The Ross Ice Shelf dynamics during the Late Pliocene and the Early Pleistocene climate conditions warmer than today?


Contact
gerhard.kuhn [ at ] awi.de

Abstract

In Antarctica, the largest inland ice masses on Earth are stored. The growth and the retreat of ice sheets play a major role in the global ocean current system and climate. The melting and collapse of large ice shelves may cause a significant sea level rise, because of accelerated inland ice glacier surges into the ocean.The ANDRILL (Antarctic Geological Drilling) MIS deep drilling project (McMurdo Sound, NE Ross Ice Shelf, core AND-1B drilled during austral summer 2006/2007) is located in a flexural moat basin filled with glaciomarine, terrigenous, volcanic, and biogenic sediments. This basin contains a well-preserved, outstanding record of approximately 14 million years of paleoclimate history. For the first time, sediments beneath an ice shelf were drilled, which provides a unique opportunity to investigate the variability of the Ross Ice Shelf. The sediment core covers a time period much longer than any Antarctic ice core record.During the drilling phase, some major and minor chemical elements were measured directly on split cores using a non-destructive X-Ray Fluorescence Core Scanner method (XRF-CS). In addition, colour data were collected using an integrated Line Scan camera in the XRF-CS system and a Minolta 2002 handheld spectrophotometer. Furthermore wet chemical analysis like the investigation of TOC, biogenic opal, major and minor elements with ICP-MS and conventional XRF were done on core samples to contribute to the better understanding of geochemical sediment properties. Colour data will be correlated to the XRF-CS data to received more and higher resolved information about the sediment composition.The interpretation of rapid paleoclimatic changes in the Antarctic realm, especially to understand the behaviour of the Ross Ice Shelf during the past million years, is one target of our study. The high-resolution data set of non-destructive XRF-core and colour scans make it possible to estimate environmental changes on small time scales that will be linked to climate changes. From the Late Pliocene a transition from diamictite to diatomites is described which implies a shifting from a retreating ice sheet to open marine conditions. In the Early Pleistocene, a number of cycles, alternating from glacial ice transported sediments to open water sedimentation, were observed. The diatomites represent time spans with high bioproductivity and reflect warmer conditions at the Antarctic margin than today.



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Conference (Talk)
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
23. internationale Polartagung der Dt. Gesellschaft für Polarforschung, 10.-14.März 2008, Münster..
Eprint ID
18860
Cite as
Helling, D. , Kuhn, G. and von Eynatten, H. (2008): The Ross Ice Shelf dynamics during the Late Pliocene and the Early Pleistocene climate conditions warmer than today? , 23. internationale Polartagung der Dt. Gesellschaft für Polarforschung, 10.-14.März 2008, Münster. .


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