Glacial proxies of East Antarctic shield basement in Wilkes Land, Antarctica

南极洲威尔克斯地东南极地盾地下室的冰川代理

• 批准号: 0337858
• 负责人: John Goodge
• 金额: --
• 依托单位: University of Minnesota Duluth
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-15 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0337858&HistoricalAwards=false
• 关键词: Glacial; proxies; East; Antarctic; shield

This work will determine the age and provenance of glacially derived marine sediments from the coastal regions of Wilkes Land, Antarctica. These deposits may offer insight into the history of the East Antarctic Shield (EAS), which is amongst the oldest sections of continental crust on Earth, but cannot be studied directly because of nearly complete ice sheet coverage. The study will use Australian National University's SHRIMP ion microprobe to date zircon and monazite found in the sediments. Samples of interest include polymictic pebble and cobble clasts obtained from dredge hauls of tills, as well as sand-matrix fractions from cores of glacial diamicts on the continental margin. Individual clasts of igneous and metamorphic rocks from tills will be selected for zircon and/or monazite age dating, whereas detrital zircons from stratified and non-stratified diamictons will be analyzed for composite zircon provenance analysis. In addition, detrital zircon ages will be determined for Beacon Supergroup sandstones to evaluate recycling of zircon in Phanerozoic basins. Integration of ages obtained from both sources will provide a good representation of the EAS terrains underlying the Wilkes Land ice sheet. This project will allow us to learn more about the remote continental interior and improve our ability to interpret past ice-flow patterns without further environmental impact on Antarctica. The results will improve our understanding of Precambrian tectonics and crustal evolution, and help target future over-ice geophysical surveys and basement drilling projects currently under consideration. In terms of broader impacts, the project will provide educational and training opportunities for undergraduate students in Earth science.

这项工作将确定来自南极洲威尔克斯地沿海地区的冰川海洋沉积物的年龄和来源。这些沉积物可能有助于了解东南极地盾（EAS）的历史，EAS是地球上最古老的大陆地壳部分之一，但由于几乎完全覆盖冰盖，因此无法直接研究。这项研究将使用澳大利亚国立大学的SHRIMP离子探针来测定沉积物中发现的锆石和独居石的年代。我们感兴趣的样品包括从挖泥船中获得的多晶卵石和卵石碎屑，以及从大陆边缘冰川岩心中获得的砂基质组分。将选择来自tills的火成岩和变质岩的单个碎屑进行锆石和/或独居石的年龄测定，而来自分层和非分层的碎屑锆石将进行综合锆石物源分析。此外，对显生宙盆地的Beacon超群砂岩进行碎屑锆石年龄测定，评价其再循环作用。从两个来源获得的年龄综合将提供威尔克斯陆冰盖下的EAS地形的良好代表。这个项目将使我们能够更多地了解遥远的大陆内部，提高我们解释过去冰流模式的能力，而不会对南极洲造成进一步的环境影响。研究结果将提高我们对前寒武纪构造和地壳演化的认识，并有助于目前正在考虑的未来冰上地球物理调查和地下室钻探项目。就更广泛的影响而言，该项目将为地球科学的本科生提供教育和培训机会。