Marine geological constraints for the grounding-line position of the Antarctic Ice Sheet on the southern Weddell Sea shelf at the Last Glacial Maximum

摘要: Abstract The history of grounded ice-sheet extent on the southern Weddell Sea shelf during Last Glacial Maximum (LGM) and timing post-LGM retreat are poorly constrained. Several glaciological models reconstructed widespread grounding major thickening Antarctic Ice Sheet in sector at LGM. In contrast, recently published onshore data modelling results concluded only very limited LGM-thickening glaciers ice streams feeding into modern Filchner Ronne shelves. These studies that LGM shelves rather than covered troughs, two deep palaeo-ice stream troughs eroded shelf. Here we review previously unpublished marine geophysical geological from stratigraphy geometry reflectors acoustic sub-bottom profiles similar to those other West where had advanced break Numerous cores recovered sequences with properties typical for subglacially deposited tills or compacted sediments. sets give evidence across past, thereby even deepest parts troughs. Radiocarbon dates glaciomarine sediments overlying subglacial deposits limited, but indicate occurred started before ∼15.1 corrected 14C kyrs present (BP) outer ∼7.7 14C kyrs BP inner shelf, which is broadly synchronous sectors. apparent mismatch between reconstructions terrestrial can be attributed low surface (similar “ice plains”) through Trough Considering global sea-level low-stand ∼130 m below present, a slope expanded LGM-ice sheet reconcile grounding-line advance hinterland. This scenario implies growth drawdown throughout last deglaciation could have made minor contributions fluctuations these times.