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Title: Formation of sulfide-calcite veinlets in the Kupferschiefer Cu-Ag deposits in Poland by natural hydrofracturing during basin subsidence

Abstract

Calcite and copper-(iron) sulfide veinlets in the Kupferschiefer ore deposits in southwestern Poland display many characteristics of antitaxial veinlets, including trails of wall-rock shards from wall to wall. Cross-cutting relationships demonstrate a change from sulfate to sulfide chemical stability and an evolution of stress orientation during ore-formation. Bedding-plane sulfate veinlets and later bedding-plane sulfide veinlets are superseded by vertical sulfide veinlets, suggesting tectonic extension during ore-formation. Thin bedding-plane calcite-(sulfide) veinlets record a return to pre-ore stress conditions after ore formation ceased. The vertical veinlets are thin and lens-shaped, typically 1-3 mm thick, 30-35 cm high, and 50-70 cm long, with orientations similar to Kimmerian-age (Triassic-Jurassic) directions. Sulfide replacement lenses cut across and are cut by vertical veinlets, suggesting contemporaneous formation after lithification. A mid-Triassic paleomagnetic age and cross-cutting Alpine-age faults and dikes suggest that the veinlets and other mineralization formed during rapid subsidence in the Triassic, and not during Alpine-age uplift. A genetic model is proposed whereby the fractures originated by natural hydrofracturing caused by (1) aquathermal pressuring and (2) generation of water, CO/sub 2/, and CH/sub 4/ from the coal organic matter in the Kupferschiefer, aided by over-pressured pore fluid. It is inferred that the mineralization was accompanied bymore » natural-gas generation and by opening of the Tethys. 61 references.« less

Authors:
Publication Date:
Research Org.:
Univ. of Michigan, Ann Arbor
OSTI Identifier:
5543748
Resource Type:
Journal Article
Journal Name:
J. Geol.; (United States)
Additional Journal Information:
Journal Volume: 95:4
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 03 NATURAL GAS; COAL DEPOSITS; GEOCHEMISTRY; GEOLOGIC HISTORY; NATURAL GAS DEPOSITS; POLAND; CALCITE; CARBON DIOXIDE; COPPER ORES; DIKES; FRACTURING; GEOLOGIC FAULTS; GEOLOGIC FRACTURES; GEOLOGIC MODELS; METHANE; MINERALIZATION; ORIGIN; RESERVOIR FLUIDS; SILVER ORES; SULFIDES; ALKALINE EARTH METAL COMPOUNDS; ALKANES; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CARBON COMPOUNDS; CARBON OXIDES; CARBONATE MINERALS; CARBONATES; CHALCOGENIDES; CHEMISTRY; COMMINUTION; DEVELOPING COUNTRIES; EASTERN EUROPE; EUROPE; FLUIDS; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; HYDROCARBONS; MINERAL RESOURCES; MINERALS; ORES; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; RESOURCES; SULFUR COMPOUNDS; 011000* - Coal, Lignite, & Peat- Reserves, Geology, & Exploration; 030900 - Natural Gas- Artificial Stimulation, Plowshare- (-1989)

Citation Formats

Jowett, E C. Formation of sulfide-calcite veinlets in the Kupferschiefer Cu-Ag deposits in Poland by natural hydrofracturing during basin subsidence. United States: N. p., 1987. Web. doi:10.1086/629146.
Jowett, E C. Formation of sulfide-calcite veinlets in the Kupferschiefer Cu-Ag deposits in Poland by natural hydrofracturing during basin subsidence. United States. https://doi.org/10.1086/629146
Jowett, E C. Wed . "Formation of sulfide-calcite veinlets in the Kupferschiefer Cu-Ag deposits in Poland by natural hydrofracturing during basin subsidence". United States. https://doi.org/10.1086/629146.
@article{osti_5543748,
title = {Formation of sulfide-calcite veinlets in the Kupferschiefer Cu-Ag deposits in Poland by natural hydrofracturing during basin subsidence},
author = {Jowett, E C},
abstractNote = {Calcite and copper-(iron) sulfide veinlets in the Kupferschiefer ore deposits in southwestern Poland display many characteristics of antitaxial veinlets, including trails of wall-rock shards from wall to wall. Cross-cutting relationships demonstrate a change from sulfate to sulfide chemical stability and an evolution of stress orientation during ore-formation. Bedding-plane sulfate veinlets and later bedding-plane sulfide veinlets are superseded by vertical sulfide veinlets, suggesting tectonic extension during ore-formation. Thin bedding-plane calcite-(sulfide) veinlets record a return to pre-ore stress conditions after ore formation ceased. The vertical veinlets are thin and lens-shaped, typically 1-3 mm thick, 30-35 cm high, and 50-70 cm long, with orientations similar to Kimmerian-age (Triassic-Jurassic) directions. Sulfide replacement lenses cut across and are cut by vertical veinlets, suggesting contemporaneous formation after lithification. A mid-Triassic paleomagnetic age and cross-cutting Alpine-age faults and dikes suggest that the veinlets and other mineralization formed during rapid subsidence in the Triassic, and not during Alpine-age uplift. A genetic model is proposed whereby the fractures originated by natural hydrofracturing caused by (1) aquathermal pressuring and (2) generation of water, CO/sub 2/, and CH/sub 4/ from the coal organic matter in the Kupferschiefer, aided by over-pressured pore fluid. It is inferred that the mineralization was accompanied by natural-gas generation and by opening of the Tethys. 61 references.},
doi = {10.1086/629146},
url = {https://www.osti.gov/biblio/5543748}, journal = {J. Geol.; (United States)},
number = ,
volume = 95:4,
place = {United States},
year = {1987},
month = {7}
}