of theHayner
diagenesis
Mechanical
andchemical
(Santa
Fe
Valley
Formations
Ranch
andRincon
NewMexico
Miocene),
SanDiegoMountain,
GrouF,
NM88003
LasCruces,
NewMexico
StateUniversity,
Deparlment
of EarthSciences,
byGregH. MackandJeffryD. Grigsby,
Introduction
The Santa Fe Group in New Mexico consistsof nonmarine, syntectonicdetritus that
was deposited during formation of the Rio
Grande rift. In southern New Mexico two
major periods of rifting are recognized
(Seager,1975).The initial stageoccurredduring Miocene time and resulted in large,
northwest-trending, closedbasins, which received several thousand meters of fanglomerateand playa shale and gypsum. The latter
stage of rifting (Pliocene and Pleistocene)
segmentedsome earlier rift basins, produced
north-trending basins and uplifts, and culminated in integration of the Rio Grande
drainage. The Santa Fe Group is an important ground-water and hydrothermal aquifer
in southem New Mexico. and efficient use
of these resourcesrequires an understanding
of its stratigraphy, sedimentology, and diagenesis.Toward this end a study was undertaken to unravel the diagenetic history of
early basin-fill sandstones of the Santa Fe
Group at San Diego Mountain, New Mexico.
The San Diego Mountain section is well
suited for study becausemany of the variables that are influential in diagenesisare constant throughout the section. For example,
the 950-m-thick section is almost continuously exposed,with less than ljVo covered,
which allows for systematic vertical sampling. There also was little change in provenancethrough time. Andesitic volcanic rocks
were the dominant source, although a minor
sedimentary contribution in the upper 150
m of the section is indicated by the presence
of detrital quartz, chert, and carbonate-and
pelitic-rock fragments. Grain size was also
held constant by restricting the samplesto
medium-grained sandstone. Furthermore,
facies analysis indicates that there was little
changein depositional environment through
'
#
l
r
.
i
- )time. The sedimentwas depositedby sheett:
flood and streamflood processesin a mid"?
fan or distal-fanenvironment. Thus, diage;.
Rincon
s
netic trends in the section should be pri|
.+.= marily a function of depth of burial and poreDiegoMtn.
".""
i
J s"Siert
?A
solution chemistry.
DofroAno
A variety of diageneticfeatures,both me''f Mrs.
chanical and chemical, is found in Santa Fe
;"':!
.
Group sandstoneS.Many of the featuresat
San Diego Mountain were described previously by Walkeret al. (1978)aspart of a larger
study of the diagenesisof first-cycle,desert
alluvium. This study systematically documents spatial and temporal relationships
among the mechanical diagenetic features,
1 a"""'"',.
.onih such as compaction and clay infiltration, and
the chemical diagenetic features, such as
dl
hematite and the various cements, in order
+'"' iT,*,,,.
:ll:=
to developa comprehensivediageneticmodel
t ..sWest Potrillo ,j
for the Santa Fe Group at San Diego Mounml
Mts.
km
tain.
i
Methods
Forty-seven samples of medium-grained
sandstone were collected from outcrops at
20-m intervals over a 95O-m-thicksection of
the lower Santa Fe Group at San Diego
Mountain, New Mexico (Fig. 1). At this lo-
.g,.5*iiil,.,il
llq"e'lq,l""
t. I
i"i."fii
N=""'+:
I '.:
5,
i ","
cation the lower SantaFe Group is composed
of the basal Hayner Ranch and overlying
Rinr:on Valley Formations, both of Miocene
age,Beforedepositionof the uppermost forniation of the-Santa Fe Group (Camp Rice
Formation; Pliocene and Pleistocene), the
Hayner Ranch and the Rincon Valley Formaiions were uplifted and tilted about 45'
southward (Seageret al., t971).
