Oxygen and hydrogen isotope geochemistry of the Coeur d'Alene mining district, Idaho

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6747660

Constantopoulos, J T

Eighty-five oxygen isotope analyses of vein quartz ere obtained along with 12 analyses of Belt rocks and three analyses of igneous rocks. Sixteen D/H analyses were obtained from quartz inclusion fluids. Oxygen extractions were performed using standard techniques with ClF{sub 3}. Water for the D/H analyses was obtained by crushing. Results are reported in standard {delta} notation relative to SMOW. The {delta}{sup 18}O{sub QTZ} values range from +9.48 to +18.04{per thousand} and approximate a normal distribution. Contoured mean {delta}{sup 18}O{sub QTZ} values for each mine reveal isotopic lows offset by about 20 km across the Osburn fault. Mean {delta}{sup 18}O{sub QTZ} values for each of the three productive intervals of the Belt range from 14.93{per thousand} (middle Prichard) to 14.45{per thousand} (Revett-St. Regis). Twenty-six analyses of vein quartz from the Star-Morning mine reveal a decrease in {delta}{sup 18}O{sub QTZ} toward deeper mine levels. Hydrogen isotope compositions of quartz inclusion fluids range from +43 to -105{per thousand}. Positive values are attributed to H{sub 2}O-CH{sub 4} exchange. Mean {delta}D values for the middle Prichard and Prichard-Burke are +25{per thousand} and -15{per thousand}, respectively. The presence of positive {delta}D values and reduced hydrocarbon species in fluid inclusions from these intervals suggests relatively reduced ore fluids derived from formation waters in the Pritchard. The mean {delta}D for the Revett-St. Regis is -68{per thousand}. Inclusions in quartz from these veins contain CO{sub 2}, suggesting the ore fluids are a mixture of formation waters and oxidized meteoric waters. The {delta}{sup 18}O values of regionally metamorphosed Belt rocks range from +12.35 to +16.81{per thousand}. The values of contact metamorphosed Belt rocks and igneous rocks range from +7.15 to 8.9{per thousand}.

• Research Organization: Idaho Univ., Moscow, ID (USA)
• OSTI ID: 6747660
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALKANES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
DEUTERIUM
DISTRIBUTION
EVEN-EVEN NUCLEI
FEDERAL REGION X
FLUIDS
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GROUND WATER
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
IDAHO
IGNEOUS ROCKS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
METAMORPHISM
METEORIC WATER
METHANE
MINERALIZATION
MINERALS
MINES
NORTH AMERICA
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORIGIN
OXIDE MINERALS
OXIDES
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
QUARTZ
RESERVOIR FLUIDS
ROCKS
SILICON COMPOUNDS
SILICON OXIDES
STABLE ISOTOPES
UNDERGROUND FACILITIES
USA
WATER