COLLABORATIVE RESEARCH: Thickness, Extent and Basal Conditions the Scandinavian Ice Sheet Around the Last Glacial Maximum

摘要：美国威斯康星大学麦迪逊分校地质与地球物理系David M. Mickelson和Paul Cutler合作项目：末次极大期前后斯堪的纳维亚冰盖的厚度、范围和基础条件（提案号：0087369）。我们将重建斯堪的纳维亚冰盖（SIS）从~32 ka到~10 ka的厚度、范围和冰下环境。该研究将考虑四个仍有争议的方面：第一，末次盛冰期（LGM）的冰盖厚度是多少，挪威西部是否存在无冰区？第二，从物理上讲，将冰盖中心部分的地貌证据解释为在大部分冰川时期都是一个以冷为基础的冰盖是否合理？第三，21千年时俄罗斯冰原东部边缘的范围是多少？ 21千年时没有地貌证据，但却是GCM模拟过去气候的关键时期。第四，气候和内部循环对调节冰动力学的相对贡献是什么？ SIS在全球范围内的作用是什么？为了回答这些问题，我们将把精力集中在SIS的两个关键区域（挪威西部和从挪威北部向东进入俄罗斯的样带），在那里我们将收集样品进行预固结测试和宇宙起源年代测定。野外工作的结果以及其他可用的地质和气候数据将被纳入一个二维的、随时间变化的流带冰盖模型。

ABSTRACTA collaborative project: Thickness, Extent, and Basal Conditions of the Scandinavian Ice SheetAround the Last Glacial Maximum(Proposal Nr. 0087369)by David M. Mickelson and Paul Cutler (Department of Geology and Geophysics, University of Wisconsin-Madison)We will reconstruct the thickness, extent, and subglacial environment of the Scandinavian Ice Sheet (SIS) from ~32 ka to ~10 ka. Four still controversial aspects will be considered in the study: First, what was the thickness of the ice sheet at the last glacial maximum (LGM), and did ice-free regions exist in western Norway? Second, is it physically reasonable to interpret geomorphic evidence from the central parts of the ice sheet as indicating a cold-based ice sheet through most of glacial time? Third, what was the extent of the eastern margin of the ice sheet in Russia at 21 ka - a time for which no geomorphic evidence exists, but a key time in GCM simulations of past climates. Fourth, what were the relative contributions of climate and internal cycles to regulating ice dynamics, and what was the role of the SIS in a global context?To answer these questions, we will focus our efforts on two key regions of the SIS (western Norway, and a transect from northern Norway eastwards into Russia) where we will collect samples for preconsolidation tests and cosmogenic dating. The results from field work as well as other available geologic and climate data will be incorporated into a two-dimensional, time-dependent flowband ice-sheet model.