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METALS IN PENNSYLVANIAN BLACK SHALES FROM ORE FLUIDS NOT FROM SEAWATER

Metals in Pennsylvanian black shales from ore fluids not sea water. METALS IN PENNSYLVANIAN BLACK SHALES FROM ORE FLUIDS NOT FROM SEAWATER. Illinois . sphalerite in Stark shale, N MO. rmc. coveneyr@umkc.edu. Zinc in Pennsylvanian black shales, Kansas City.

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METALS IN PENNSYLVANIAN BLACK SHALES FROM ORE FLUIDS NOT FROM SEAWATER

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  1. Metals in Pennsylvanian black shales from ore fluids not sea water METALS IN PENNSYLVANIAN BLACK SHALES FROM ORE FLUIDS NOT FROM SEAWATER Illinois sphalerite in Stark shale, N MO rmc coveneyr@umkc.edu

  2. Zinc in Pennsylvanian black shales, Kansas City The Hushpuckney black shale, one of several metal-rich beds in Kansas City, contains >0.2 wt % Zn (>2000 ppm). Coveney 1979 Economic Geology

  3. Typical metal values for metalliferous Pennsylvanian black shales, central USA from Schultz & Coveney, 1991, Chemical Geology

  4. Metalliferous Pennsylvanian black shales contain abundant Mo.

  5. Shale Basins and MVT Ore Districts UMV Illinois Basin Forest City Basin Salina Basin Mo Pb Cherokee Basin Tri-State Arkoma Basin

  6. Hydrothermal dolomite + crystalline kaolinite** or dickite(Schroeder & Hayes 1968; Keller 1988) Illinois Basin Forest City Basin Salina Basin Mo Pb Cherokee Basin Tri-State Arkoma Basin

  7. 1 cm Salina Basin Sphalerite in Mecca Qu. Shale equiv., central MO

  8. Sphalerite in Pennsylvanian black shales from Coveney 1979 Economic Geology from Coveney 1984 C.R. IX ICC Hushpuckney Shale Mbr, Kansas City MO Mecca Quarry Shale Mbr, Parke Co. IN

  9. Sphalerite cleat in Stark Shale sph

  10. from JC Cobb, U IL dissertation, 1981 MVT mineralization occurs in other beds as well. sph. cleat in coal sph 1 cm Sphalerite in coal

  11. MVT minerals, sphalerite and kaolinite in Pennsylvanian limestone. Stark KS kaolinite sphal Bethany Falls limestone mbr., Stark, KS

  12. hydrothermal passageways hydrothermal passageways Hydrothermal venting through root casts or burrows Bethany Falls Limestone, North Farlinville KS Bethany Falls Limestone North Farlinville KS

  13. sph kaolinite back

  14. Kaolinite in hydrothermally corroded limestone U.S. Hwy 36 Livingston Co MO

  15. Keller’s SEMof sugary white kaolinite in Winterset limestone, Kansas City MO from W.D. Keller, 1988, Clays and Clay Minerals 36,154

  16. Mineralized tubes with dolomite, calcite, sphalerite and kaolinite Mineralized tubes with hydrothermal dolomite, calcite, sphalerite and crystalline kaolinite Bethany Falls Limestone, Mound City KS

  17. Dolomite veinlets I-470 Kansas City ferroan dolomite + tr sphal.

  18. MVT minerals in Pennsylvanian limestone, Kansas City MO barite ferroan dolomite wall of Central United Methodist Church

  19. A mid-Mississippian to mid-Pennylvanian DRM or CRM paleopole for Stark Shale fits with syngenetic magnetism Kawasaki et al. 2007 Geophysical Journal International

  20. Mineralization of black shales has been attributed to sea water* but this conclusion depends on log-log plots that minimize deviations from the central trend. Log-Log plots Mebl sh vs. Mes.w. *Brongersma-Sanders 1966 Geol. Rundschau; Heckel 1977 AAPG Bulletin; Holland 1979 Economic Geology from HD Holland Econ. Geol. 1979

  21. x for molybdenum in shales and muds Mecca Quarry shale 1500 ppm Carioca Trench 150 Black Sea 77 Kau Bay, Indonesia 100 average black shale 100 average shale 3 Turekian and Wedepohl, 1961; Holland 1979, 1984; Calvert 1990; Middelburg 1990; Dean et al. 1999; Zheng et al. 2000 GCA;

  22. Th for primary fluid inclusions in sphalerite; calcite dates (yellow) 251 Ma 136 Ma 66 Ma 39 Ma after Coveney, Goebel & Ragan 1987 EconomicGeology

  23. Chronology for MVT ores, petroleum migration, regional tectonics, and black shales from Coveney et al 2000, Geology

  24. Sources of metals for shales X X X X X

  25. Key Facts • Zinc, Mo and other metals are widespread in Pennsylvanian shales. • MVT minerals are ubiquitous throughout the central US craton in Paleozoic strata. • Hydrothermal sphalerite occurs in shales, limestones, and coals of the US craton. • Ores formed during the late Paleozoic. • Hydrothermal fluids traversed the region for long periods.

  26. Zn in shale from sea water???? • No. • More likely the Zn for sphalerite in the shales came from the same source as the Zn in the MVT ores, having been transported by regional flow of basinal brines.

  27. Hydraulic head ca. 300-250 Ma Ancestral Rocky Mtns Appalachians Ouachita Mtns

  28. A chronology for mineralization from basinal brines in the U.S. Midcontinent • Early venting of hydrothermal fluids to Pennsylvanian seas and sediments with deposition of trace MVT ore and gangue minerals in accumulating Paleozoic sediments and rocks. • Shales, mainly gray, sealed hydrothermal systems. • Continued hydrothermal activity plugged minor passageways and led to formation of major ore deposits. • Dates on calcite gangue show that sporadic migration of basinal brines continued for >100 million years. • Even today basinal brines from the Rockies reach central MO. • Hydrothermal basinal brines were the sources of metals for black shales.

  29. Metals in Midwestern Pennsylvanian shales did not come from sea water. Thank you!

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