, Geology of the porrillo Basalt field,
south-central New Mexico: New Mexico Bureau of Mines
and Mineral Resources,Circ. 149, p. 30
Kuno, H., Yamasaki, K., Iida, C., and Nagashima, K.,
1957, Differentiation of Hawaiian magmas: Japanese
Journal of Geology and Geography, v.29, p. 179-218
Lowman, P. S., and Tiedemann, H. A., 1968. Terrain
photography from Gemini spacecraft-Final
geologic
report: Goddard Space Flight Center, X-644-71-15. D.
t4-23
Renault, J., l9?0, Major-element variations in the potrillo,
Carrizozo, and McCarthy's basalt fields, New Mexico:
New Mexico Bureau of Mines and Mineral Resources,
C i r c . | 1 3 , 2 2p .
Robinson, B. R., and Clark, K. F., t981, Reconnaissance
geology of the Sierra Alta-Boca Grande area, Chihuahua, Mexico: El Paso Geological Society, Field Trip
G u i d e b o o k ,p . 6 2 - 6 3
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