History of the East Antarctic Ice Sheet since the mid-Miocene: New Evidence from Provenance of Ice-rafted Debris

中新世中期以来南极东部冰盖的历史：来自冰筏碎片来源的新证据

• 批准号: 0944489
• 负责人: Trevor Williams
• 金额: $ 24.3万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-15 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944489&HistoricalAwards=false
• 关键词: History; East; Antarctic; Ice; Sheet

Intellectual Merit: The PIs propose to study the stability and dynamics of the East Antarctic ice sheet during the Pliocene in the area of the Wilkes and Aurora subglacial basins. Models indicate the ice sheet is most sensitive to warming in these low-lying areas. This study is important as there is very little direct evidence about which parts of the East Antarctic ice sheet became unstable under warm conditions. In a pilot study the PIs have shown that the isotopic geochemical signature of downcore ice-rafted debris (IRD) can be linked to continental source areas indicating which parts of the ice sheet reached the coast and calved IRD-bearing icebergs. Their initial results suggest rapid iceberg discharge from the Wilkes Land and Adélie Land coastal areas at times in the late Miocene and early Pliocene. In this study the PIs will analyze IRD from IODP sediment cores collected on the continental rise off East Antarctica. By analyzing 40Ar/39Ar ages of hornblende IRD grains, U-Pb ages of zircons, and Sm-Nd isotopes of the fine fraction of several IRD-rich layers for each core, they will be able to fingerprint continental source areas that will indicated ice extent and dynamics on East Antarctica. The PIs will also carry out detailed studies across a few of these layers to characterize the anatomy of the ice-rafting event and better understand the mechanism of ice destabilization.Broader impacts: The data collected will be important for scientists in a broad variety of fields. The project will involve one undergraduate student and one summer intern at LDEO, and a graduate student at Imperial College London. The project will expose to cutting edge methodologies as well as an international research team. Data from the project will be deposited in the online databases (SedDB) and all results and methods will be made available to the scientific community through publications in peer-reviewed journals and attendance at international conferences.

学术价值：PI建议研究上新世期间威尔克斯和奥罗拉冰下盆地地区南极东部冰盖的稳定性和动态。模型表明冰盖对这些低洼地区的变暖最为敏感。这项研究很重要，因为几乎没有直接证据表明南极东部冰盖的哪些部分在温暖条件下变得不稳定。在一项试点研究中，PI 表明，下核的同位素地球化学特征。冰筏碎片（IRD）可以与大陆源区联系起来，表明冰盖的哪些部分到达了海岸并崩解了带有IRD的冰山。他们的初步结果表明，有时冰山会从威尔克斯地和阿德利地沿海地区快速排出。在这项研究中，PI 将通过分析 40Ar/39Ar 年龄来分析在南极洲东部大陆隆起收集的 IODP 沉积物岩心的 IRD。通过角闪石 IRD 颗粒、锆石的 U-Pb 年龄以及每个核心的几个富含 IRD 层的细小部分的 Sm-Nd 同位素，他们将能够确定大陆源区的指纹，从而指示东南极洲的冰范围和动态。 PI 还将对其中一些层进行详细研究，以描述冰漂流事件的解剖结构，并更好地了解冰不稳定的机制。 更广泛的影响：收集的数据将该项目将涉及 LDEO 的一名本科生和一名暑期实习生，以及伦敦帝国理工学院的一名研究生，该项目将接触最先进的方法和国际研究团队。该项目的数据将存储在在线数据库（SedDB）中，所有结果和方法将通过在同行评审期刊上发表文章和参加国际会议向科学界提供。