Evidence for Alleghenian brine migration in the central and southern Appalachians: implications for Mississippi valley-type sulfide mineralization

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

OSTI ID:6461299

Hearn, P P; Sutter, J F; Kunk, M J; Belkin, H E

Authigenic K-feldspar has been found in rocks near Mississippi Valley-Type (MVT) sulfide mineralization in lower Paleozoic carbonate rocks of Pennsylvania, Maryland, Virginia, and Tennessee. Synthetic /sup 40/Ar//sup 39/Ar age spectra for the authigenic K-feldspar yield Carboniferous ages. Mass balance calculations indicate that the formation of the K-feldspar involved the flux of multiple pore volumes of fluid through the rocks. Estimates of vapor-liquid ratios and microthermometric homogenization temperatures of primary fluid inclusions in K-feldspar overgrowths, the presence of halite daughter crystals in some associated carbonate-hosted inclusions, and low whole-rock Cl/Br ratios indicate the K-feldspar formed by the interaction of connate brines with siliciclastic debris at temperatures between 100/sup 0/ and 200/sup 0/C. The common occurrence of feldspathized rocks stratigraphically below mineralized zones and the similarity of primary fluid inclusions in K-feldspar overgrowths to those observed in ore and qanque minerals suggest the authigenic K-feldspar and mineralization are coeval. The Carboniferous age suggested by /sup 40/Ar//sup 39/Ar age spectra is consistent with estimates based on (1) paleomagnetic studies and (2) analyses of sphalerite deformation fabrics. Accordingly, the authors suggest that MVT sulfide deposits in the central and southern Appalachians were emplaced by the migration of heated connate brines along structural pathways developed during the Alleghenian Orogeny.

• Research Organization: Geological Survey, Reston, VA (USA)
• OSTI ID: 6461299
• 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
CARBONATE ROCKS
HYDROTHERMAL ALTERATION
SULFIDE MINERALS
MARYLAND
PENNSYLVANIA
HYDROTHERMAL SYNTHESIS
MINERALIZATION
TENNESSEE
VIRGINIA
APPALACHIAN MOUNTAINS
BRINES
CHEMICAL REACTIONS
FELDSPARS
GEOCHEMISTRY
INCLUSIONS
ISOTOPE DATING
MASS BALANCE
MIGRATION
OROGENESIS
PALEOMAGNETISM
PALEOZOIC ERA
PETROGENESIS
AGE ESTIMATION
CHEMISTRY
FEDERAL REGION III
FEDERAL REGION IV
GEOLOGIC AGES
MAGNETISM
MINERALS
MOUNTAINS
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
SYNTHESIS
USA
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)
580400 - Geochemistry- (-1989)