Collaborative Research: Late Quaternary Glaciations of Northern Novaya Zemlya, Russia

欧亚大陆北部更新世冰盖的范围和时间仍然悬而未决。这些观点从海洋冰盖对巴伦支海和喀拉海的全面覆盖到邻近群岛上的陆基冰盖系统，不一而足。在欧亚北部最后一次冰川的性质上，分歧的核心是新泽利亚和延伸到西伯利亚的冰盖厚度的不确定性。与摩尔曼斯克海洋生物研究所合作，我们建议启动基本的冰川地质、地层和地质年代学研究，以提供新的现场数据，以独立评估俄罗斯Novaya Zemlya上魏克斯勒冰川和去冰川事件的界限和时间。实地研究将集中在Novaya Zemlya北部的三个领域，那里的无冰前地包含丰富的凸起的海洋和冰川特征。我们计划使用以下方法来破译Novaya Zemlya上的第四纪冰川记录：1)将使用高分辨率(10-m像素)SPOT卫星图像来评估在野外可能难以辨别的大尺度海平面、冰川侵蚀和沉积特征(冰川)。2)通过对已知海拔的隆起海滩中的亚化石进行放射性碳测年，记录冰川均衡响应的时间和速率。3)悬崖段叠置第四系沉积的地层学和沉积学研究。将特别注意冰川损害和不整合的识别，以及为古环境评估和年代学控制收集微型和宏观动物。冰川碎屑的来源研究和组构分析应能为冰川源区提供新的信息。4)最新冰川/海平面事件的年龄控制将由包括海洋亚化石和漂流的常规和AMS放射性碳测年得出。较老事件的数量和时间将受到使用L异亮氨酸/D-异亮氨酸比率和更高分辨率的D/L天冬氨酸比率进行软体动物氨基酸异构化分析的限制。数值年龄将通过对潮下隆起沉积物的细粒组分(4-11(M))的发光测年来确定。5)将现场数据与均衡和冰川学模拟相结合，以深入了解冰川厚度、冰分、穹顶和溪流的位置以及对海平面上升的反应。这项研究的结果对于评估北部大陆架上的冰盖是否在14ka前巴伦支海、喀拉海和挪威海消融以及欧亚冰盖对北大西洋温盐环流的影响是否同步响应具有重要意义。这项实地研究将提供有关俄罗斯北极魏氏冰川几何的新数据，该地区目前几乎不存在冰川，这是不断演变的全球气候模型的关键边界条件。

The extent and timing of Pleistocene ice sheets over northern Eurasia remain unresolved. The views range from full coverage of the Barents and Kara Seas by a marine-based ice sheet to land-based ice-cap systems on adjacent archipelagos. The heart of the divergence on the nature of last glaciation in northern Eurasian is uncertainty on ice sheet thickness over Novaya Zemlya and extension into Siberia. In collaboration with the Murmansk Institute of Marine Biology we propose to initiate basic glacial-geologic, stratigraphic and geochronologic studies to provide new field data to independently evaluate the limits and timing of Weichselian glacial and deglacial events on Novaya Zemlya, Russia. Field research will focus on three field areas on northern Novaya Zemlya, where ice-free forelands contain abundant raised marine and glacial features. We plan to use the following approaches to decipher the record of Quaternary glaciations on Novaya Zemlya: 1) High resolution (10-m pixels) SPOT satellite imagery will be used to evaluate large scale sea-level, glacial erosional and depositional features (moraines) that may not readily be discernible in the field. 2) Documentation of the timing and rate of the glacial-isostatic response by radiocarbon dating of subfossils included in raised beaches of known elevation. 3) A study of the stratigraphy and sedimentology of superimposed Quaternary sediments in cliff sections. Particular attention will be given to the recognition of glacial damicts and unconformities, and the collection of micro-and macro-fauna for paleoenvironmental assessment and chronologice control. Provenance studies of clasts from glacial diamicts and fabric analysis should provide new information on glacial source area. 4) Age control for the latest glacial/sea level events will be derived from conventional and AMS radiocarbon dating of included marine subfossil and driftage. The number and timing of older events will be constrained by amino acid epimerization analyses of mollusks using L-isoleucine/D-alloisoleucine ratios and higher resolution D/L aspartic acid ratios. Numeric age will be determined by luminescence geochronometry on the fine-grained fraction (4-11(m) from raised sublittoral sediments. 5) Integration of field data with isostatic and glaciological modeling to provide insight into glacier thickness, position of ice divides, domes and streams and response to sea level rise. Results from this study are important for evaluating if ice sheets on northern continental shelves responded synchronously, if the Barents, Kara and Norwegian Seas deglaciated prior to 14 ka ago, and the effect of Eurasian ice sheets on North Atlantic thermohaline circulation. This field-based research will provide new data on Weichselian glacier geometry in the Russian Arctic, where little currently exists, which is a critical boundary condition for evolving global climate models.