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

南极洲和南大洋在地球气候中发挥着核心作用。为了改进预测冰量和海平面变化的气候模型，了解影响南极冰量平衡的因素至关重要。三个东南极沉积物岩心的地球化学可能揭示南极洲冰盖在过去的波动。这项研究将由东京大学的Yusuke Yokoyama博士监督。 必要的仪器和设备，以及横山博士在地球化学方面的专业知识，使这里成为一个理想的研究地点。南极冰量的减少往往与大陆架上温暖的海洋沃茨的存在同时发生，这表明冰架系统对海洋温度很敏感。确定冰架对海洋热量的敏感性对于了解冰盖稳定性至关重要。晚第四纪（125 ka-present）海洋沉积物收集在普里兹湾，东南极洲保存冰架波动的证据。三个核心从Preniz湾揭示至少四个硅质泥和软泥单位与冰川海洋单位互层，分别代表开放的海洋条件（无冰）和冰川条件（冰覆盖）。交替的开阔海洋和冰川条件表明，普里兹湾的埃默里冰架系统（AIS）随着时间的推移而波动。本研究将通过测量三个Preniz湾沉积物岩心中同位素铍10（10 Be）的相对丰度来研究这种变化。10 Be的相对丰度是沉积环境的间接测量;较高的10 Be丰度表明开阔的海洋条件。建立Preniz湾的沉积环境对于生成更可靠的晚第四纪AIS历史至关重要。揭开南极洲东部最大出口冰川的历史与气候变化正在破坏南极冰盖的稳定，并对未来海平面上升产生影响的担忧有关。这个NSF EAPSI奖是与日本科学促进协会合作资助的。

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.