Fluid inclusion and isotopic studies of the galena mine, Coeur d'Alene district, ID

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:5892647

Yates, M G; Ripley, E M

The Ag-Cu-Pb ores of the Galena Mine in the Coeur d'Alene District of Northern Idaho are mesothermal, vein-type ores, localized along steeply dipping fractures in Proterozoic, Belt Supergroup rocks. The veins are primarily filled with siderite with lesser amounts of quartz, tetrahedrite (td), chalcopyrite (cp), galena (gn), pyrite (py), and arseno-pyrite (asp). Siderite and arsenopyrite deposition predates that of main-stage td, cp, gn, py, and quartz. Oxygen isotopic analyses of quartz show values ranging from 9.8 /per thousand/ to 18.0 /per thousand/, averaging 14.5 /per thousand/. The /delta//sup 18/O values of the Revett Quartzite country rock range from 12.2 to 13.8 /per thousands/. Calculated /delta//sup 18/O/sub H/sub 2/O/ at 325/degree/C is approximately 8.5 /per thousand/, suggesting exchange of isotopically light meteoric water with isotopically heavy country rocks. Analyses of carbon and oxygen isotopes in siderite are highly variable. The /delta//sup 13/C values vary from -8.3 to -4.4, as /delta//sup 18/O varies from 11.7 to 19.0 /per thousand/ respectively. These analyses describe a simple curve, concave to the /delta//sup 13/C axis. This trend may result from deposition from a constant carbon and oxygen reservoir of -5.6 /per thousand/ and 9.3 /per thousand/, respectively, with varying temperature. Fluid inclusions from quartz vugs contain constant proportions of liquid H/sub 2/O, liquid CO/sub 2/, and vapor. The inclusions rupture before homogenizing at temperatures around 325/degree/C. Freezing temperatures average -7.5/degree/C, indicating a salinity of /approx/ 11 wt. percent NaCl Equiv. CO/sub 2/ comprises a mole fraction of .05 to .1 of extracted fluids. Analysis of water extracted from the inclusions show /delta/D to vary from -110 to -144 /per thousand/, strongly suggesting a meteoric water origin of the mineralizing fluid.

• Research Organization: Indiana Univ., Bloomington (USA)
• OSTI ID: 5892647
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
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58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
580400 -- Geochemistry-- (-1989)
CARBON ISOTOPES
CHALCOGENIDES
CHALCOPYRITE
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMISTRY
COPPER COMPOUNDS
COPPER ORES
COPPER SULFIDES
ENERGY SYSTEMS
FEDERAL REGION X
GALENA
GEOCHEMISTRY
GEOTHERMAL SYSTEMS
GROUND WATER
HYDROGEN COMPOUNDS
HYDROTHERMAL SYSTEMS
IDAHO
INCLUSIONS
IRON COMPOUNDS
IRON SULFIDES
ISOTOPE RATIO
ISOTOPES
LEAD COMPOUNDS
LEAD ORES
LEAD SULFIDES
MINERALIZATION
MINERALOGY
MINERALS
NORTH AMERICA
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PETROGENESIS
PYRITE
QUANTITATIVE CHEMICAL ANALYSIS
QUARTZ
ROCK-FLUID INTERACTIONS
SALINITY
SILICON COMPOUNDS
SILICON OXIDES
SILVER ORES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
WATER