Late Pleistocene oceanographic and depositional variations along the Wilkes Land margin (East Antarctica) reconstructed with geochemical proxies in deep-sea sediments


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Gerhard.Kuhn [ at ] awi.de

Abstract

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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ISI/Scopus peer-reviewed
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Published
Eprint ID
50542
DOI 10.1016/j.gloplacha.2019.103045

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Jimenez-Espejo, F. J. , Presti, M. , Kuhn, G. , Mckay, R. , Crosta, X. , Escutia, C. , Lucchi, R. G. , Tolotti, R. , Yoshimura, T. , Ortega Huertas, M. , Macrì, P. , Caburlotto, A. and De Santis, L. (2020): Late Pleistocene oceanographic and depositional variations along the Wilkes Land margin (East Antarctica) reconstructed with geochemical proxies in deep-sea sediments , Global and Planetary Change, 184 , p. 103045 . doi: 10.1016/j.gloplacha.2019.103045


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