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.
| 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.date.updated | 2016-07-15T13:21:05Z | |
| 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.identifier | http://dx.doi.org/10.1016/j.sedgeo.2006.06.008 | |
| 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.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.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 |
| dc.identifier.uri | http://hdl.handle.net/11427/20386 | |
| dc.identifier.uri | http://www.sciencedirect.com/science/article/pii/S0037073806001758 | |
| 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.language | eng | en_ZA |
| dc.publisher | Elsevier | en_ZA |
| dc.publisher.department | Department of Geological Sciences | en_ZA |
| dc.publisher.faculty | Faculty of Science | en_ZA |
| dc.publisher.institution | University of Cape Town | |
| 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 |
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Article | en_ZA |