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

9909686 BergThe Arctic是一个对未来全球气候变化高度敏感的地区，然而它的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，北极的中西伯利亚地区基本上是未开发的。 德国和俄罗斯科学家在过去6年中对泰梅尔半岛至北极岛屿Severnaya Zemlya进行了地质、地球化学和地球物理研究，研究范围为南北向1400公里长的样带。 他们的目标是解开中西伯利亚北方在过去数万年里的气候和环境历史。 已经从几个现有的湖泊中回收了长（高达-22米）的沉积物岩心，为整个项目提供了最重要的古环境数据档案，但它们已经被证明很难或不可能通过各种放射性碳程序来确定日期，主要是因为碳浓度非常低，或者存在污染的煤颗粒。 PI建议提供一种替代的测年工具：对沉积物颗粒最后一次暴露于日光的情况进行红外激发发光直接测年。 根据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。 PI将首先从波茨坦（德国）的湖芯储存地点采集样本（单独供资）。 所提出的发光方法在其他地方也被证明是准确的，而且沉积物的年龄比西伯利亚湖芯中预期的要大得多。 发光日期预计将提供第一个直接的，准确的年表，这些湖芯，因此，时间序列的几个古环境数据集已经测量的德国同事。 这些日期也应该解决了关于北极西伯利亚中部地区最后一个冰盖（欧亚冰盖）的大小（范围）的争议。 一些湖芯中存在冰川沉积物，但这些沉积物的年龄目前尚不清楚或高度推测。 预计测年结果也将提供第一次机会，跨北冰洋相关的第四纪花粉地层从阿拉斯加，PI一直参与。 环北极地区第四纪沉积物古环境记录的准确时间序列对于更全面（定量）了解北极过去在全球变化中的作用至关重要。

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.