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mining
in Mogollon
Temperature
of mineralization
NewMexico
andvicinity,
southwest
district
R Kent,Kevin
Department
andGeological
Engineering,
J. Bornhorst,
L. Mann,andScotlR. Bichey,
of Geology
by Theodore
Gretchen
Michigan
Ml 49931
Technological
University,
Houghton,
50 doubly polished thin chips from the Mogollon mining district and vicinity. Suitable
fluid inclusions were found in 21 samples
(Table2).
Typical inclusions consist of liquid with a
small vapor bubble. Most visible inclusions
are irregular in shapeand less than 0.04mm
in diameter.Fluorite containscomparativelv
large,isolatedinclusionswith negitive crystal shapesthat we interpret as primary. In a
sample of fluorite from Sacaton,a negative
TABLE l-Hypogene vein-filling minerals in the
Mogollon mining district, southwest New Mexico crystal-shapedinclusion had dimensions of
(compiled from Ferguson, 1927).
up to 0.2 mm on a side. Most primary inclusionsin the fluorites were about 0.04mm
Nonmetallic
in cross section. Obvious secondary incluMetallic minerals
minerals
sions in fluorite were generally small (less
than 0.08mm in diameter)and followed fracStromeyrite
Pyrite
Quartz
tures. Inclusions in calciteand quartz were
Calcite
Chalcopyrite Chalcocite
Fluorite
Tetrahedrite
Galena
Iesseasvto classifvbecausethe mineralsare
Adularia
Pyrargyrite
Sphalerite
highly iractured. Most inclusions followed
Rhodochrosite
Bornite
Specularite
fracture and/or cleavageplanes. Inclusions
Chlorite
Argentite
for analysis were selectedbecauseof their
isolationand shape;none of theseinclusions
showed evidence of necking. The fluid inclusionsanalyzedin calciteand quartz may
Fluid-inclusion studies
be primary, pseudosecondary,or,lesslikely,
Fluid inclusions represent mineralizing secondary.Definite secondaryinclusions in
samplesF-6 and C-2 were homogenizedat
fluids trapped in minerals. Studies of fluid
inclusions can provide data about the tem- temperaturesbetween 145 and 170'C, and
p e r a t u r e a n d c o m p o s i t i o n o f t h e f l u i d s they were homogenizedin sample PC-1 at
(Roedder,7979).\Nehave looked at more than temperaturesbetween 100and 160"C.These
temberaturesare lower than temperatures
reported in Table2. We believe the fluid-indata reported are representativeof
clusion
M o g o l l o nm i n i n gd i s t r i c t
the main stageof mineralization.
The salinitiesof the fluid inclusions were
Cooney
determined from the freezing-pointdepression, and they are expressedas equivalent
A
weight percent NaCl (Table2). The compoof the inclusion fluid was determined
,or-_.| T . I O S sition
in four samplesof fluorite by leachingcrushed
sampleswith deionized water followed by
rO MbgolIon
atomic-absorptionanalysis(Table3). The leacir
::
:t:
:::
l::
solutionsrepresenta sampleof both primary
R,I9W
l1'.'1'1,f.
and secondaryfluids. Within the optical size
IIIS
l. ...c
B ur s u m c o l d e
range of our microscope (>0.001 mm di\,,,,,,,,E,
G l en w o o d
;^
c.ulc.[g
ameterinclusion),fluorite from the Goldspar
i : 5 p r u c eL r e e K
prospecthas roughly equalamountsby volR20W
1,: e
\ ::Y::
ume of primarv and secondarv inclusions.
:. o:n:e:P:r-n .e
\
o-L---CIf------J
5
\,,,,,,,,9j,,
whereas'the
ofher samnlesanalvzed have
II25 \
)n
\r ::::
c o l d e r c . m o -r q i n
O
*
S
"L IjDJ
greaterthanTSVosecondaryinclusions.The
PineCret
./
, , , (, ,
secondaryinclusions in our samplesgenerO mine/prospect
ally are smallerthan the primary ones so we
C town
optimized crushing size for the best extracTI3S,
9s lreDcA
tion of primary fluids.
t foull
Introduction
Cenozoic mineral deposits are scattered
throughout southwest New Mexico. These
depositsare typically baseand preciousmetals and often are associatedsnatiallv with
mid-Tertiary volcanic centers'(Elstonand
others, t976;EIstonand Erb, 1979).The mineralization in the Mogollon mining district
consistsof Ag-Au- (Cu-Pb-) bearing veins
that were open-spacefillings along pre-existing faults. Hypogeneore and ganguemineralsof the district are listed in TableL; quartz
and calciteare the principal vein-filling minerals. Ferguson(1927)recognizeda general
parageneticsequencefor the entire district
with quartz followed by calcite and then
fluorite; there is a gradual transition from
one mineral to the next. Where fluorite is
abundant, precious-metal mineralizaton
generallydoes not occur. Hypogene mineralizationwas followed by supergeneenrichment. A detailed description of the district
can be found in Ferguson (1927).
