Reconstructing the evolution of ice sheets is critical to our understanding of the global environmental system, but most detailed palaeo-glaciological reconstructions have hitherto focused on the very recent history of ice sheets. Here, we present a three-dimensional (3D) reconstruction of the changing nature of ice-sheet derived sedimentary architecture through the Quaternary Ice Age of almost 3 Ma. An extensive geophysical record documents a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the mid-Norwegian shelf since the beginning of the Quaternary. Spatial and temporal variability of the FIS is illustrated by the gradual development of fast-flowing ice streams and associated intensification of focused glacial erosion and sedimentation since that time. Buried subglacial landforms reveal a complex and dynamic ice sheet, with converging palaeo-ice streams and several flow-switching events that may reflect major changes in topography and basal thermal regime. Lack of major subglacial meltwater channels suggests a largely distributed drainage system beneath the marine-terminating part of the FIS. This palaeo-environmental examination of the FIS provides a useful framework for ice-sheet modelling and shows that fragmentary preservation of buried surfaces and variability of ice-sheet dynamics should be taken into account when reconstructing glacial history from spatially limited datasets.

中文翻译：

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从 3D 地震数据推断的挪威中部大陆边缘第四纪冰盖动力学

重建冰盖的演变对于我们理解全球环境系统至关重要，但迄今为止，最详细的古冰川学重建都集中在冰盖的最近历史上。在这里，我们展示了通过近 3 Ma 的第四纪冰河时代冰盖衍生沉积结构的变化性质的三维 (3D) 重建。广泛的地球物理记录记录了自第四纪开始以来挪威中部大陆架上周期性出现的海洋终止、产犊 Fennoscandian 冰盖 (FIS) 边缘。从那时起，快速流动的冰流的逐渐发展以及相关的集中冰川侵蚀和沉积的加剧说明了 FIS 的时空变化。掩埋的冰下地貌揭示了一个复杂而动态的冰盖，具有汇聚的古冰流和几个可能反映地形和基础热状况的重大变化的流动切换事件。缺乏主要的冰下融水通道表明 FIS 海洋终止部分下方有一个主要分布的排水系统。FIS 的这种古环境检查为冰盖建模提供了一个有用的框架，并表明在从空间有限的数据集重建冰川历史时，应考虑掩埋表面的零碎保存和冰盖动力学的可变性。缺乏主要的冰下融水通道表明 FIS 海洋终止部分下方有一个主要分布的排水系统。FIS 的这种古环境检查为冰盖建模提供了一个有用的框架，并表明在从空间有限的数据集重建冰川历史时，应考虑掩埋表面的零碎保存和冰盖动力学的可变性。缺乏主要的冰下融水通道表明 FIS 海洋终止部分下方有一个主要分布的排水系统。FIS 的这种古环境检查为冰盖建模提供了一个有用的框架，并表明在从空间有限的数据集重建冰川历史时，应考虑掩埋表面的零碎保存和冰盖动力学的可变性。