Using seafloor characteristics as indicators for past, modern and future marine environments in Potter Cove, King George Island, Antarctica

• Main Author: Wölfl, Anne-Cathrin
• Other Authors: Betzler, Christian (Prof. Dr.)
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky 2015
• Subjects: Antarctica; Hydroacoustics; Seafloor Classification; Deglaciation History; Climate Change; 550 Geowissenschaften; 38.48 Marine Geologie; ddc:550; Austral; King George Island; South Shetland Islands; Potter Cove; Outer Cove; Antarc*; Antarktis*
• Online Access: http://nbn-resolving.de/urn:nbn:de:gbv:18-73806; https://ediss.sub.uni-hamburg.de/handle/ediss/6398

The objective of this PhD thesis is to delineate past, modern and future environments in Potter Cove, a small tributary embayment on King George Island, South Shetland Islands, Antarctica. It is aimed to assess past and modern impacts of climate change on this representative coastal system and to suggest future developments under the recent climatic trend. Seafloor characteristics have been investigated using hydroacoustics, underwater video recordings and sediment samples. Multivariate analyses were applied to faciliate and improve the data processing and the objective interpretation of the data sets. The majority of the data was acquired during two field campaigns within the international research programme IMCOAST during the austral summer season of 2010/2011 and 2011/2012. The deglaciation history of King George Island is still debated and subject of numerous scientific studies. In this thesis, high-resolution swath bathymetry, shallow seismics and one sediment core allowed the delineation of submarine landforms and sub-bottom characteristics in Potter Cove that are instrumental to reconstruct glacial dynamics during the Late Holocene. Furthermore, ancient and modern environmental processes are described and interpreted. The results reveal the occurrence of moraine deposits and glacial lineations in the inner part of the cove. The seafloor is made up of glacial debris that has been deposited underneath or in direct vicinity of grounded ice. This deposit is covered by a thin layer of meltwater-derived sediments. The moraine ridges evidence the occurrence of glacial stillstands and potential readvances since 2.6 cal kyr BP. Landforms on the slope in the outer cove include channel structures, ice plough marks and pockmarks. The seafloor consists of gravity flow deposits that result from sediment disturbance by deep-keeled icebergs and from sediment overload. The latter was most likely caused by the accumulation of glacial debris on top of the slope, when the glacier was situated in direct proximity. ...