Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa.

 

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dc.contributor.author Herbert, C T
dc.contributor.author Compton, J S
dc.date.accessioned 2016-07-15T13:23:23Z
dc.date.available 2016-07-15T13:23:23Z
dc.date.issued 2007
dc.identifier http://dx.doi.org/10.1016/j.sedgeo.2006.06.008
dc.identifier.citation Herbert, C. T., & Compton, J. S. (2007). Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa. Sedimentary Geology, 194(3), 263-277. en_ZA
dc.identifier.issn 0037-0738 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/20386
dc.identifier.uri http://www.sciencedirect.com/science/article/pii/S0037073806001758
dc.description.abstract The upper Dwyka and lower Ecca Groups in the Karoo Basin of South Africa document the climatic and palaeoenvironmental changes associated with the final Permo-Carboniferous deglaciation of the Gondwana supercontinent. The depositional environments of these groups have, until recently, been interpreted on the basis of sedimentological and palaeontological evidence. Here we use the geochemistry of early diagenetic concretions – septarian calcite concretions from the upper Dwyka Group and phosphatic chert concretions and beds from the lower Ecca Group – to infer the depositional environment of these rocks in the southwestern Karoo Basin. δ18O values (7.8 to 8.9‰ SMOW) suggest that the calcite concretions precipitated from a mixture of meteoric and glacial melt waters rather than Permian seawater. δ 13C values (−15 to −3‰ PDB) indicate that the carbon was derived from a mixture of craton-derived calcareous material and organic matter, bacterially degraded in the lower sulphatereduction to upper methanogenesis zones during early burial diagenesis. The rare-earth element (REE) patterns, Sr concentrations and 87Sr/86Sr ratios (0.716–0.737) significantly greater than Permian seawater (0.708), together also support the interpretation that calcite and phosphatic concretions formed in glacial, fresh water sediments. en_ZA
dc.language eng en_ZA
dc.publisher Elsevier en_ZA
dc.source Sedimentary Geology en_ZA
dc.source.uri http://www.sciencedirect.com/science/journal/00370738/194/3
dc.subject.other Permo-Carboniferous
dc.subject.other Ice age
dc.subject.other Rare earth elements
dc.subject.other Stable isotopes
dc.subject.other Sr isotopes
dc.subject.other Gondwana
dc.title Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa. en_ZA
dc.type Journal Article en_ZA
dc.date.updated 2016-07-15T13:21:05Z
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Geological Sciences en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Herbert, C. T., & Compton, J. S. (2007). Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa. <i>Sedimentary Geology</i>, http://hdl.handle.net/11427/20386 en_ZA
dc.identifier.chicagocitation Herbert, C T, and J S Compton "Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa." <i>Sedimentary Geology</i> (2007) http://hdl.handle.net/11427/20386 en_ZA
dc.identifier.vancouvercitation Herbert CT, Compton JS. Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa. Sedimentary Geology. 2007; http://hdl.handle.net/11427/20386. en_ZA
dc.identifier.ris TY - Journal Article AU - Herbert, C T AU - Compton, J S AB - The upper Dwyka and lower Ecca Groups in the Karoo Basin of South Africa document the climatic and palaeoenvironmental changes associated with the final Permo-Carboniferous deglaciation of the Gondwana supercontinent. The depositional environments of these groups have, until recently, been interpreted on the basis of sedimentological and palaeontological evidence. Here we use the geochemistry of early diagenetic concretions – septarian calcite concretions from the upper Dwyka Group and phosphatic chert concretions and beds from the lower Ecca Group – to infer the depositional environment of these rocks in the southwestern Karoo Basin. δ18O values (7.8 to 8.9‰ SMOW) suggest that the calcite concretions precipitated from a mixture of meteoric and glacial melt waters rather than Permian seawater. δ 13C values (−15 to −3‰ PDB) indicate that the carbon was derived from a mixture of craton-derived calcareous material and organic matter, bacterially degraded in the lower sulphatereduction to upper methanogenesis zones during early burial diagenesis. The rare-earth element (REE) patterns, Sr concentrations and 87Sr/86Sr ratios (0.716–0.737) significantly greater than Permian seawater (0.708), together also support the interpretation that calcite and phosphatic concretions formed in glacial, fresh water sediments. DA - 2007 DB - OpenUCT DP - University of Cape Town J1 - Sedimentary Geology LK - https://open.uct.ac.za PB - University of Cape Town PY - 2007 SM - 0037-0738 T1 - Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa TI - Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa UR - http://hdl.handle.net/11427/20386 ER - en_ZA


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