Mississippi valley deposits

Zinc. Zinc deposits in the United States extend from Maine through the Appalachian Mountains, and west through the Mississippi Valley into the Rocky Mountain states. U.S. reserves are estimated to be 27 x t Zn (108). World reserves and resources are 135 and 110 x 10 t, respectively. The... 

Anderson, G. M. and G. Garven, 1987, Sulfate-sulfide-carbonate associations in Mississippi Valley-type lead-zinc deposits. Economic Geology 82,482 488. 

Sphalerite from the till displays a range of 534S values from-14.1 to -6.0 per mil with a mean value of -9.0 per mil. These low values are interpreted to be the result of bacterial reduction of coeval seawater sulphate. These values are different than those reported for Mississippi Valley-type deposits in the northern and southern Cordillera, which are dominantly much heavier (Fig. 4). Sulphur isotope values... 

Nelson, J., Paradis, S., Christensen, J. Gabites, J. 2002. Canadian Cordilleran Mississippi Valley-type deposits A case for Devonian-Mississippian back-arc hydrothermal origin. Economic Geology, 97, 1013-1036. 

Chlorine is the major anion in surface- and mantle-derived fluids. It is the most abundant anion in hydrothermal solutions and is the dominant metal complexing agent in ore forming environments (Banks et al. 2000). Despite its variable occurrence, chlorine isotope variations in natural waters conunonly are small and close to the chlorine isotope composition of the ocean. This is also true for chlorine from fluid inclusions in hydrothermal minerals which indicate no significant differences between different types of ore deposits such as Mississippi-Valley and Porphyry Copper type deposits (Eastoe et al. 1989 Eastoe and Guilbert 1992). 

The Mississippi Valley Type (MVT) deposits are epigenetic Zn-Pb deposits which mainly occnr in carbonates from continental settings (Ohmoto 1986). 

Deposits in the Mississippi Valley, U.S.A., Trans. Sect. B., Inst. Mining Metallurgy (1969) 78, B148-B160. 

In the bituminous coals of the US Illinois and Appalachian basins, arsenic primarily occurs in pyrite. The arsenian pyrite probably originated from subsurface fluids that existed about 270 million years ago during the formation of the Ouachita and Appalachian mountains (Goldhaber, Lee and Hatch, 2003). The arsenic-bearing fluids in the midcontinent Illinois Basin were primarily brines derived from surrounding sedimentary basins that were also responsible for the formation of the Mississippi Valley lead-zinc deposits. In contrast, the fluids that were responsible for the arsenian pyrites in the Appalachians (especially in the coals of the Warrior Basin of Alabama) were metamorphic and not as saline as those in the midcontinent (Goldhaber, Lee and Hatch, 2003). 

Basinal Brines as a Source of Sulfur in High-Sulfur Coals. Sulfide minerals, such as pyrite and sphalerite, in coal seams may be deposited from basinal hydrothermal fluids. The occurrence of epigenetic sphalerite in Illinois Basin coals has been described by Hatch et al. (119) and Cobb (120). Whelan et al. (121) studied the isotopic composition of pyrite and sphalerite in coal beds from the Illinois Basin and the Forest City Basin, and suggested that some of the coals were affected by Mississippi Valley-type hydrothermal solutions. 

Sedimentary formation waters have long been invoked as ore-forming fluids in a number of distinctly different geologic settings. Although ore deposit classification schemes vary, the following have been genetically associated with basinal fluids (i) Mississippi-Valley-type lead, zinc, copper, barium, and fluoride deposits (ii) shale-hosted lead, zinc, and barium deposits (iii) rift-basin and redbed copper deposits ... 

Kesler S. E., Martini A. M., Appold M. S., Walter L. M., Huston T. J., and Furman F. C. (1996) Na-Cl-Br systematics of fluid inclusions from Mississippi Valley-type deposits, Appalachian Basin constraints on solute origin and migration paths. Geochim. Cosmochim. Acta 60, 225-233. 

Sverjensky D. A. (1986) Genesis of Mississippi Valley-type lead zinc deposits. Ann. Rev. Earth. Planet. Sci. 14, 177-199. 

Mississippi Valley type Lead Zinc deposits Pine Point, Northwest Territories, Canada Gravity or compaction flow of brines from deep sedimentary basins Leaching from sedimentary source rocks, transport, and deposition due to declining temperatures and and possibly changing Eh PH... 

A symposium devoted to the Mississippi Valley type ore deposits is the subject of Economic Geology, Monograph No. 3 (J.S. Brown, Ed., 1967). 

Barton, P.B., Jr., 1967. Possible role of organic matter in the precipitation of the Mississippi Valley ores. In J.S. Brown (Editor), Genesis of Statiform Lead-Zinc-Barite-Fluorite Deposits (Mississippi Valley Type Deposits). Econ. Geol., Monograph 3, pp. 363-369. 

Beales, F.W., 1975. Precipitation mechanisms of Mississippi Valley-type ore deposits. Econ. Geol., 70 943—948. 

Figure 2. Locations and ages of major Mississippi Valley-type (MVT) ore deposit districts of the mid-continental United States. The ages are taken from Brannon et al.( 996) Chesley et aI.(J994) Symons et at. (1997).

Anderson, G. M., 1983, Some geochemical aspects of sulfide precipitation in carbonate rocks in International conference on Mississippi Valley Type lead-zinc deposits, Rolla,... 

Barnes, H. L, 1983, Ore-depositing reactions in Mississippi Valley-type deposits in Kisvarsanyi, G., Grant, S. K., Pratt, W. P., and Koenig, J. W., eds., International conference on Mississippi VaUey-type lead-zinc deposits proceedings volume RoUa, Missouri, United States, University ofMissouri Press, p. 77-85. 

Brannon, J. C., Podosek, F. A., and Cole, S. C., 1997, Radiometric dating of Mississippi Valley-type ore deposits in Sangster, D. F., ed.. Carbonate-hosted lead-zinc deposits Special Publication - Society of Economic Geologists, p. 536-545. 

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