Stable isotope record and late Quaternary sedimentation rates at the Antarctic continental margin
Four cores from the Antarctic continental margin located between 50 and 200 km from the present-day ice shelf edge, were selected for sedimentological and mass spectrometer analysis. The first stable isotope records of the Southern Polar Ocean can be correlated in detail with global isotope stratigr...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
1990
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/1073/ https://epic.awi.de/id/eprint/1073/1/Gro1990a.pdf https://hdl.handle.net/10013/epic.11660 https://hdl.handle.net/10013/epic.11660.d001 |
| Summary: | Four cores from the Antarctic continental margin located between 50 and 200 km from the present-day ice shelf edge, were selected for sedimentological and mass spectrometer analysis. The first stable isotope records of the Southern Polar Ocean can be correlated in detail with global isotope stratigraphy. Together with magnetostratigraphic, sedi¬mentological and micropaleontological data, the record provides stratigraphic and paleoceanographic information back to the Jaramillo subchron (910 kyr).Although the isotope values have been altered by diagenetic processes in the sediments, which are poor in carbonate, an interpretation is possible via correlation with the sedimentological parameters. Oxygen isotope data give indications for a meltwater spike at the beginning of interglacials, when large scale melting of parts of the ice shelves took place. The synchronous record of the benthic and planktonic d13C-signals reflect continuous bottom water formation also during glacials.Primary productivity was strictly reduced during glacials due to continuous ice coverage in the Weddell Sea. The climatic improvement at the beginning of an interglacial is associated with peak values in biologic activity lasting for about 15 kyr.During one climatic cycle, mean sedimentation rates at the continental margin decrease with increasing distance from the continent from 5.2 to 1.3 cm/kyr. Maximum sedimentation rates of 25 cm/kyr at the beginning of an interglacial down to 0.6 cm/kyr during glacial periods have been calculated. The rate is mainly controlled by movements of the ice shelf edge and ice rafting. |
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