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| Titel |
Modern foraminifera assemblages in the Amundsen Sea Embayment |
| VerfasserIn |
Patrycja Ewa Jernas, Gerhard Kuhn, Claus-Dieter Hillenbrand, Tine Lander Rasmussen, Matthias Forwick, Andreas Mackensen, Michael Schröder, James Smith, Johann Philipp Klages |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111892
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| Publikation (Nr.) |
 EGU/EGU2015-12040.pdf |
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| Zusammenfassung |
| The West Antarctic Ice Sheet (WAIS) is considered the most unstable part of the Antarctic Ice
Sheet. As the WAIS is mostly grounded below sea level, its stability is of great concern. A
collapse of large parts of the WAIS would result in a significant global sea-level rise. At
present, the WAIS shows dramatic ice loss in its Amundsen Sea sector, especially
in Pine Island Bay. Pine Island Glacier (PIG) is characterised by fast flow, major
thinning and rapid grounding-line retreat. Its mass los over recent decades is generally
attributed to melting caused by the inflow of warm Circumpolar Deep Water (CDW).
Future melting of PIG may result in a sea level tipping point, because it could trigger
widespread collapse of the WAIS, especially when considering ongoing climate
change.
Our research project aims to establish proxies (integration of foraminifera, sediment
properties and oceanographic data) for modern environmental conditions by analysing
seafloor surface sediments along a transect from the glacier proximal settings to the
middle-outer shelf in the eastern Amundsen Sea Embayment. These proxies will then be
applied on sediment records spanning the Holocene back to the Last Glacial Maximum for
reconstructing spatial and temporal variations of CDW upwelling and ice-ocean interactions
during the past c. 23,000 years. We will present preliminary results from the analyses of ten
short marine sediment cores (multi and box cores) collected during expeditions
JR179 (2008) and ANT-XXVI/3 (2010) along a transect from inner Pine Island
Bay to the middle-outer shelf part of the Abbot Palaeo-Ice Stream Trough at water
depths ranging from 458 m (middle shelf) to 1444 m (inner shelf). The sediment
cores are currently investigated for distribution patterns of planktonic and benthic
foraminifera and grain-size distribution at 1 cm resolution. Core tops (0-10 cm)
were stained with Rose Bengal for living benthic foraminifera investigations. The
chronology of the cores will be based on 210Pb and calibrated 14C dates. First
results reveal the presence of living benthic foraminifera in surface sediments of all
investigated cores suggesting that modern seabed surfaces were recovered. Moreover, a
core retrieved from a water depth of 793 m in the Abbot Palaeo-Ice Stream Trough
shows particularly high abundances of planktonic foraminifera Neogloboquadrina
pachyderma. |
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