Palaeoenvironment of the Weddell Sea and Amundsen Sea - eastern Ross Sea basins, Antarctica: Insights from comprehensive seismostratigraphic analysis

Abstract

In combining existing multichannel seismic reflection seismic data in the Weddell Sea deep-sea basin, with existing and newly acquired data in the Amundsen Sea and Ross Sea basins, previously unknown sequences representing the pre-glacial to glacial palaeoenvironmental development of the West Antarctic Margin were identified. Pre-glacial sediment deposition centres seemed to have changed near or after the Eocene/Oligocene boundary (~34 Ma) when the first major ice sheets advanced to and across the shelf. The middle Miocene (~16 Ma) full glacial sequences indicate a new depocentre formed North of the Amundsen Sea Embayment. Smaller depocentres in the Bellingshausen Sea and Antarctic Peninsula basins, shifted eastward. Calculations indicate ~4.6 km (~10.2 million km3) of West Antarctica's landmass were eroded since the Late Cretaceous and deposited in the Southern Pacific. This has implications for the palaeotopographic and palaeobathymetric reconstructions, and ice sheet climate models.