Late Pleistocene oceanographic and depositional variations along the Wilkes Land margin (East Antarctica) reconstructed with geochemical proxies in deep-sea sediments
Water masses and depositional environments over the last 500 ka were reconstructed using absolute and relative abundances of lithogenous, biogenous and redox-sensitive elements in four sediment cores from two channel-levee systems of the Wilkes Land continental slope (East Antarctica). Sediments old...
Published in: | Global and Planetary Change |
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Main Authors: | , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
2020
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Subjects: | |
Online Access: | https://epic.awi.de/id/eprint/50542/ https://doi.org/10.1016/j.gloplacha.2019.103045 https://hdl.handle.net/10013/epic.606d0978-26d0-4bbf-9ade-f315c133fc50 |
Summary: | Water masses and depositional environments over the last 500 ka were reconstructed using absolute and relative abundances of lithogenous, biogenous and redox-sensitive elements in four sediment cores from two channel-levee systems of the Wilkes Land continental slope (East Antarctica). Sediments older than the Mid-Bruhnes event (MBE, 430 ka BP) show reduced glacial/interglacial variability in the abundance of elements associated to the terrigenous mineral phases (i.e. Al, Ti, Fe and partly Si). This suggests minor ice-sheet size changes occurred in the Antarctic margin during the pre-MBE “lukewarm” interval. Post-MBE sediments record instead a high variability between glacial and interglacial periods in the concentration of terrigenous and biogenous (i.e. Ca, Ba) elements suggesting larger amplitude changes in both ice-sheet size and ocean conditions toward the gradual establishment of last glacial cycle conditions. Moreover, a marked increase of Mn during the glacial to interglacial transitions, indicates a post-depositional migration of the redox front and re-oxidation of the surface sediment layers linked to major changes in bottom water oxygen conditions associated to Antarctic Bottom Water formation along the margin at the onset of deglaciations. |
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