Thin sections of the 47 samples were examined for detrital grain types, texture, and
authigenic minerals. Detrital modes were de-
contacts were observed.
ft
Alsoin thisissue
potentialin
Mineral-resource
p. 50
NewMexico
on Hydrogeologic
Commentary
crosssecfionthrough
SunshlneValley,Taos
p. 54
County,New Mexico
p. 56
Tuff
KneelingNun
study
Ground-subsidence
for
and recommendations
on collapsible
construction
p. 59
soils
p. 63
Service/News
p. 64
NMGSabstracts
p. 68
Staffnotes
soon
Goming
of zonedgarnets,San
Geochemistry
Pedromine,SantaFe County
Vertebrate
faunaof U-BarCave
T o po
T o pO
t00
200
300
o
(t,
Q'
300
400
at
!
500
6
=
40
500
600
600
700
700
800
800
900
900
too0
Bose
o
rooo
to
20
30
40
50
60
70 80
90
too
Bose O
ro
Percenfoge
FIGURE 2-Packing prorjmity (solid line) and packing density (dashed
line) as a function of stratigraphic position.
Phyllosilicatecementwas identified by use
of an x-ray diffractometer and an energy-dispersivescanningelectronmicroscope(SEM).
Sample preparation for x-ray analysis was
done according to Carrol's (1970)method,
which includes glycolatedand unglycolated
runs. Belk's (1,974)eneryy-dispersive SEM
techniquewas used. Thin sectionsalsowere
examined with a Nuclide ELM-28 Cathode
Luminoscope,utilizing a beam energy of 15
kV and a beam current of 0.6 milliamps.
90
loo
FIGURE 3-Percentage of longitudinal grain-to-grain contacts(solid line)
grain-to-graincontacts(dashedline) as a function of
and concavo-convex
stratigraphic position.
section(Fig. 2). Similarly, the percentageof
longitudinal grain-to-grain contacts and the
percentageof concavo-convexgrain-to-grain
contacts display no consistent trends as a
function of shatigraphic position (Fig. 3). The
lack of well-defined vertical trends in compaction parametersis anomalous. Taylor
(1950)demonstratedthat the percentagesof
longitudinal and concavo-convexcontacts
increasedsystematicallywith depth in Cretaceous sandstonesin Wyoming. The absenceof these trends in the Hayner Ranch
and Rincon Valley Formationssuggeststhat
normal compaction was somehow prevented, or that burial depths were not great
enough to produce recognizabledifferences
in compaction.The latter interpretation seems
lesslikely in light of the study by Taylor (1950),
which involved burial depths similar to those
in the SantaFe Group.
Another diageneticfeature of mechanical
origin consistsof clay rims, which display a
tangentialorientationof the long axesof clay
mineralsaround detrital grains (Fig. 4). Clay
rims are found in roughly half of the samples, and their occurrencedoes not appear
to be controlled by stratigraphic position.
Walker et al. (1978)demonstratedthat these
clays are the result of infiltration at shallow
depths of burial, and they are common in
desert alluvium. Locally, the clay rims are
intimately intermixed with hemaiite rims.
Detrital grains
The most abundant detrital grains in the
Hayner Ranch and Rincon Valley Formations
are volcanic-rockfragments (517")and plagioclase(38%);the sandstonesare classified
as feldspathic Iitharenites. Volcanic-rock
fragmenis exhibit porphyritic and microlitic
textures (Dickinson, 1970).Detrital plagioclase and plagioclase phenocrysts in rock
fragments display oscillatory zoning and
twinning, and they have an anorthite content that rangesfrom 36 to 437o(andesine),
as determined by the Michel-Levy method.
Detrital quartz is uncommon (6Vo) and is
found in greater than trace amounts only in
the Rincon Valley Formation. Most of the
quartz grains are monocrystalline. Minor
amounts of detrital chert (2Vo),pelitic-rock
fragments (1.7%), and carbonate-rockfragments (0.3%) also are found in the Rincon
Valley Formation. The other lVo of the framework grains is biotite, hornblende, and
Chemical diagenesis
oPaquemrnerals.
