Cyclic sedimentation at sites 745 and 746
The upper Miocene to Pleistocene sediments recovered at ODP Sites 745 and 746 in the Australian-Antarctic Basin are characterized by cyclic facies changes. Sedimentological investigations of a detailed Quaternary section reveal that facies A is dominated by a high content of siliceous microfossils,...
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ftawi:oai:epic.awi.de:699 2024-09-15T17:47:04+00:00 Cyclic sedimentation at sites 745 and 746 Ehrmann, W. U. Grobe, Hannes 1991 application/pdf https://epic.awi.de/id/eprint/699/ https://epic.awi.de/id/eprint/699/1/Ehr1991b.pdf https://doi.org/10.2973/odp.proc.sr.119.123.1991 https://hdl.handle.net/10013/epic.11282 https://hdl.handle.net/10013/epic.11282.d001 unknown https://epic.awi.de/id/eprint/699/1/Ehr1991b.pdf https://hdl.handle.net/10013/epic.11282.d001 Ehrmann, W. U. and Grobe, H. orcid:0000-0002-4133-2218 (1991) Cyclic sedimentation at sites 745 and 746 , Proceedings of the Ocean Drilling Program, Scientific Results . doi:10.2973/odp.proc.sr.119.123.1991 <https://doi.org/10.2973/odp.proc.sr.119.123.1991> , hdl:10013/epic.11282 EPIC3Proceedings of the Ocean Drilling Program, Scientific Results, 119, pp. 225-237 Inbook peerRev 1991 ftawi https://doi.org/10.2973/odp.proc.sr.119.123.1991 2024-06-24T03:53:19Z The upper Miocene to Pleistocene sediments recovered at ODP Sites 745 and 746 in the Australian-Antarctic Basin are characterized by cyclic facies changes. Sedimentological investigations of a detailed Quaternary section reveal that facies A is dominated by a high content of siliceous microfossils, a relatively low terrigenous sediment content, an ice-rafted component, low concentrations of fine sediment particles, and a relatively high smectite content. This facies corresponds to interglacial sedimentary conditions. Facies B, in contrast, is characteristic of glacial conditions and is dominated by a large amount of terrigenous material and a smaller opaline component. There is also a prominent ice-rafted component. The microfossils commonly are reworked and broken. The clay mineral assemblages show higher proportions of glacially derived illite and chlorite.A combination of four different processes, attributed to glacial-interglacial cycles, was responsible for the cyclic facies changes during Quaternary time: transport by gravity, ice, and current and changes in primary productivity. Of great importance was the movement of the grounding line of the ice shelves, which directly influenced the intensity of ice rafting and of gravitational sediment transport to the deep sea. The extension of the ice shelves was also responsible for the generation of cold and erosive Antarctic Bottom Water, which controlled the grain-size distribution, particularly of the fine fraction, in the investigated area. Book Part Antarc* Antarctic Ice Shelves Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
unknown |
description |
The upper Miocene to Pleistocene sediments recovered at ODP Sites 745 and 746 in the Australian-Antarctic Basin are characterized by cyclic facies changes. Sedimentological investigations of a detailed Quaternary section reveal that facies A is dominated by a high content of siliceous microfossils, a relatively low terrigenous sediment content, an ice-rafted component, low concentrations of fine sediment particles, and a relatively high smectite content. This facies corresponds to interglacial sedimentary conditions. Facies B, in contrast, is characteristic of glacial conditions and is dominated by a large amount of terrigenous material and a smaller opaline component. There is also a prominent ice-rafted component. The microfossils commonly are reworked and broken. The clay mineral assemblages show higher proportions of glacially derived illite and chlorite.A combination of four different processes, attributed to glacial-interglacial cycles, was responsible for the cyclic facies changes during Quaternary time: transport by gravity, ice, and current and changes in primary productivity. Of great importance was the movement of the grounding line of the ice shelves, which directly influenced the intensity of ice rafting and of gravitational sediment transport to the deep sea. The extension of the ice shelves was also responsible for the generation of cold and erosive Antarctic Bottom Water, which controlled the grain-size distribution, particularly of the fine fraction, in the investigated area. |
format |
Book Part |
author |
Ehrmann, W. U. Grobe, Hannes |
spellingShingle |
Ehrmann, W. U. Grobe, Hannes Cyclic sedimentation at sites 745 and 746 |
author_facet |
Ehrmann, W. U. Grobe, Hannes |
author_sort |
Ehrmann, W. U. |
title |
Cyclic sedimentation at sites 745 and 746 |
title_short |
Cyclic sedimentation at sites 745 and 746 |
title_full |
Cyclic sedimentation at sites 745 and 746 |
title_fullStr |
Cyclic sedimentation at sites 745 and 746 |
title_full_unstemmed |
Cyclic sedimentation at sites 745 and 746 |
title_sort |
cyclic sedimentation at sites 745 and 746 |
publishDate |
1991 |
url |
https://epic.awi.de/id/eprint/699/ https://epic.awi.de/id/eprint/699/1/Ehr1991b.pdf https://doi.org/10.2973/odp.proc.sr.119.123.1991 https://hdl.handle.net/10013/epic.11282 https://hdl.handle.net/10013/epic.11282.d001 |
genre |
Antarc* Antarctic Ice Shelves |
genre_facet |
Antarc* Antarctic Ice Shelves |
op_source |
EPIC3Proceedings of the Ocean Drilling Program, Scientific Results, 119, pp. 225-237 |
op_relation |
https://epic.awi.de/id/eprint/699/1/Ehr1991b.pdf https://hdl.handle.net/10013/epic.11282.d001 Ehrmann, W. U. and Grobe, H. orcid:0000-0002-4133-2218 (1991) Cyclic sedimentation at sites 745 and 746 , Proceedings of the Ocean Drilling Program, Scientific Results . doi:10.2973/odp.proc.sr.119.123.1991 <https://doi.org/10.2973/odp.proc.sr.119.123.1991> , hdl:10013/epic.11282 |
op_doi |
https://doi.org/10.2973/odp.proc.sr.119.123.1991 |
_version_ |
1810495621650448384 |