Provenance changes between recent and glacial-time sediments in the Amundsen Sea embayment, West Antarctica: clay mineral assemblage evidence

• Published in: Antarctic Science
• Main Authors: Ehrmann, Werner, Hillenbrand, Claus-Dieter, Smith, James A., Graham, Alastair G.C., Kuhn, Gerhard, Larter, Robert D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2011
• Subjects: Glaciology; Antarctic; West Antarctica; Amundsen Sea; West Antarctic Ice Sheet; Byrd; Pine Island Glacier; Marie Byrd Land; Thwaites Glacier; Ellsworth Land; Byrd Subglacial Basin; Antarc*; Antarctic Science; Antarctica; Ice Sheet; Pine Island
• Online Access: http://nora.nerc.ac.uk/id/eprint/15692/; https://nora.nerc.ac.uk/id/eprint/15692/1/_ANS_ANS23_05_S0954102011000320a.pdf; http://journals.cambridge.org/abstract_S0954102011000320

The Amundsen Sea embayment is a probable site for the initiation of a future collapse of the West Antarctic Ice Sheet. This paper contributes to a better understanding of the transport pathways of subglacial sediments into this embayment at present and during the last glacial period. It discusses the clay mineral composition of sediment samples taken from the seafloor surface and marine cores in order to decipher spatial and temporal changes in the sediment provenance. The most striking feature in the present-day clay mineral distribution is the high concentration of kaolinite, which is mainly supplied by the Thwaites Glacier system and indicates the presence of hitherto unknown kaolinite-bearing sedimentary strata in the hinterland, probably in the Byrd Subglacial Basin. The main illite input is via the Pine Island Glacier. Smectite originates from the erosion of volcanic rocks in Ellsworth Land and western Marie Byrd Land. The clay mineral assemblages in diamictons deposited during the last glacial period are distinctly different from those in corresponding surface sediments. This relationship indicates that glacial sediment sources were different from modern ones, which could reflect changes in the catchment areas of the glaciers and ice streams.