Hematiterims
Almost all detrital grains in the Hayner
Mechanical diagenesis
Ranch and Rincon Valley Formations are
There is little variation in the compaction rimmed by dark-red hematite. Walker et al.
parametersas a function of depth of burial (1978) established a diagenetic origin for
(Figs.2,3). Packingproximity shows a slight hematite rims in Cenozoicdesert alluvium,
increasetoward the base of the section,but including the Hayner Ranch and Rincon Valpacking density displays no increasedown- ley Formations.Hematiteformed earlyin the
August 1985 New MexicoGeology
20 30 40 50 60 70 80
P e r c e n l og e
burial history of the sandstones,becauseit
is the first authigenic mineral to rim detrital
grains. Locally, hematite is intermixed with
tangentiallyoriented clay, indicating that at
least some of the clay infiltrated simultaneously with the creation of authigenic hematite.
New AAexuc@
GEOLOGV
o Science
andSeruace
Volume 7, No. 3, August 1985
Edifor:Deborah A. Shaw
Published quarterly by
New Mqico Bureau of Mines and Mineral Resources
a division of New Mqio Instihrte of Mining & Tchnology
BOARD OF REGENTS
Ex Officio
Toney Anaya, Gouqnorof Nru Mexico
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ADpointed
Steve Torres,Pi;s., 1967-191, Socorlo
lTreas.,7977-1987,Ias Cruces
Judy Ftoyd, Sec.
Gilbert L. Cano, 1985-1997,Albuquerque
Lenton Malr, 1985-1989,Albuquerque
Donald W. Morris, 1983-1989,Ins Alamos
New Mexico lnstitute of Minint & Technology
Laurence H. Lattman
Pr5idilt . .
New Mexico Bureau of Mines & Mineral Resources
D i r e c t o. r.
.......
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......
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Georges.Austin
Subsriltiots: Issued quartedy, February, May, Augtst,
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November; subscription price $6.O0/calendar
Editotialmttq : Contributions of matedal for consideration
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longer than 20 typewritten, double-spacedpages. Addressinquiries to DeborahA. Shaw, editor of Nru Meri@ Geolory,New Mexico Bureau of Mines & Mineral
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qs publicdomin, thereforcreprorlucible
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Cements
Calcite cement is found in all but two of
the thin sectionsexaminedin this study. Calcite is commonly coarse grained and occasionally exhibits a poikolitic texture (Fig. a).
In some samples calcite almost completely
fills all of the original pore spaces,whereas
other calcite-cemented
samplesare quite friable. Calcite may also replacevolcanic-rock
fragments,plagioclase,and hornblende, al-l,Vo
though less than
of the grains are affected.
Examination of calcite cement with the
cathode luminoscope reveals two types of
luminescence.The oldest cement, closestto
the detrital grains, luminesces moderately
bright to dull orange,and there is a tendency
for the brightness to diminish systematically,
but without distinct zonation, toward the
center of pore spaces.In about half of the
samples,the youngestcalcitecement,which
occupiesthe center of pore spaces,is nonluminescent.Luminescenceof calciteis due
primarily to the Mn/Fe ratio (Frank et al.,
1982;Grover and Read, 1983;Fairchild, 1983).
Manganeseis an activator ion and causes
luminescence,whereas ferrous iron inhibits
luminescence.Orangeluminescenceimplies
the presenceof Mn-' and Fe*2 in subequal
amounts in the calcite cement. The lack of
luminescenceindicatesthe absenceof Mn*'
and Fe*2 or a very low ratio of Mn*' and
Fe*2.
Calcite cement postdates hematite rims and
most clay rims. However, in one sample an
infiltrated clay rim coated the edge ofa calcite-cement crystal that was growing into an
empty pore space (Fig. a). This textural observation suggests that at least some of the
calcite cement precipitated early in the diagenetic history of the sandstones.
Phyllosilicate cement occurs sporadically
in the Hayner Ranch and Rincon Valley Formations, and it is the dominant cement in
only two samples. Phyllosilicate and calcite
cements are never found together in the same
pore space, although one portion of a thin
section may be cemented by calcite and an
burial proceeded,sediment passedsequentially from shallow stageI diagenesisto deeper
stageII diagenesis.StageIII, however, is associatedwith regional uplift and postdates
stagesI and IL
The earliest stage involves the development of hematite rims by interstratal solution of magnetite, biotite, and amphibole,
the infiltration of clay matrix, and minor
compaction.This stageis discussedin detail
by Walker et al. (1978).The precipitation of
hematite indicatesthat pore fluids in stageI
were oxidizing.
