Glacial Erosion and the Budget of Basal Rock Debris

研究控制冰块底部岩石碎片丰度和分布的过程具有相当大的动机，因为它们在冰川和冰盖的动力学和地貌表现中占有重要地位。拟议的工作旨在更好地了解侵蚀过程如何在冰川床上产生和改变碎片，以及运输过程如何混合，分散并最终消除这些碎片。研究人员将完成一个冰川采石的理论模型，并改进一个新的磨损模型，这将首次在控制基岩侵蚀和大量基底碎片的所有主要过程之间提供定量联系。然后，有了关于从床上采石的碎屑和颗粒/床相互作用的新模型结果，就有可能重新分析大量关于冰川漂移的已发表数据，包括分散模式、颗粒尺寸的空间变化以及反映磨损和断裂的颗粒纹理。从这些模型中获得的物理洞察和量化将为冰川碎片的起源提供重要的新线索，并对冰盖和冰川底部未石化物质的行为做出比以前更精确的推断。拟议的研究是由ERA87-08400资助的、已接近完成的大规模冰川侵蚀研究的自然延伸。该研究为我们提出的侵蚀分析的改进及其在冰川沉积物关键特征的冰川学解释中的应用提供了坚实的基础。

Considerable motivation exists to study processes that govern the abundance and distribution of rock debris at the base of ice masses because they figure importantly in the dynamics and geomorphic manifestations of glaciers and ice sheets. The proposed work is aimed at better understanding how erosional processes operate to generate and modify debris at the glacier bed, and how transport processes mix, disperse and eventually eliminate this debris. Researchers will complete a theoretical model of glacial quarrying and refine a new model of abrasion, which provides for the first time a quantitative link between all major processes governing both the erosion of bedrock and the abundance of basal debris. Then, armed with new model results about quarrying of debris from the bed and particle/bed interactions, it is possible to re-analyse considerable published data on glacial drift, including dispersal patterns, spatial variations in grain size, and particle textures reflecting wear and fracture. The physical insight and quantification gained from the models will shed significant new light on the genesis of glacial debris, and lead to more precise inferences about the behavior of unlithified material at the base of ice sheets and glaciers than has been previously possible. The proposed research is a natural extension of the work nearly completed on large-scale glacial erosion, with funds from ERA87-08400. This study provides a firm foundation for the proposed refinement of our erosion analysis, and its application to the glaciological interpretation of key characteristics of glacial sediments.