The Mogollon mining district is situated
spatially on the margin of the Bursum caldera (Fig. 1). Recentradiometric age dating
of mineralizationat Mogollon has shown that
thesedepositsare approximately15 to 18m.y.
old (Kent, 1983;Rattd and others, 1983;Ratt6,
1981).Silicic volcanic activity related to the
Bursum calderaoccurredfrom about 25 to 28
m.y. ago (Ratt6, 1981).Located south and
eastof the Mogollon mining district are various small mines and prospectswith associated hydrothermally altered rocks (Fig, 1;
seeRatt€ and others, 1979). One of these
mines, the Lone Pine mine, is noted for the
occurrenceof native tellurium (Ballmer,1932).
tr
Y
R.I9W
$"ff,
f
R ,1 8 W .
R.t7W
boll on downthrown
side
oreo
of hydrothermol
l;il
H
ollerotion
FIGURE l-Location map of study area, Mogollon mining district and vicinity, southwest New Mexico.
Location of mines and prospectsalong the southwest margin of the Bursum calderaare shown; the
Mangastrench, a basin and range graben,is south of the caldera.
Discussion and summary
The homogenization temperaturesof the
fluid inclusionsshow a progressivedecrease
in temperafure with time based on the generalized parageneticsequenceof quartz to
[?
Nm MexicoGeology August 1984
53
TABLE2-Homogenization temperaturesand salinity determined on fluid inclusions from the Mogollon
mining district and vicinity, southwest New Mexico. *Variable gas/liquid ratios and temperatures reported represent minimum ratros.
Homogenization
temperature
Description
Sample
Fanney mine
F-1 (surface)
F-3 (900 ft level)
F-6 (900ft level)
F-21 (surface)
Salinity
Nurnber
Number
Mean salinity
of
Range Mean
of
("C)
('c) inclusions (equiv. wt.% NaC
inclusions
Quartz
Quartz
Calcite
Calcite
5
8
9
1
202-258
795-248
204--228
227
277
224
241
3
7
3
3.4
3.4
3.4
Quartz
Quartz
6
I
249269
254-271
260
262
3
2
3.4
Eberle mine
EU-3 (200 ft level)
EU-3a (200 ft level)
EU-4 (200 ft level)
EU-4 (200 ft level)
E-34 (200 ft level)
E-35 (200 ft level)
Fluorite*
Fluorite*
Quartz
Calcite
Calcite
Calcite
3
4
183-185
758-166
2
J.Z
Z
LJT_Z+J
1
J.J
7
3
3
210-235
205-227
784
762
237
241
235
a1 ^
a
Gold Spar
RC-1
RC_2
Fluorite, white
Fluorite, green
10
6
764-789
780J76
176
202
4
2
Pine Creek
PC-1
Fluorite, green
7
764-177
172
3.4
Holt Gulch
HG_1
Fluorite, green
6
762-778
171
J.J
Fluorite, green
Fluorite, white
3
6
164-767 166
160-170 t63
No. of
determinations
Confidence mine
c-2
c-3
1A
1
J,Z
J.J
3.4
Sacaton
s-1
s-2
3.3
140
180
220
260
300
Homogenization temqerature
tC
Lone Pine
LP_1
LP_2
Fluorite, white
Fluorite, green
5
3
157-165 161
178-181 179
SpruceCreek
85-1
Fluorite, green
8
183-209 791
enization temperatures in quattz, calct'te, and fluorite, roughly in Paragenetic order from oldest to
youngesi. No pressure corrections were applied.
calciteto fluorite (Fig. 2). The data fot qtartz
suggesta bimodal distribution in homogenization temperatures.The lower peak may
representsecbndaryfluid inclusionsformed
during late calciteor early fluorite mineralization. No inclusionswere found in samples
that are believed to be the earliest formed
quartz, thus the initial mineralizing,fluids
may have been hotter than indicated by the
samplesanalyzed. Salinity values show no
consistenttrend with time, and they cluster
around 3.3 weight PercentequivalentNaCl
(Fig. 3). The Na/K ratios of extracted primary/secondaryinclusion fluid are between
0.6 and 2.5. Thesevalues fall within the low
range of those reported for mineral depositl
by Roedder (1979). The relatively high-K
contentof thesefluids is consistentwith the
strongK-metasomatismof vein host rocksin
the district(Kent, 1983).
