East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains

Abstract: Intellectual Merit: The PIs proposed a provenance study of glacial deposits in the Ross Embayment that will provide a broad scale geochronologic survey of detrital minerals in till to help characterize bedrock beneath the East Antarctic ice sheet and constrain Antarctica?s glacial history. This project capitalizes on previous investments in field sampling. Analytical tools applied to single mineral grains extracted from existing collections of glacial till will generate ?fingerprints? of East Antarctic outlet glaciers and West Antarctic till to refine paleo-ice flow models for the Ross Embayment during the last glacial maximum, older records from ANDRILL cores, and to assess IRD sources in the Southern Ocean. New provenance tracers will include a suite of geochronological methods that together provide greater insights into the orogenic and erosional history the region. This project will include U/Pb of detrital zircons, (U-Th)/He on a subset of the U/Pb dated zircons, as well as Ar-Ar of detrital hornblende, mica and feldspars.
Broader Impacts: This research will train one M.S. student at IUPUI, a Ph.D. student at Columbia, and several undergraduates at both institutions. Graduate students involved in the project will be involved in mentoring undergraduate researchers. Incorporation of research discoveries will be brought into the classroom by providing concrete examples and exercises at the appropriate level. Licht and Columbia graduate student E. Pierce are developing outreach projects with local secondary school teachers to investigate the provenance of glacial materials in their local areas. The research will have broad applicability to many fields.

摘要：
学术价值：本项目首席研究员（Principal Investigators，PIs）拟开展罗斯海盆（Ross Embayment）内冰川沉积的物源研究，通过对冰碛物（glacial till）中碎屑矿物开展大尺度地质年代学调查，以明确东南极冰盖（East Antarctic Ice Sheet）下伏基岩特征，并限定南极冰川演化历史。本项目依托此前野外采样工作的既有投入，将对现有冰川冰碛物馆藏中提取的单矿物颗粒开展分析测试，以此生成东南极冰外流冰川与西南极冰碛物的“物源指纹”，进而优化末次冰盛期、ANDRILL岩芯（ANDRILL）记录的更古老时段罗斯海盆古冰流模型，并评估南大洋（Southern Ocean）中的冰筏碎屑（Ice Rafted Debris，IRD）物源。本次研究将采用一系列地质年代学方法作为新型物源示踪剂，以深入解析该区域的造山与剥蚀演化历史，具体包括碎屑锆石U-Pb定年、对部分经U-Pb定年的锆石开展（U-Th）/He热年代学分析，以及碎屑角闪石、云母与长石的Ar-Ar氩氩定年。
更广泛影响力：本研究将培养印第安纳大学-普渡大学印第安纳波利斯分校（Indiana University–Purdue University Indianapolis, IUPUI）的1名理学硕士研究生、哥伦比亚大学（Columbia）的1名博士研究生，以及两所院校的多名本科生。参与项目的研究生将参与指导本科生科研工作。研究成果将以适配教学层级的具体案例与习题形式融入课堂教学。Licht与哥伦比亚大学研究生E. Pierce正与当地中学教师合作开发外展项目，引导师生探究本地冰川物质的物源特征。本研究成果对众多研究领域均具有广泛应用价值。