The secondstageof diagenesiswas dominated by the precipitation of cement, principally the orange-luminescentcalcitecement,
but alsocalciumsmectiteand quartz cement.
At leastsomecalcitecementationoverlapped
in time with infiltration of clav,and thus some
of the calcitecement was relativelv earlv in
the burial history. The "early" precipitaiion
of some calcite cement may account for the
anomalouslylow amount of phyllosilicatecement and for the lack of significant stratigraphic trends in compaction. Calcite
cementationwould inhibit the precipitation
of phyllosilicatecementby filling pore spaces
and limiting the chemical interaction between detrital grains and pore solutions.An
"earIy" calcite cement also would inhibit
compactionof detrital grains by providing a
relativelyrigid framework. The stateof compaction inherited from stageI would persist
through deeper levels of burial.
The composition of authigenic phasesallows speculationon the chemishy of the pore
solutions during stage II diagenesis. The
presenceof both Mn'2 and Fe*' in the calcite
iement, indicated by orange luminescence,
Interpretation of diagenetichistory
suggeststhat the pore solutionswere reducThe diagenetichistory of the Hayner Ranch ing (Groverand Read, 1983).The increasing
and Rincon Valley Formationsat San Diego dullnessof the luminescencetoward the cenMountain canbe separatedinto three stages. ter of the pore spacefurther indicates that
Each stageis characterizedby a unique set the pore solutionsbecameprogressivelymore
of processes,authigenic phases,and ground- reducingthrough time. The changefrom oxwater chemistry. StagesI and II were prob- idizing pore solutions in stageI to reducing
ably going on simultaneously but at different pore solutions in stage II is consistentwith
depths within the basin. As deposition and
adjacentportion by phyllosilicate.There does
not appear to be a stratigraphiccontrol on
the distribution of the phvllosilicatecement.
The phyllosilicatecembn[has white to gray
birefringenceand extendsas blade-likecrystals into the pore spaces(Fig. 5). Analysis by
x-ray diffraction and by energy-dispersive
SEM indicatesthat the phvllosilicateis calcium smectite(Crigsby,'19b4).
The smectite
cement postdates hematite rims and infiltrated clay matrix. The paucity of phyllosilicatecementin the Hayner Ranchand Rincon
ValleyFormationsis anomalous.Feldspathic
litharenitesderived from intermediateto mafic
volcanic rocks commonly are cemented by
phyllosilicates.An important sourceof ions
for the clays is chemicalbreakdown of detrital feldspars and volcanic-rock fragments
(Galloway, 1974;Wllson and Pittman, 1977;
Davies et aI., 1,979).This process was obviously inhibited in the Hayner Ranch and
Rincon Valley Formations.
Quartz and feldsparcementsare very uncommon in the Hayner Ranch and Rincon
Valley Formations.Quartz cement is found
only in the Rincon Valley Formation, where
it occurs as overgrowths around detritalquartz grains and postdateshematite rims.
The paucity of quartz overgrowths is probably a function of the paucity of detrital quartz
to act as nuclei. Feldsparcement also occurs
as overgrowths,but it is extremelyrare and
will not be consideredfurther. Anomalous
by their absenceare zeolites,specificallythe
calciumzeoliteslaumontite and heulandite,
which are common as alterationproducts and
cements in volcanicarenites(Merino, 1975;
Surdam and Boles, 7979;Davieset al., 1979).
FIGURE 4-Photomicrograph of sandstone of the Hayner Ranch Formation
exhibiting detrital volcanic-rock fragments, infiltrated clay rims (arrow), and
coarse calcite cement (C). Calcite cement crystal, which was growing into
empty pore space(black), is rimmed by infiltrated clay. Scalebar is 0.25 mm.
