Alteration and fluid flow around a sulfide-carbonate-quartz vein, Lucky Friday mine, Northern Idaho

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

OSTI ID:6596707

Gitlin, E C

Wall rocks at the Lucky Friday mine, Coeur d'Alene district, Idaho, contain a >500m wide zone about a steeply dipping Pb-Zn-Ag vein. This zone has experienced local conditions distinct from the regional metamorphism of the quartzite + argillite host rock. Within the district, the host rock (Precambrian Revett Formation) has undergone low grade metamorphism and contains varying proportions of quartz, phengitic muscovite, detrital alkali feldspar, magnetite, hematite, ilmenite, rutile, zircon, tourmaline, +/- calcite, +/- ankeritic dolomite. In contrast, the Lucky Friday wall rocks lack feldspar and Fe-bearing oxides, and contain Fe-poor muscovite and up to 40% carbonate: siderite, ankerite, and/or calcite. A comparison of district-wide Revett rocks with Lucky Friday wall rocks suggests that the wall rocks have undergone localized dephengitization with concomitant Fe-enrichment in the carbonates and Fe-depletion of the oxides. Pertinent metamorphic reactions consume CO/sub 2/ and liberate H/sub 2/O. Fluid inclusions from the vein and wall rock stringers have homogenization temperatures from approx. =200/sup 0/ to <375/sup 0/C, but they define no temperature gradient. With few exceptions, compositions of the carbonates are identical throughout the altered wall rock. These observations suggest that the carbonate subzone contacts are not isograds but isofluxes: the loci of equivalent fluid/reactant mineral ratio. The disposition of isofluxes around a dominant fluid channelway, i.e. the vein, affords an opportunity to interpret fluid flow pathways during low temperatures metamorphism.

• Research Organization: Univ. of Washington, Seattle (USA)
• OSTI ID: 6596707
• 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
ARGILLITE
HYDROTHERMAL ALTERATION
ROCK-FLUID INTERACTIONS
IDAHO
QUARTZITES
LEAD ORES
MINERALOGY
PETROGENESIS
SILVER ORES
ZINC ORES
CARBONATE MINERALS
FELDSPARS
GEOLOGIC FORMATIONS
METAMORPHISM
MICA
PRECAMBRIAN ERA
QUARTZ
SULFIDE MINERALS
CHALCOGENIDES
FEDERAL REGION X
GEOLOGIC AGES
METAMORPHIC ROCKS
MINERALS
NORTH AMERICA
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SHALES
SILICON COMPOUNDS
SILICON OXIDES
USA
580300* - Mineralogy
Petrology
&amp; Rock Mechanics- (-1989)