Ice Sheet Configuration and Erosion Patterns in the Northern Swedish Mountains from Cosmogenic Radionuclides

对山区冰盖开始和衰减的不现实模拟、重建冰面剖面的不确定性以及普遍未能考虑冰盖下景观发展，都是冰盖模式在气候研究中成功使用的主要限制因素。例如，边线和风化差异被解释为以前冰盖高度的指标，但最近在斯堪的纳维亚的绘图表明，这些特征可能反映了湿（暖）基侵蚀冰和干（冷）基非侵蚀冰之间的内部热边界，导致对冰盖厚度和高度的解释非常不同。首席调查员将试图解决芬诺斯坎德冰盖部分地区冰川地貌的相互矛盾的解释。地貌和地层学证据表明，挪威-瑞典山脉是了解芬诺斯坎德冰盖形成和衰变的重要区域。该山脉的冰川形态反映了过去600万年中不同时期、不同强度的环状冰川、山谷冰川和冰盖侵蚀。保存最古老的地表是一个潜在的参考视界，根据它可以计算冰川侵蚀，以增强我们对冰盖动力学的理解。这是加强冰川循环模式模拟的关键基础，它将检验一般环流模式在预测气候方面的作用。这项工作将通过测量从不同的、最近绘制的地貌区域的岩石表面收集的样品中的多种宇宙形成放射性核素来完成。这些结果将检验现有的关于冰盖结构的假设，并为关于“冰期前”表面的年龄的争论提供新的信息，这些表面似乎在反复的冰盖覆盖中幸存下来。将研究魏奇塞利冰盖的高度和芬诺斯坎德冰盖的基础热状态和相关冰川侵蚀的空间格局。对景观发展和基础热状态的洞察将为瑞典科学家正在进行的芬诺斯坎德冰盖建模提供新的边界条件。首席研究人员将实地测试地表是否经历了长时间的冰埋藏，并使用宇宙生成放射性核素的新应用。为了取得成功，首席调查员将从不同类型的冰川历史景观中收集样本。瑞典自然科学研究委员会资助了首席研究员的瑞典同行进行类似的工作，这两个小组将在这个项目上合作。识别合适的景观特征依赖于高质量的山地地貌测绘，这是斯德哥尔摩大学古冰川学小组的主要专业领域。普渡大学的设施和设施将提供冰川地貌学和宇宙生成放射性核素技术应用方面的专业知识和分析能力。

Unrealistic simulation of ice sheet inception and decay in mountainous regions, uncertainties in reconstructing ice surface profiles, and common failure to consider landscape development under ice sheets all contribute to major limitations for successful use of ice sheet models in climate research. For example, trimlines and weathering differences have been interpreted as indicators of former ice sheet height, but recent mapping in Scandinavia suggests that such features may reflect internal thermal boundaries between wet-(warm)-based erosive ice and dry-(cold) based-non-erosive ice, leading to very different interpretations of ice sheet thickness and height. The Principal Investigators will attempt to resolve conflicting glacial landform interpretations for parts of the Fennoscandian ice sheet. Geomorphologic and stratigraphic evidence indicates the Norwegian-Swedish mountains are an important area for understanding Fennoscandian ice sheet inception and decay. Glacial morphology in this mountain range reflects cirque glacier, valley glacier, and ice sheet erosion at different times and with various intensities over the past six million years. The oldest preserved surface is a potential reference horizon against which glacial erosion can be computed to enhance our understanding of ice sheet dynamics. This is critical groundwork for enhanced model simulations of the glacial cycle, which would test for general circulation models in predicting climate.This work will be accomplished by measuring multiple cosmogenic radionuclides in samples collected from rock surfaces in distinct, recently mapped, geomorphic regions. The results will test existing hypotheses of ice sheet configuration and provide new information for debates over the age of "preglacial" surfaces that appear to have survived repeated ice sheet overriding. The height of the Weichselian ice sheet and the spatial patterns of basal thermal regimes and associated glacial erosion of the Fennoscandian ice sheet will be studied. Insight into landscape development and basal thermal regimes will provide new boundary conditions for Fennoscandian ice sheet modeling being undertaken by Swedish scientists. The Principal Investigators will field test whether a surface has experienced lengthy ice burial with a new application of cosmogenic radionuclides. To be successful, the Principal Investigators will collect samples from sites within landscapes of different types of glacial histories. The Swedish Natural Science Research Council has funded the Principal Investigators' Swedish counterparts for similar work and the two groups will work collaboratively on this project. Recognition of suitable landscape features relies on high quality mapping of mountain geomorphology which is a primary area of expertise of the Paleoglaciology Group at the University of Stockholm. Purdue University facility and facilities will provide expertise and analytical capabilities in glacial geomorphology and applications of cosmogenic radionuclide techniques.