Cycles, Rhythms, and Events in Quaternary Arctic and Antarctic Glaciomarine Deposits
Highly variable fades patterns of sub-Arctic glaciomarine continental margin environments contrast with less pronounced variations in Antarctic deposits. Shallow portions of the sub-Arctic shelves reveal regressive facies successions comprising basal lodgement till and high energy reworked top seque...
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| Other Authors: | , |
| Format: | Book Part |
| Language: | English |
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Springer Netherlands
1990
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| Online Access: | https://oceanrep.geomar.de/id/eprint/33231/ https://oceanrep.geomar.de/id/eprint/33231/1/Henrich%201990.pdf https://doi.org/10.1007/978-94-009-2029-3_12 |
| Summary: | Highly variable fades patterns of sub-Arctic glaciomarine continental margin environments contrast with less pronounced variations in Antarctic deposits. Shallow portions of the sub-Arctic shelves reveal regressive facies successions comprising basal lodgement till and high energy reworked top sequences during glacio-isostatic uplift. Deeper portions of sub-Arctic shelves record advance/retreat cycles of continental ice with up to 150 m thick glacigenic units which are separated by glacial erosional surfaces. Greatest thicknesses occur on the shelf break and upper slope with depocenters situated at the mouth fans. Prograding slope sequences reveal a complex sigmoid-oblique seismic character formed by alternating build-up during glacial progradation and depositional bypass/erosion in the topset during interglacial periods. Antarctic shelf deposits reveal biogenic siliceous muds or gravelly diamictons with admixtures of a monogenetic biogenic epifauna deposited at low sedimentation rates. Sub-Arctic and Antarctic deep-sea sediment records reflect glacial/interglacial variations in carbonate and opal productivity and ice-rafted debris input. In Norwegian — Greenland Sea’s deep sea pelagic environments widespread distribution of dark diamictons indicates extensive advances of the continental ice-sheets onto the shelves and permits connection of open ocean with shelf records. In the Weddell Sea, glacial, transitional and interglacial facies patterns correspond to advance/retreat cycles of the Antarctic ice-sheet, episodic development of floating ice-shelves, variations in the extension of sea ice coverage and cyclic development of polynyas within the Weddell Sea sea ice-cover. |
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