FIGURE S-Photomicrograph of sandstone of the Hayner Ranch Formation,
composed of volcanic-rock fragments and plagioclase. Smectite cement is
growing into empty pore space (black). Scalebar is 0.25 mm
NewMexicoGeology August 1985
quarlz
solurolion
quorlz
solurolion
Virginia: American Association of Petroleum Geologists, Bulletin, v. 67, pp. 1275-1,303
Kahn, J S., 1956,The analysisand distributioh of the
loooc
rtoooc
propertiesof packingin sand-sizesediments-pt. 1;On
25.C1
the measurementof packing in sandstones:Journalof
Anorlhite i
tl
Geology, v 64, pp 385-395
Loumontile
+
+ 20
Merino, E., 1975,Diagenesisin Tertiary sandstonesfrom
I
I
Kettleman North Dome, California-Il; Interstitial soN
N
I colciumlutions-distribution of aqueous speciesat 100.C and
l8
chemical relation to the diagenetic mineralogy: Geochimica et Cosmochimica Acta, v.39, pp. 1629-1,645.
N
N
t6
Seager,W. R., 1975,Cenozoictectonicevolution of the
o
o
(J
(J
Las Cruces area, New Mexico: New Mexico Geological
o
o
P692"J9-3.5
ro
t4
Society,Guidebookto 26th Field Conference,pp.1+tF
ctt
or
250.
o
' 5- oo
J
t2
Seager,W R, Hawley, J W, and Clemons,R E ,1977,
J
- c ol c i t e
-9 q,
ots
Geologyof SanDego Mountain area,Dona Ana Coun$,
iror",o:r,
Q6
New Mexico: New Mexico Bureau of Mines and Mineril
to
Resources,Bulletin 97, 38 pp
Gi b b s i t e
S u r d a m ,R C , a n d B o l e s , J R , 1 9 7 9 , D i a s e n e s i s o f v o l phyllile
I
canic sandstones:Societyof EconomicPaleontologists
-8-7-6-5-4-3-2-to
-5
-4
and Mineralogists,SpecialPublication26, pp.227:242.
-3
-2
L o go H o s i o e
Swanberg,C. A., 1976,Geothermalstudiesin southwest
Lo9oHasioc
New Mexico: New Mexico Energy Institute, Technical
Completion Report 3, 54 pp
FIGURE
Taylor,J M, 1950,Pore-spacereduction in sandstone:
!-0"ft diagram)Activity diagramin the systemCaO-ArO3-SiOr-HrOat 25.C,1,be|I,and unit
activity of water.Freeenergydata usedin constructionof diagramis fro- br.uu, ( 1982).Verticaldashed
Amer.icanAssociation of Petroleum Geologists, Bulletin, v. 34, pp.701-706
lrnesrePresentquartz saturationat the temperaturesindicated,and horizontal dashedlines represent
calcitesaturationat the valuesof P.o,indicated.Data points are modern subsurfacewater compositions Walker,T R, Waugh, B , and Crone, A, J , 1978,Diagenesisin first-cycle desert alluvium of Cenozoic age,
from the san Diego Mountain area,'takenfrom swanberg(7976)and wilson ei al. (19g1).
southwesternUnited Statesand northwesternMexico:
GreologicalSociety of America, Bulletin, v 89, pp i9FIGURE 7-(right
diag^ram)Activity diagram in the system cao-A!o.-sio,-H,o
unit activity of water. SeeFig. 6 caption (above)for further explanation.
at 25.c, 1 bar, and
changesin the oxidation potential of modern small amountsat all stratigraphiclevels.The
ground water from the surfaceor edgeto the model that best fits these constraints incenter of depositionalbasins (Champ et al.,
7979).
