Insights into the behaviour of the Pliocene East Antarctic ice sheet from provenance studies of marine sediments using radiogenic isotopoes

• Main Author: Cook, Carys Patricia
• Format: Text
• Language: unknown
• Published: Imperial College London 2013
• Subjects: Antarctic; East Antarctic Ice Sheet; West Antarctic Ice Sheet; Wilkes Subglacial Basin; Antarc*; Ice Sheet; Iceberg*
• Online Access: https://dx.doi.org/10.25560/14262; http://spiral.imperial.ac.uk/handle/10044/1/14262

Direct evidence for the response of Earth’s largest continental ice mass, the East Antarctic ice sheet (EAIS), to climatic warmth is extremely limited. The primary aim of this thesis is to improve understanding of the behaviour of the EAIS during the warmer-than-present Pliocene Epoch (2.58 to 5.33 million years ago). To this end, I analysed the radiogenic neodymium and strontium isotopic provenance of fine-grained (<63μm) Pliocene detrital marine sediments deposited offshore of the East Antarctic continent, which can provide information on source bedrock characteristics, continental erosional patterns and marine sediment depositional processes. In addition, I also analysed argon isotopic ages of ice-rafted hornblende grains (>150μm), to infer sites of major iceberg production events through time. Within this thesis, I present Pliocene marine sediment data from various cores drilled from the East Antarctic margin, thereby developing a detailed framework for linking provenance variability to ice sheet behaviour. My key findings have been collated into five distinct chapters, providing: i) the first evidence for significant retreat of the EAIS in the low-lying Wilkes Subglacial Basin in response to the earliest Pliocene climatic warmth; ii) insights into the benefits and pitfalls associated with utilising different tools in glaciomarine sediment provenance studies; iii) constraints on the behaviour of the EAIS and West Antarctic ice sheet during the warmth of Pleistocene super-interglacial, Marine Isotope Stage 31; iv) insights into the role of declining sea surface termperatures during the Pliocene on the flux and provenance of distally sourced ice-rafted detritus, along with evidence for potential ice sheet destabilisation events in the Aurora Subglacial Basin during Pliocene interglacials; and v) advances in understanding of the evolution of the EAIS during the Late Pliocene climatic transition, and its role in global Pliocene climate change. Hence, the findings presented within this thesis provide new and significant evidence for the behaviour of the EAIS during the Pliocene, and suggest it has in the past been more sensitive to climatic change than previously realised.