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

Abstract

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 developedmore » during the Alleghenian Orogeny.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Geological Survey, Reston, VA (USA)
OSTI Identifier:
6461299
Report Number(s):
CONF-8510489-
Journal ID: CODEN: GAAPB
Resource Type:
Conference
Journal Name:
Geol. Soc. Am., Abstr. Programs; (United States)
Additional Journal Information:
Journal Volume: 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
Country of Publication:
United States
Language:
English
Subject:
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)

Citation Formats

Hearn, P P, Sutter, J F, Kunk, M J, and Belkin, H E. Evidence for Alleghenian brine migration in the central and southern Appalachians: implications for Mississippi valley-type sulfide mineralization. United States: N. p., 1985. Web.
Hearn, P P, Sutter, J F, Kunk, M J, & Belkin, H E. Evidence for Alleghenian brine migration in the central and southern Appalachians: implications for Mississippi valley-type sulfide mineralization. United States.
Hearn, P P, Sutter, J F, Kunk, M J, and Belkin, H E. 1985. "Evidence for Alleghenian brine migration in the central and southern Appalachians: implications for Mississippi valley-type sulfide mineralization". United States.
@article{osti_6461299,
title = {Evidence for Alleghenian brine migration in the central and southern Appalachians: implications for Mississippi valley-type sulfide mineralization},
author = {Hearn, P P and Sutter, J F and Kunk, M J and Belkin, H E},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/6461299}, journal = {Geol. Soc. Am., Abstr. Programs; (United States)},
number = ,
volume = 17,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1985},
month = {Tue Jan 01 00:00:00 EST 1985}
}

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