EAPSI: Using geochemistry to unravel the history of an East Antarctic ice shelf system

Guitard Michelle E, Saint Petersburg FL

Investigators

Abstract

Antarctica and the Southern Ocean play a central role in Earth's climate. To improve the climate models that predict changes in ice volume and sea level, it is important to understand factors affecting Antarctic ice mass balance. The geochemistry of three East Antarctic sediment cores may reveal how Antarctica's ice sheets fluctuated in the past. This research will be supervised by Dr. Yusuke Yokoyama, at the University of Tokyo. Necessary instruments and facilities, as well as Dr. Yokoyama's expertise in geochemistry make this an ideal research opportunity site. Reductions in Antarctic ice mass often co-occur with the presence of warm oceanic waters on the continental shelf, suggesting that ice shelf systems are sensitive to ocean temperatures. Identifying the sensitivity of ice shelves to ocean heat is critical for understanding ice sheet stability. Late Quaternary (125 ka-present) marine sediments collected in Prydz Bay, East Antarctica preserve evidence of ice shelf fluctuations. Three cores from Prydz Bay reveal at least four siliceous mud and ooze units interbedded with glacial marine units, representing open-marine conditions (ice-free) and glacial conditions (ice-covered), respectively. Alternating open-marine and glacial conditions suggest the Amery Ice Shelf system (AIS) in Prydz Bay has fluctuated through time. This research will examine this variation by measuring the relative abundance the isotope, beryllium 10 (10Be) in three Prydz Bay sediment cores. Relative abundance of 10Be is an indirect measurement of depositional environment; a higher abundance of 10Be indicates open-marine conditions. Establishing the depositional environment in Prydz Bay is essential to generating a more reliable late Quaternary AIS history. Unveiling the history of the largest outlet glacier in East Antarctica is relevant to concerns that climate change is destabilizing Antarctic ice sheets, with implications for future sea level rise. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.