Calc-silicate alteration and sulfide mineralization, San Martin mine, Zacatecas, Mexico

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6273158

Rubin, J N; Kyle, J R; Olivares, R

The San Martin skarn deposit was formed by intrusion of the 46 Ma Cerro de la Gloria quartz monzonite stock into the Middle Cretaceous Cuesta del Cura limestone. Ensuing hydrothermal alteration produced a metamorphic aureole consisting of calc-silicate minerals and economic concentrations of Cu, Zn, and Ag. Ore bodies are centered around several large veins that roughly parallel the intrusive contact; mineralized endoskarn is locally developed. Cu and Ag decrease with increasing distance from the intrusive contact, and correlate inversely with Pb and Zn horizontally. Cu, Zn, Pb, and Fe increase with depth. Initial metasomatism produced andraditic garnet with lesser hedenbergitic clinopyroxene, along with substantial intercrystalline pore space which was subsequently filled with sulfides. Lower temperature calc-silicates include wollastonite, epidote, chlorite, and tremolite. Metallic minerals show a paragenetic sequence of early arsenopyrite, molybdenite, pyrrhotite, bornite, and chalcopyrite; intermediate sphalerite, chalcopyrite, tetrahedrite, and galena; and late native silver, pyrite, and stibnite. Fluorite, calcite, and minor quartz postdate prograde skarn development. Hydrothermal fluid circulation was controlled by pre-intrusion Laramide deformation and probably was enhanced by intrusion-related fracturing. The intrusive contact and the veins represent the major channels for fluid migration, with local controls affected by layers of impermeable shale and chert. Fluid inclusion data suggest that early mineralizing fluids were dominantly magmatic, with the meteoric component increasing with time.

• Research Organization: Univ. of Texas, Austin (USA)
• OSTI ID: 6273158
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
COPPER ORES
MINERALIZATION
HYDROTHERMAL SYSTEMS
ROCK-FLUID INTERACTIONS
MEXICO
SILVER ORES
ZINC ORES
CALCITE
CHALCOPYRITE
CHLORITE MINERALS
CRETACEOUS PERIOD
FLUORITE
GALENA
GEOTHERMAL FLUIDS
HYDROTHERMAL ALTERATION
INCLUSIONS
LIMESTONE
METAMORPHIC ROCKS
MINERALOGY
PLUTONIC ROCKS
PYRITE
QUARTZ
SPHALERITE
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER SULFIDES
DEVELOPING COUNTRIES
ENERGY SYSTEMS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GEOLOGIC AGES
GEOTHERMAL SYSTEMS
HALIDE MINERALS
HALIDES
HALOGEN COMPOUNDS
IGNEOUS ROCKS
IRON COMPOUNDS
IRON SULFIDES
LATIN AMERICA
LEAD COMPOUNDS
LEAD SULFIDES
MESOZOIC ERA
MINERALS
NORTH AMERICA
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SILICATE MINERALS
SILICON COMPOUNDS
SILICON OXIDES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
580400* - Geochemistry- (-1989)