Palaeoenvironmental records from the West Antarctic Peninsula drift sediments over the last 75 ka
Published:January 01, 2013
Maryline J. Vautravers, David A. Hodell, James E. T. Channell, Claus-Dieter Hillenbrand, Mike Hall, James Smith, Robert D. Larter, 2013. "Palaeoenvironmental records from the West Antarctic Peninsula drift sediments over the last 75 ka", Antarctic Palaeoenvironments and Earth-Surface Processes, M. J. Hambrey, P. F. Barker, P. J. Barrett, V. Bowman, B. Davies, J. L. Smellie, M. Tranter
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We present results of a multi-proxy study on marine sediment core JR179-PC466 recovered from the crest of a sediment drift off the West Antarctic Peninsula at approximately 2300 m water depth. The 10.45 m-long core consists dominantly of glaciomarine terrigenous sediments, with only traces of calcium carbonate (<1 wt%). Despite the very low abundance of calcareous foraminifera, planktonic shell numbers are sufficient for stable isotope analyses in two-thirds of the samples studied. The core chronology is based on oxygen isotope stratigraphy and correlation of its relative palaeomagnetic intensity (RPI) with a stacked reference curve. According to the age model, core PC466 spans the last 75 ka, with average sedimentation rates of between about 4 and 25 cm ka−1. Planktonic foraminifera abundances fluctuate between 0 and 30 individuals per gram throughout the core, with minima observed during Marine Isotope Stage (MIS) 2 (14–29 ka before present, BP) and MIS4 (57–71 ka BP). Planktonic foraminifera are present in the Holocene but more abundant in sediments deposited during MIS3 (29–57 ka BP), owing to less dilution by terrigenous detritus and/or better carbonate preservation. During MIS3, foraminifera maxima correlate with Antarctic warming events as recorded in the δ18O signal of the EPICA Dronning Maud Land (EDML) ice core. They indicate higher planktonic foraminifera production and better carbonate preservation west of the Antarctic Peninsula during that time. The abundance of ice-rafted detritus (IRD) in core PC466 increased during the last deglaciation between about 19 and 11 ka BP, when numerous icebergs drifted across the core site, thereby releasing IRD. During this time, sea-level rise destabilized the Antarctic Peninsula (APIS) and West Antarctic (WAIS) ice sheets that had advanced onto the shelf during the sea-level low-stand of the Last Glacial Maximum (LGM; c. 19–23 ka BP). Overall, our results demonstrate that it is possible to establish an age model and reconstruct palaeoceanographical and climatic changes at high temporal resolution from sedimentary sequences recovered at 2300 m water depth from a West Antarctic drift.
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Antarctic Palaeoenvironments and Earth-Surface Processes
The volume highlights developments in our understanding of the palaeogeographical, palaeobiological, palaeoclimatic and cryospheric evolution of Antarctica. It focuses on the sedimentary record from the Devonian to the Quaternary Period. It features tectonic evolution and stratigraphy, as well as processes taking place adjacent to, beneath and beyond the ice-sheet margin, including the continental shelf.
The contributions in this volume include several invited review papers, as well as original research papers arising from the International Symposium on Antarctic Earth Sciences in Edinburgh, in July 2011. These papers demonstrate a remarkable diversity of Earth science interests in the Antarctic. Following international trends, there is particular emphasis on the Cenozoic Era, reflecting the increasing emphasis on the documentation and understanding of the past record of ice-sheet fluctuations. Furthermore, Antarctic Earth history is providing us with important information about potential future trends, as the impact of global warming is increasingly felt on the continent and its ocean.