Submarine landforms and seismic facies in Börgen Bay, Anvers Island: Imprints of the past glacial behaviour and climate influence in the Western Antarctic Peninsula

Abstract

The glacimarine processes in the Western Antarctic Peninsula have been intensified since the “Little Ice Age”. These have been recorded in the distribution and shape of glacial submarine landforms and glacial sub-bottom stratigraphy. In this study, the dominant factors of the past ice flow behaviour and glacimarine sedimentary processes in Börgen Bay, Anvers Island, are identified and analyzed. The results indicate that the outer bay linear features are associable to the past ice flow during the Last Glacial Maximum. After that, a general deglaciation period occurred, with some readvances and short stillstand, interpreted by the presence of moraines and small transverse ridges. The presence of “pinning points” on the coast, could affect the glacier movements and favour the generation of moraines. Differences in the ice flow behaviour between the bay arms, are due to factors such as bathymetry, and the size of the drainage basin and glacier front. Main sedimentary processes are ice-rafting and subglacial flows, marked by chaotic seismic facies, and gravity flows identified by monticulated and transparent seismic facies, and also sediment plumes contribution, creating laminated facies in the proximal area basins. Those sedimentary mechanisms and landforms agree with a wet polar climate, but some of them would indicate a warmer climate shifting, that is necessary to prove with systematic future measurements.