Small, deep shelf-basins and their sedimentary infill, western Bransfield Strait, Antarctic Peninsula

Abstract

A number of small but deep shelf-basins reaching water depths in excess of 1000 m have been identified west of the northern Antarctic Peninsula (NAP). The best known is Palmer Deep, a 1400 m deep erosional inner-shelf depression located off Anvers Island. Both stratigraphic observations and specific seafloor features in and around Palmer Deep have been linked to the development of a subglacial lake prior to or during the Last Glacial Maximum (LGM), followed by estuarine and open-marine conditions since that time (Domack et al. 2006). Here, several small shelf-basins are examined, located 200 km NE of Palmer Deep in western Bransfield Strait (Fig. 1a, g). Fig. 1. Small, deep shelf-basins in western Bransfield Strait. ( a ) Multibeam-bathymetric image. JPC-32 and JPC-33 are sediment cores that recovered Holocene diatom-bearing muds in their upper 10 m. NB, GB, FB and EB refer to Needle, Gullet, Fig and The Eye basins. Acquisition system Simrad EM12-S. Frequency 12.5 kHz. Grid-cell size 200 m (colour) and GEBCO_08 grid (grey). Land is from the Landsat Image Mosaic of Antarctica (US Geological Survey). ( b ) Fig Basin. ( c ) Gradient map of Fig Basin showing its flat floor and smooth to very steep slopes. ( d ) Map of Needle, Gullet and The Eye basins. ( e ) Fig Basin transverse (VE×4) and long-axis (VE×8) bathymetric profiles. ( f ) High-resolution …