Luminescence Timing of Paleoenvironmental Changes in Quaternary Lake Sediments from the Arctic Taymyr Peninsula, Siberia

据预测，北极是一个对未来全球气候变化高度敏感的地区，但其严酷和偏远限制了我们对该地区过去气候/环境变化的地质记录的了解。在这方面，北极的西伯利亚中部地区基本上还没有被勘探过。在过去的6年里，德国和俄罗斯科学家对从泰米尔半岛到南北交线长1400公里的北极岛屿塞维纳亚·泽姆利亚进行了地质、地球化学和地球物理研究。他们的目标是揭开西伯利亚中部北部几万年来的气候和环境历史。从几个现有湖泊中恢复了长达-22米的沉积物岩心，提供了整个项目最重要的古环境数据档案，但通过各种放射性碳程序证明，这些岩心很难或不可能确定日期，主要是因为碳浓度很低，或者存在受污染的煤粒。PI建议提供另一种测年工具：对最后一次暴露在日光下的沉积物颗粒进行红外激发发光直接测年。基于对阿拉斯加和其他北美湖芯的丰富经验，PI将在NSF的支持下在里诺分析大约29个湖芯样本。样本将首先由PI从德国波茨坦的一个湖心存储地点收集(在单独的资金支持下)。建议的发光方法在其他地方被证明是准确的，而且沉积物的年龄比西伯利亚湖芯预期的要老得多。发光日期有望为这些湖芯提供第一个直接、准确的年代学，从而为德国同事已经测量的几个古环境数据集的时间序列提供时间序列。这些日期也应该解决关于北极西伯利亚中部地区最后一次冰盖(欧亚冰盖)的大小(范围)的争议。在一些湖芯中存在冰川沉积物，但目前这种沉积物的年龄尚不清楚，或者说是高度推测的。测年结果也有望为跨北冰洋与阿拉斯加第四纪孢粉地层对比提供第一次机会，PI一直参与其中。来自环北极第四纪沉积物的准确的古环境记录时间序列对于更全面地(定量)了解北极过去在全球变化中的作用是必不可少的。

9909686BergThe arctic is a predicted highly sensitive region to future global climatic change, yet its harshness and remoteness have limited our knowledge of the geological record of past climatic/environmental changes in this region. The region of arctic Central Siberia is largely unexplored in this regard. German and Russian scientists have conducted geological, geochemical and geophysical studies over the last 6 years from the Taymyr Peninsula to the arctic islands of Severnaya Zemlya, on a south-north transect -1400 km long. Their objective has been to unravel the climatic and environmental history of northern Central Siberia over the last several tens of thousands of years. Long (up to -22 m) sediment cores have been recovered from several existing lakes, providing the most important paleoenvironmental data archive of the entire project, but they have proven to be difficult or impossible to date by the various radiocarbon procedures, mainly because of very low carbon concentration, or the presence of contaminating coal particles. The PI proposes to provide an alternative dating tool: infrared-stimulated-luminescence direct dating of the last exposure of sediment grains to daylight. Based on extensive experience with Alaskan and other North American lake cores, the PI will analyze in Reno about 29 lake-core samples with NSF support. Samples will first be collected (under separate funding) by the PI from a lake-core storage site in Potsdam, Germany. The proposed luminescence method has been shown to be accurate elsewhere, and with sediments much older than those expected in the Siberian lake cores. Luminescence dates are expected to provide the first direct, accurate chronology for these lake cores, and hence for the time series of several paleoenvironmental data sets already measured by German colleagues. These dates should also settle a controversy about the size (extent) of the last ice sheet (Eurasian Ice Sheet) in the area of central arctic Siberia. Glacial sediments are present in some of the lake cores, but the age of such sediments is unknown or highly speculative at present. Dating results are expected to provide also the first opportunity for across-Arctic-Ocean correlation to Quaternary pollen stratigraphies from Alaska that the PI has been involved with. Accurate time series of paleoenvironmental records from circum-arctic Quaternary sediments are essential for a fuller (quantitative) understanding of the past role of the arctic in global changes.