The gas/liquid ratio for inclusions within
individual samples is reasonably constant,
except for fluorite samples from the Eberle
mine. Isolated,negativecrystal-shapedinclusionswith variablegasiliquidratios and
up to 90volume percenigashive beenfound
in two samples of fluorite from Eberle mine.
However,in thesesamplesthere are also nu-
merous negative crystal-shaPedinclusions
that are clearly connectedto fractures and
have leaked. Thus, it is possible that the
variable gas/liquid ratios in isolated inclusions are due to leaking along fractures that
arenow healedand/or too smallto be visible.
Variablegasiliquid ratios, if Primary, would
suggestthat the fluid was boiling during
fluoilte deposition.At the Eberlemine quartz
was deposited at a temperatureof 240"Cor
more fiom fluids that apparently were not
boiling. A lower temPerature fluid that
had boiled during fluorite deposition (150180'C) would have required a combination
of the following conditions during quartz to
fluorite mineralization: 1) a change from
lithostatic to hydrostatic pressure (Pn'ia Z
2) a dramatic drop in hydrostatic
Prigrosta6c)j
pressureif the vein was oPen to the surface;
and/or 3) a significant amount of erosion'
Becausethe origin of the variable gas/liquid
ratiosis disputable,we believethat the fluids
probably were not boiling at the depth of
Eberlemineralization.A pressureof more than
33 bars is required to prevent boiling during
quartz deposition (Haas,1971).In a vein open
to the surfacethis correspondsto a hydrostatic depth of more than 375 m.
Number
of
Mean
inclusions ('C)
Summary
One standard
deviation
Quartz
(high T variety
>238'C)
t9
257
11
Calcite
Fluorite
17
61.
114
11
T4
176
TABLE 3-Composition of fluid-inclusion leach
solutions for flubrites from the Mogollon Mountains in ppm. About 15 grams of optically clean
fluorite were crushed and leachedwith 50 ml of
deionized water. The leach solutions were analyzed by atomic-absorption spectrometry calibrated to standardsolutions.Precisionof the data
is approximately * 57oof the amount determined
for Na and K; it is approximately + 30-50Vofor Mg
and Mn at < 0.05ppm and +70% at > 0.05ppm.
The data presented are normalized to 10 grams of
sample.
Na
K
Mg
Mn
0.6
0.3
0.03
0.03
Holt
Gulch
Pine
Creek
Gold
Spar
0.7
0.5
0.07
0.02
0.5
0.2
0.09
0.08
0.5
0.8
0.3
August 1984 Nm MexicoGeology
3.4
FIGURE2-Histogramsof fluid-inclusionhomog-
A temperatureof about 230"C(uncorrected
for pressure) for quartz and calcite deposition at the current top of the Fanney vein
requires a pressure of more than 27 bars to
prevent boiling (Haas, 1977).In a vein open
to the surface this corresponds to a hydrostatic depth of more than 325 m. The top of
the Fanneyvein today is higher topographically (170m) than the part of the Eberlevein
that was sampled.If one assumesthere was
no structural adjustment after mineralization, then the thicknessof cover during Eberle
mineralizationcould havebeen500m or more.
The hydrothermal fluids responsiblefor the
Cenozoic mineralizationin-the Mogollon
mining district had temperaturesthat iaried
with time from greaterthan 270'C to 180"C.
They had a constant salinity of about 3.3
equivalentweight percent NaCl with Na/K
ratios of 0.6 to 2.5. The temperaturesand
minimum depth estimates of mineralization
and the abundance of base-metal sulfide
minerals in the Mogollon mining district are
typicalof those found in the deeperlevelsof
precious-metal
depositsassociatidwith volcanicterranes(Buchanan,1981).
ACKNOWLEDGMENTS-We
thanK S. D.
