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.

知识分子的优点：PIS提议研究威尔克斯和Aurora亚冰纹贝司区域期间南极冰盖的稳定性和动力学。模型表明，在这些低洼地区，冰盖对变暖最敏感。这项研究很重要，因为几乎没有直接证据表明在温暖的条件下，东南极冰盖的哪些部分变得不稳定。在一项试点研究中，PIS表明，下层冰冰碎片（IRD）的同位素地球化学特征可以与连续的源区域联系起来，指示冰盖的哪些部分到达海岸并产生了含有IRD IRD的冰山。他们的最初结果表明，在中新世晚期和上新世早期，有时从威尔克斯土地和阿德利土地沿海地区从威尔克斯土地和阿德利土地沿海地区排出。在这项研究中，PIS将分析来自南极洲东部连续升起的IODP沉积物核心的IRD。通过分析每个核心的40AR/39AR年龄，U-PB年龄，U-PB年龄和SM-ND同位素的良好分数，它们将能够指示East Antarctica的ICE范围和动力学。 PI还将对其中一些层进行详细研究，以表征冰上冰期事件的解剖结构，并更好地了解冰的不稳定机理。Broader的影响：收集到的数据对各种领域的科学家来说至关重要。该项目将涉及一名本科生和一个在LDEO的暑期实习生，以及伦敦帝国学院的一名研究生。该项目将暴露于最先进的方法以及国际研究团队。该项目的数据将存入在线数据库（SEDDB）中，所有结果和方法将通过同行评审期刊的出版物和国际会议的出勤率提供给科学界的所有结果和方法。