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

上一次冰川期间北极冰盖的范围是北极冰川地质学、古冰川学和古气候学中最有争议的问题之一。其中一个主要原因是我们无法准确地确定定义古代冰缘的陆地沉积物的年代。宇宙成因核素的原位积累可以用来解决这个问题。在这项研究中，宇宙成因的表面暴露测年方法将被用来重建最后一次北极冰盖的历史。拟议的综合研究的主要目标是提供明确的证据，支持或反对第四纪晚期因努伊特冰盖的存在，重建最后一次冰盖从它们诞生到今天的历史，并确定最后一次冰川开始之前的无冰期的持续时间。这项调查将获得格陵兰西北部、埃尔斯米尔岛东部和它们之间的几个小岛、西部埃尔斯米尔岛和东部阿克塞尔海贝格岛、德文岛、巴芬、康沃利斯、萨默塞特、巴瑟斯特、帕特里克王子和埃尔夫·林斯岛的冰川沉积物和抛光基岩的宇宙表面暴露年龄。他们还将获得升高的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。这一结果将为北极岛屿晚第四纪冰川提供急需的年代学控制。这一结果还将对古气候学研究产生重要影响，因为有可能确定北冰洋和巴芬湾在上一次冰川期间是否存在联系。

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.