The geology beneath Thwaites Glacier, the Antarctic glacial catchment most vulnerable to climate change, is unknown. Thwaites Glacier lies within the West Antarctic Rift System, but details of the subglacial geology relevant to glacial flow, including sediment availability, underlying lithology, and heat flux, are lacking. We present the first sketch map of the subglacial geology of Thwaites Glacier, interpreted from maps of airborne gravity, magnetic and radar data, supported by 2D models and 3D inversion of subsurface properties, and the regional geological context. A zone of Cretaceous mafic magmatism extending ~200 km inland from the coast is interpreted, while sedimentary basins are restricted to a region 150 to 200 km inboard of the coast, underlying just 20% of the catchment. Several granitic subglacial highlands are identified, forming long-lived topographic highs. Our geological interpretation places constraints on the basal properties of Thwaites Glacier, laying the foundation for both improved predictions of ice sheet change and studies of West Antarctic tectonics.

中文翻译：

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地质示意图以及综合航空地球物理观测对南极洲西部思韦茨冰川冰流的影响

思韦茨冰川是最容易受到气候变化影响的南极冰川流域，其下方的地质情况尚不清楚。思韦茨冰川位于南极洲西部裂谷系统内，但缺乏与冰川流相关的冰下地质细节，包括沉积物可用性、底层岩性和热通量。我们展示了第一个 Thwaites 冰川冰下地质示意图，该示意图是根据机载重力、磁力和雷达数据图进行解释的，并得到 2D 模型和地下属性 3D 反演以及区域地质背景的支持。解释了从海岸向内陆延伸约 200 公里的白垩纪镁铁质岩浆作用区，而沉积盆地仅限于海岸内侧 150 至 200 公里的区域，仅覆盖流域的 20%。发现了几个花岗岩冰下高地，形成了长期存在的地形高地。我们的地质解释对思韦茨冰川的基本特性施加了限制，为改进冰盖变化预测和西南极构造研究奠定了基础。