History of Quaternary Ice Sheets on Arctic Islands, Phase 1: Integrated Approach Using Dating of Terrestrial Glacial Deposits, Glacially Abraded Bedrock and Marine Shorelines

末次冰期北极冰盖范围是北极冰川地质学、古冰川学和古气候学中最具争议的问题之一。其中一个主要原因是我们无法准确地确定确定古代冰缘的陆地沉积物的年代。宇宙核素的原位积累可以用来解决这个问题。在这项研究中，宇宙表面暴露测年方法将用于重建最后北极冰盖的历史。提出的综合研究的主要目标是提供支持或反对晚第四纪因纽特冰原存在的明确证据，重建最后一次冰原从诞生到今天的历史，并确定最后一次冰期开始前无冰期的持续时间。此次调查将获得格陵兰岛西北部、埃尔斯米尔岛东部和它们之间的几个小岛、埃尔斯米尔岛西部和阿克塞尔海伯格岛东部、德文岛、巴芬岛、康沃利斯岛、萨默塞特岛、巴瑟斯特岛、帕特里克王子岛和埃尔夫林尼斯岛的冰川沉积物和抛光基岩的宇宙成因地表暴露年龄。他们还将获得隆起的海洋海岸线的宇宙成因和放射性碳年龄，以便重建这些地点的海平面变化历史。研究结果将为北极岛屿晚第四纪冰期提供急需的年代学控制。这些结果也将对古气候学研究产生重要影响，因为有可能确定在最后一次冰期期间北冰洋和巴芬湾之间是否存在联系。

The extent of arctic ice sheets during the last glaciation is among the most controversial issues in arctic glacial geology, paleoglaciology and paleoclimatology. One of the main reasons is our inability to accurately date terrestrial deposits that define ancient ice margins. The in situ accumulation of cosmogenic nuclides can be used to approach this problem. In this study, cosmogenic surface exposure dating methods will be used to reconstruct the history of the last arctic ice sheets. The main goals of the proposed integrated study are to provide clear evidence either for or against the existence of the Innuitian Ice Sheet in the late Quaternary, to reconstruct the history of the last ice sheets, from their birth until today, and to determine the duration of ice-free period before the last glaciation started. The investigation will obtain cosmogenic surface exposure ages for glacial deposits and polished bedrock in northwestern Greenland, eastern Ellesmere Island and several small islands between them, western Ellesmere and eastern Axel Heiberg islands, Devon, Baffin, Cornwallis, Somerset, Bathurst, Prince Patrick and Ellef Ringness islands. They will also obtain cosmogenic and radiocarbon ages for raised marine shorelines in order to reconstruct the history of sea level changes at these locations. The results will provide the much needed chronologic control for the late Quaternary glaciations in arctic islands. The results will also have important implications for paleoclimatologic studies because of a possibility to establish whether or not there was a connection between the Arctic Ocean and Baffin Bay during the last glaciation.