Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Genesis of Mississippi Valley-Type deposits of the southernmost Appalachians: The black shale connection

Conference · · Geological Society of America, Abstracts with Programs; (United States)
OSTI ID:6368759
;  [1]
  1. Auburn Univ., AL (United States). Dept. of Geology

Mississippi Valley-Type (MVT) mineralization near the southern terminus of the Appalachians occurs in karstified Cambro-Ordovician Knox Group carbonates that lie beneath the Middle Ordovician Athens Shale. The Athens Shale is the organic-rich deep basinal facies of a foreland depocenter that formed at the onset of Taconic orogenesis and was subsequently deformed during multiple Appalachian orogenic events. Molybdenum, cobalt, and nickel concentrations in the Athens Shale are enriched relative to average shales and are comparable to typical black shales. MVT mineralization in northwest Georgia locally contains > 2,000 ppm Mo, > 500 ppm Ni, and > 30 ppm Co., concentrations which are anomalous compared to typical MVT deposits elsewhere. Given the stratigraphic proximity and geochemical similarities of the Athens Shale and the MVT mineralization, along with the presence of hydrothermal pyrite-quartz-calcite-barite-sphalerite veinlets in the Athens, the authors propose that the Athens Shale was the source of ore-forming solutions. Northwest-directed middle Paleozoic compressional deformation is interpreted to have focused Athens-derived fluids into the paleoaquifer at the top of the Knox Group. Although the significance of basin dewatering in the genesis of MVT deposits is generally accepted, direct hydrologic connection between a specific MVT deposit and source formation has not been recognized previously.

OSTI ID:
6368759
Report Number(s):
CONF-9304188--
Journal Information:
Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:4; ISSN GAAPBC; ISSN 0016-7592
Country of Publication:
United States
Language:
English