Late Quaternary environmental history of Rauer Group, East Antarctica
In East Antarctica, small ice-free coastal areas are unique environments, located between the East Antarctic Ice Sheet (EAIS) and its outlet glacier systems on the one hand and the Southern Ocean on the other. Rauer Group is an ice-free archipelago in eastern Prydz Bay, which has been visited in Mar...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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2010
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| Online Access: | https://kups.ub.uni-koeln.de/3144/ https://kups.ub.uni-koeln.de/3144/1/Dissertation_Sonja_Berg.pdf |
| Summary: | In East Antarctica, small ice-free coastal areas are unique environments, located between the East Antarctic Ice Sheet (EAIS) and its outlet glacier systems on the one hand and the Southern Ocean on the other. Rauer Group is an ice-free archipelago in eastern Prydz Bay, which has been visited in March 2007. Geomorphological studies have been conducted there in order to shed light on the glacial history of the area. The recovery of long sediment cores from three marine inlets and one lake provided the possibility to reconstruct the late Pleistocene and Holocene environmental and climate history of the area for the first time. Since knowledge on climate and glacial history around East Antarctica is relatively sparse, this study contributes significantly to a broader understanding of the late Quaternary evolution of the region. The reconstructions presented in this thesis are based on a multi-proxy approach, comprising sedimentological, biogeochemical and paleontological studies on sedimentary records from lakes and marine inlets. Chronologies of the records have been obtained by radiocarbon dating. Radiocarbon ages from three different records indicate ice-free conditions on the islands in the late Pleistocene between 40-30 14C ka BP (44.7-34 cal ka BP). The presence of lacustrine as well as marine environments on/at Filla Island suggest that the EAIS reached only insignificantly beyond its present margin during that period. At the same time, relative sea-level reconstructions point to increased ice load in vicinity of the coast and a steeper than present ice sheet profile. A subsequent glacial overriding due to EAIS expansion during the Last Glacial Maximum can be inferred from a till layer and a hiatus in sediment cores from two marine basins, respectively. Glacial overriding within the last glacial is also suggested by the geomorphology of the islands. The inlets became ice-free prior to 11,200 cal yr BP, when biogenic sedimentation started. Deglaciation processes in the catchments, however, influenced the ... |
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