The chemistry of stage II pore solutions
can be defined further by the-useof activitv
diagramsin the system CaO-Al,Or-SiOr-H,O
(Figs.6, 7). StageII pore solutions,assuming waters.
equilibrium,must have been in the calcium
smectitefield and near the calcitesaturation
References
crystallization.The pore fluids may have been
Champ, D. R., Gulens,J., and Jackson,R. E., 1929,Oxsaturatedwith respectto quartz, but quartz
idation-redu_ction
sequencesin groundwaterflow syscementonly precipitatedin the detritalquartztems: CanadianJournal of Earth Sciences,v. 16,
ip.
bearing Rincon Valley Formation. If this arDavies,D. K., Almon, W. R., Bonis, S. B., and Hunter,
gument is correct, the chemistry of stage II
B. E., 1,979,
Depositionand diagenesisof Tertiary-Holpore solutionscan be fixed at the-intersec"tion ocenevolcaniclastics,Guatemala:
Societyof Economic
betweenthe quartz and calcitesafurationlines
Paleontologists
and Mineralogists,Specialpublication
26, pp.287-306.
Dickinson, W. R., 1970,Interpreting detrital modes of
graywacke and arkose:Journal of Sedimentary petrolo g y ,v . 4 0 , p r . 2 t - 2 9 .
Drever,J. L,'l'982, The geochemistryof natural waters:
Prenti.ce-Hall,Inc., Ne"wJersey,3g'gpp.
_
Fairchild,I. J., 1983,Chemicaliontroli-of cathodoluminescenceof nafural dolomitesand calcite-new data
_ and r-eview:Sedimentology,v. 30, pp. 579-583.
Frank,J..R,,Carpenter,A. 8.. and Ogiesby,T. W., 1982,
Latnodoluminescence
and composition of calcite cement in the Taum Sauk Limestone(Upper Cambrian),
southeastMissouri: Journal of Sedimentary petrology,
v. 52, pp.631-638.
Galloway,_
W. E., 1974,Depositionand diageneticalteration of sandstone in northeast Pacific aic-related ba-
The final stageof diagenesiscorresponds
to the time of precipitation of the nonluminescent calcite cement. The absenceof luminescencein calciteindicatesthe paucity of
Mn*2 as a result of oxidizing ground waiers
(Grover and Read, 1983).Furlhermore, the
nonluminescentcalcite cement is found in
August 1985 New MexicoGeology
mrnescencepatterns, Middle Ordovician carbonates,
Wilson,M. J., and Pittman, E D.,7977,Authigenicclays
in sandstones-recognition and influence on reservoir
propertiesand paleoenvironmental
analysis:Journalof
Sedimentary Petrology, v. 47, pp. 3-31.
Wilson, C. A., White, R. R., On, B R., and Rovbal, R.
G., 1981,Water resourcesof the Rincon and-Mesilla
Valleysand adjacentareas,New Mexico:New Mexico
StateEngineer,TechnicalReport 43, 514pp
Tl
NewMexico
Geological
Society
news
At the annual NMGS businessmeetins
inApril membersvoted to return to the 198i
dues structure for 7986, which will mean
$7.00 dues for active members, $5.00 for
associatemembers,and $3.00for students.
A subscription to New Mexico Geologywill
no longer be included as part of tha-dues
payment. Members are, however, urged to
continue to subscribeto the magazine,and
it has been suggestedthat subscliptionnotices be included in NMGS mailings. The
societywill award a total of $8,500in 1985
to studentsstudying New Mexico geology.
The societyfellowship, worth $1,0b0,w;s
given to Richard P. Lozinsky of New Mexico
Tech. Twenty-six other students will share
the remaining $7,500.Twenty-sevenpapers
were presentedat the spring meeting technical sessions (seeabstracts, pp. 6a-67),
which were organized by John MacMillan.
A{ter the meeting, a field trip was led by
Clay Smith to the ore districts near Socorro.
Ron Broadhead, who was registration
chairman. reported that 104 geoi6gists registeredfor the meeting,and GeorgeAustin,
who was general chairman, indicated that
the meeting essentially broke even financially. Specialattention is called to the NMGS
fall field conference to be held September
26-28 in the SantaRosa area. NMGS members will receive notices about the conference this month. SpencerLucas and Barry
Kues of the Univerlity of New Mexico ar'e
in charge of the field trip, and questions
may be directed to them.