Increasing concentration of subsurface brines with depth

Dickey, Parke A.

doi:10.1016/0009-2541(69)90055-2

Cited by 53 publications

(18 citation statements)

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“…During mineralization, near surface waters were presumably less saline than those at depth (Dickey, 1969). Hence there would be a tendency for dissolved salts to move upward and water molecules to move downward following the usual laws of chemical osmosis.…”

Section: Salt Sieving Phenomenamentioning

confidence: 98%

Zoning in the White Pine copper deposit, Ontonagon County, Michigan

Brown¹

1971

Economic Geology

114

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The top of the cupriferous zone in the lower Nonesuch Shale of Northern Michigan is characterized by an abrupt zonation of Cu-Fe sulfides which represents a chemical and mineralogic transition into the overlying barren pyritic shale. This narrow fringe forms a blanket-like surface which cross-cuts bedding at shallow angles. Although the ore horizons show strict stratigraphic controls, the actual upper limit of copper mineralization in the White Pine area occurs at various stratigraphic levels 20 to 50 feet above the base of the Nonesuch. A strong inverse correlation exists between the height of the fringe surface in the Nonesuch Shale and the amount of copper in the lowermost shale unit. In local areas along fracture zones, a very minor amount of copper has been channeled upward along some fracture zones producing local anomalous elevations in the fringe surface. The White Pine fault is clearly a post-ore structure which offsets the fringe surface.The ore minerals of the Cu-Fe transition show a step-by-step replacement of ironrich sulfides by paragenetically later copper-rich sulfides. The sequence in ascending order is chalcocite, djurleite, digenite, bornitc, chalcopyrite and pyrite. Abnormal concentrations of Cd and Pb occur immediately above the cupriferous zone. These observations suggest, as others have proposed, that the mineralization of the basal Nonesuch was accomplished by the introduction of copper from the underlying Copper Harbor Conglomerate soon after deposition of the Nonesuch Shale. Copper deposition in the sulfur-rich reducing environment of the Nonesuch occurred in large part by replacement of original pyrite along an upward advancing mineralization front (fringe). Metals more soluble than copper were apparently swept upward before the copper front.Simple mathematical models of infiltration and diffusion processes were designed to test the above hypothesis. Each model results in a mineralization period of about 106 years. It seems entirely possible that these mechanisms could account for the transport of copper into the early unconsolidated Nonesuch sediment. Salt sieving and gravity stratification phenomena may have assisted these basic processes. The ultimate source of copper is open to speculation, but may lie in primary magmatic contributions or extraction of metals from the thick volcanic-sedimentary pile of the Keweenawan basin.

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Section: Salt Sieving Phenomenamentioning

confidence: 98%

Zoning in the White Pine copper deposit, Ontonagon County, Michigan

Brown¹

1971

Economic Geology

114

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“…As is observed in many basins (e.g. Dickey 1969;Appold & Nunn 2005), salinity of aqueous fluids tends to increase with depth. Structural deformation in the shallow section could form migration pathways allowing the lower temperature, lower salinity fluids to migrate northwards (Fig.…”

Section: Hydrothermal Systemmentioning

confidence: 88%

What controls porosity in cherty fine-grained carbonate reservoir rocks? Impact of stratigraphy, unconformities, structural setting and hydrothermal fluid flow: Mississippian, SE Kansas

Ramaker

Goldstein

Franseen

et al. 2014

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The localization and heterogeneity of carbonate oil and gas reservoirs are commonly controlled by extensive diagenetic alteration. Mississippian (Osagean-Meramecian) strata in SE Kansas are investigated to determine structural, relative sea-level, diagenetic and depositional controls on stratigraphy, lithofacies distribution and reservoir character. This project shows how karst horizons and fractured zones can provide preferred conduits for hydrothermal porosity enhancement. Thus, enhanced porosity in karst horizons may have a late origin, with chemically aggressive hydrothermal fluids following preferred pathways of fluid flow.Lithofacies include echinoderm-rich bioclastic wacke-packstone, sponge-spicule-rich packstone, dolomitic bioclastic wackestone, argillaceous dolomite, tripolitic chert and chert breccia. Four cores are used to construct a 10 mile-long SW-NE-trending cross-section, showing three genetic units deposited on a mostly south-facing distally steepened ramp, with periods of upwelling.Paragenesis reveals that early and late dissolution enhances porosity in chert and carbonate facies. Fluid inclusion microthermometry from megaquartz and baroque dolomite reveals variable but increasing homogenization temperatures (70-160 8C) and increasing salinity through time. The best reservoirs may be controlled by depositional setting that led to large amounts of chert, alteration associated with subaerial exposure, and a hydrological and structural setting that led to enhanced hydrothermal fluid flow for later dissolution.

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“…This is a typical mechanism of dedolomitization in carbonate rocks (Back and Hanshaw, 1970;Hanshaw and Back, 1979;Back et al, 1983;Busby et al, 1990;Plummer et al, 1990). (Dickey, 1969). between the injection and production wells.…”

Section: Future Plansmentioning

confidence: 96%

Anisotropy and spatial variation of relative permeability and lithologic character of Tensleep Sandstone reservoirs in the Bighorn and Wind River Basins, Wyoming. Annual report, October 1, 1994-- September 30, 1995

Dunn¹

1996

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Increasing concentration of subsurface brines with depth

Cited by 53 publications

References 1 publication

Zoning in the White Pine copper deposit, Ontonagon County, Michigan

Zoning in the White Pine copper deposit, Ontonagon County, Michigan

What controls porosity in cherty fine-grained carbonate reservoir rocks? Impact of stratigraphy, unconformities, structural setting and hydrothermal fluid flow: Mississippian, SE Kansas

Anisotropy and spatial variation of relative permeability and lithologic character of Tensleep Sandstone reservoirs in the Bighorn and Wind River Basins, Wyoming. Annual report, October 1, 1994-- September 30, 1995

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