Abstract Glacial erosion has shaped many mountain belts during the cold periods of the Late Cenozoic. The rate of glacial erosion is sensitive to the subglacial environment, including both the subglacial hydrology and the basal thermal regime. Geothermal heat from underlying bedrock is a major contributor to glacier energy budgets, controlling ice dynamics at the ice-bed interface by changing the basal temperature and the supply of meltwater. Despite the known influence of geothermal heat on the subglacial environment, its impact on glacial erosion has received little study. The geothermal heat flux in glaciated mountain ranges varies widely as a function of the tectonic setting. Therefore, if glacial erosion is sensitive to geothermal heat flux, the evolution of glaciated landscapes may depend upon tectonically-controlled geothermal gradients. We explore the impact of geothermal heat flux on the rates and spatial patterns of glacial erosion in mountain ranges using numerical models. We couple a sliding-dependent glacial erosion model with the Parallel Ice Sheet Model (PISM) to simulate the evolution of a synthetic glacial landscape. We find a robust tendency for increasing glacial erosion with increasing geothermal heat flux. The spatial pattern of erosion also varies with the magnitude of geothermal heat flux. At low geothermal heat flux, glacial erosion is consistently focused in major valleys. As geothermal heat flux increases, the area of significant glacial erosion expands into higher elevations and the rate of erosion increases. The location of maximum erosion migrates up-valley as geothermal heat flux increases, suggesting that glacial erosion tends to produce distinct landscapes as a function of geothermal heat flux. Our finding suggests that active mountain belts with high geothermal heat flux will express the glacial buzzsaw effect, in which high elevation topography is preferentially removed by glacial erosion. Glaciers at passive margins with low geothermal heat flux, in contrast, will tend to incise deep valleys at relatively low elevations. Previous work on the interaction between tectonics and landscape evolution has focused on relief generation and fracturing of rocks. Our results introduce a novel potential linkage between tectonics and erosion based on the sensitivity of glacial erosion to geothermal heat.

中文翻译：

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通过地热热通量对冰川侵蚀速率和空间格局的构造控制

摘要 晚新生代寒冷时期冰川侵蚀形成了许多山带。冰川侵蚀的速率对冰下环境敏感，包括冰下水文和基础热状况。来自底层基岩的地热是冰川能量收支的主要贡献者，通过改变基础温度和融水供应来控制冰床界面的冰动态。尽管已知地热对冰下环境有影响，但其对冰川侵蚀的影响却鲜有研究。作为构造环境的函数，冰川山脉中的地热热通量变化很大。因此，如果冰川侵蚀对地热热通量敏感，冰川景观的演变可能取决于构造控制的地温梯度。我们使用数值模型探索地热热通量对山脉冰川侵蚀速率和空间格局的影响。我们将滑动依赖的冰川侵蚀模型与平行冰盖模型 (PISM) 结合起来，以模拟合成冰川景观的演变。我们发现随着地热热通量的增加，冰川侵蚀呈现出强烈的趋势。侵蚀的空间格局也随着地热热通量的大小而变化。在低地热热通量下，冰川侵蚀始终集中在主要山谷中。随着地热热通量的增加，冰川侵蚀显着的区域扩展到更高的海拔，侵蚀速率增加。随着地热热通量的增加，最大侵蚀的位置向上迁移，表明冰川侵蚀往往会产生不同的景观作为地热热通量的函数。我们的发现表明，具有高地热热通量的活动山带将表现出冰川锯齿效应，其中高海拔地形被冰川侵蚀优先去除。相比之下，地热热通量低的被动边缘冰川往往会在相对较低的海拔处切割出深谷。先前关于构造与景观演化之间相互作用的工作主要集中在岩石的浮雕生成和破裂上。我们的结果基于冰川侵蚀对地热的敏感性，在构造和侵蚀之间引入了一种新的潜在联系。我们的发现表明，具有高地热热通量的活动山带将表现出冰川锯齿效应，其中高海拔地形被冰川侵蚀优先去除。相比之下，地热热通量低的被动边缘冰川往往会在相对较低的海拔处切割出深谷。先前关于构造与景观演化之间相互作用的工作主要集中在岩石的浮雕生成和破裂上。我们的结果基于冰川侵蚀对地热的敏感性，在构造和侵蚀之间引入了一种新的潜在联系。我们的发现表明，具有高地热热通量的活动山带将表现出冰川锯齿效应，其中高海拔地形被冰川侵蚀优先去除。相比之下，地热热通量低的被动边缘冰川往往会在相对较低的海拔处切割出深谷。先前关于构造与景观演化之间相互作用的工作主要集中在岩石的浮雕生成和破裂上。我们的结果基于冰川侵蚀对地热的敏感性，在构造和侵蚀之间引入了一种新的潜在联系。先前关于构造与景观演化之间相互作用的工作主要集中在岩石的浮雕生成和破裂上。我们的结果基于冰川侵蚀对地热的敏感性，在构造和侵蚀之间引入了一种新的潜在联系。先前关于构造与景观演化之间相互作用的工作主要集中在岩石的浮雕生成和破裂上。我们的结果基于冰川侵蚀对地热的敏感性，在构造和侵蚀之间引入了一种新的潜在联系。