McDowell and S. P. Halsor, Michigan Tech,
for their constructivecriticism of tliis manuscript. One of us (Kent) wishes to thank the
New Mexico Bureau of Mines and Mineral
Resources,Socorro, New Mexico, and the
Center of Mining and Minerals Research,
Michigan Tech, for financial support. Dick
Manning and Challenge Mining Company
allowed us accessto the Eberle mine and
other mine dumps in the Mogollon district.
Norbert BIum and Albrecht Schneider,
TechnischeHochschuleAachen, West Germany, graciously provided us with samples
from outside of the Mogollon district. Ted
Eggleston, New Mexico Tech, reviewed this
manuscrlpt.
I t I o .o f
T'
determinatron"I
O
vein mineralization and geochemistry of host rock alteration at ihe Eberle mine, Mogollon mining district,
Ballmer, G. J., 1932,Native tellurium from northwest of
southwestern New Mexico: Unpublished M.S. thesis,
Silver City, New Mexico: American Mineralogist, v. 1,7,
Michigan TechnologicalUniversity, Houghton, Michipp. 491-492.
gan, 84 pp.
Buchanan,L.J.,7987, Preciousmetal depositsassociated Ratt6,J. C., 1981,Geologicmap of the Mogollon quadwith volcanic environments in the southwest: Arizona
rangle, Catron County, New Mexico: U.5. Geological
GeologicalSocieiyDigest,
v. 1,5,pp.237-262.
Survey,GeologicQuadrangleMapl55T,scale"l:24,000.
Elston,W E., and Erb, E. E., 1979,Tertiary geologyo{ Ratt6,J. C., Gaskill,D. L., Eaton,G. P, Peterson,D. L.,
Hidalgo County, New Mexiceguide to metals, inStotelmeyer,R. B., and Meeves, H. C., 1979,Mineral
dustrial minerals, petroleum and geothermalresources:
resourcesof the Gila primitive area and Gila Wilder'l-6.
New Mexico Geology, v. 1, no. 1,,pp.
ness,New Mexico:U.5. GeologicalSuwey, Bulletin 1451,
Elston,W. E., Rhodes,R. C., and Erb, E. E.,7976,Control
229 pp.
of mineralization by mid-Tertiary volcanic centers, Ratt€,J. C., Marvin, R. F., Naeser, C. W, Brooks, W. E.,
southwesternNewMexico:NewMexicoGeologicalSoand Finnell, T. L., 1983, Volcanic history of southciety, SpecialPublication No. 5, pp. 125-130.
westem Mogollon*Datil volcanicfield as recordedalong
Ferguson, H. G., 1927, Geology and ore deposits of the
the Morenci lineament, New Mexico and Arizona: Geological Societyof Arnerica, Abstracts with Programs, v.
Mogollon mining district, New Mexico: U.S. Geological
15, p. 303.
Survey, Bulletin 787, 100 pp.
Roedder,E., 1979,Fluid nclusions as samplesof ore fluids;
Haas,J. L.,Jr., 1971,The effectof salinity on the maximum
thermal gradient of a hydrothermal system at hydroin Barnes, H. L. (ed.), Geochernistry of hydrothermal
stat.icpressure:Economic Geology, v. 65, pp.940 946.
ore deposits, 2nd edition: John Wiley and Sons, pp.
Kent, G. R., 1983,Temperatureand age of preci.ousmetal
648-737.
tr
References
continued from page 52
1-18-84
milt
Operator-Mica Mill, Mica Mine, Mica Inc., Box 2403,
SantaFe, NM 87504;Supt.-Wayne Brown, phone: 8522727; Other official-George Rosen, Box 2422, Santa Fe,
NM 87504
Rio Arriba Co.; private land; ores milled
or refined-mica; capacityof mill:-50,000
tons per day; directionsto mill: 12mi north
of Espanolaon NM-68
2-3-84
limestone
Operator-Herzog ConlractingCorp., 1900GarfieldAve.,
St. Joseph, MO 54503; Gen. Mgr.-Stan Herzog, 1.900
Garlield Ave., St. Joseph,MO &503, phone (816)2339001;Personin charsrFrank Storbakken,P.O. 8ox1936,
Deming, NM, phone: (5057546-2770;Gen. Supt.-Arnold Shipp, 1900 Garfield Ave., St. Joseph, MO 54503;
Other official-Randy Henog, 1900Garfield Ave., St. Joseph, MO 54503,phone (815)233-9001;
Property owner-U.S. Government, Bureau of Land
Management, 1705Valley Drive, Las Cruces, NM 88005
CrantCo.;sec.17,T.245., R. 14W;Deming mining district; federal land; directions to mine: 1.7 mi north of the
intersection of US_10and NM-81
21-84
uranium
Operator-Crownpoint, WestinghouseElectric Corp.,
Uranium ResourcesDiv., Penn Center 3-400, P.O. Box
355, Pittsburgh, PA 15230;Gen. Mgr.-E. ). Miles, WestinghouseElectricCorp.,PO. Box355,Pittsburgh,PA15230;
Gen. Supt.-Salvador Chavez, WestinghouseElectric
Corp., Crownpoint Project, P.O. Box 777, Ctownpoint,
NM 87313;Other official-T. H. Ritner, Westinghouse
Elechic Corp., P.O. Box 355, Pittsburgh, PA 15230;
Property owner-Westinghouse Electric CorPoration
McKinley Co.; sec.24, T.77 N., R. 13 W.;
private land; directions to mine: 0.5 mi
northwest of Crownpoint, NM, on Church
Road
2-10-84
Silver,
lead, zinc
Operator-ProspectN, PICOM Corp., Ltd., P.O.Box361,
El Prado, NM 87529 (company change of name); Gen.
Mgr.-Jmes R. Grainger,sameaddress;Personin charg+
JamesR. Grainger, same address;
Property Owner-James R. Grainger
Siena Co.; sec. 12, T. 13 S., R. 9 W.; Hermosa mining district; federal land; underground; directions to mine: 0.5 mi east on
forest road 157at Wagonbed Spring, 20 ni
south of lVinston, NM, and 1 mi north of
Hermosa, NM
2-1.6-84
sodium
Operator-New Mexico Salt & MineralsCorp., PO. Box
2262, Carlsbad, NM 88220;Gen. Mgr.-Dale W. Janway,
Minesite, NM-31, phone: 745-3558;Gen. Supt.-Herman
Justice,same address;Other officials-Marvin Watts and
Bill Buzbee, Carlsbad, NM;
Property owner-New Mexico Salt & Minerals Corp.
Eddy Co.; sec.18, T. 23 S., R. 29E.;Eddy
mining district; private land; directions to
mine: on NM-31 5 mi east of Loving, NM
2-1.6-84
silica
Operator-LeRoy Jones Mining Co., 1812 Mesquite,
Lordsburg,NM; Gen. Mgr.-Leroy Jones,sameaddress,
phone: 542-9525
Hidalgo Co.; sec. 35, T. 21 S., R. 17 W.;
Gold Hill mining dishict; federalland; directions to mine: 1 mi southeast of WD
3-5-84
Operator-Ki8ht Clay Pit, Kight Construction,P.O, Box
413, Hatch, NM 87937;Gen. Mgr.-Claude Kight, same
address, phone:267-4553; Gen. Supt.-Earl Kight, E.
Henera Rd., Hatch, NM, phone:267-4962;
Property Owner-U.S. Dept. of the Interior, Bureau of
Land Management, Las Cruces, NM 88001
Doia Ana Co.; sec. 23, T. 79 S., R. 4 W.,
state land; directions to pit: 3 mi west on
NM-28 on south side of road
4-3-U
Operator-Clinnken Dagger, Bickerstaff pit, 8513 Marquette NE, Albuquerque, NM 87108;Gen. Mgr.-Hanzle
Janoltona, same address, phone: 2682269;
Property owner-Hanzle Janoltona
BernalilloCo.; T. 10 N., R. 6 E.; private
property; directions to mine: go south 8
mi on NM-214, east5 mi to JuanThomas,
north 2.25mi
Operator-Burro Chief Copper Co., Drawer B, Tyrone,
NM 88055;Gen. Mgr.-Richard E. Rhoades; same address;Gen. Supt.-T. R. Snider;sameaddress;
Property owner-Burro Chief Copper Co., 2500N. Cenhal Ave.. Phoenix. AZ 85004-3015
Grant Co.; sec.15, T. 19 S., R. 15 W; private land; directions to mine: approximately 1 mi southwestof Phelps Dodge
Corp.
oold
3.O 3.2 3.4 3.6
Equivalent weight percent
NaCl
FIGURE3-Histogram of equivalentweight percent NaCl determinedfrom the freezing-pbint
depressionof fluid inclusions.
4-1.5-84
coPPer
(ro necoxrnuro uxr tssur)
New Mexico Geology Augttst 19M