Glacial erosion produces vast quantities of fine-grained sediment that has a far-reaching impact on Earth surface processes. To gain a better understanding of the production of glacial silt and clay, we use automated mineralogy to quantify the microstructure and mineralogy of rock and sediment samples from 20 basins in the St. Elias Mountains, Yukon, Canada. Sediments were collected from proglacial streams, while rock samples were collected from ice marginal outcrops and fragmented using electrical pulse disaggregation. For both rock fragments and sediments, we observe a log-normal distribution of grain sizes and a sub-micrometer terminal grain size. We find that the abrasion of silt and clay results in both rounding and the exploitation of through-going fractures. The abundance of inter- versus intragranular fractures depends on mineralogy and size. Unlike the relatively larger grains, where crushing and abrasion are thought to exploit and produce discrete populations of grain sizes, the comminution of fines leads to a grain size, composition and rounding that is continuously distributed across size, and highly dependent on source-rock properties.

中文翻译：

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使用自动矿物学表征冰川淤泥和粘土

冰川侵蚀产生大量细粒沉积物，对地球表面过程产生深远影响。为了更好地了解冰川淤泥和粘土的产生，我们使用自动化矿物学来量化加拿大育空地区圣埃利亚斯山脉 20 个盆地的岩石和沉积物样品的微观结构和矿物学。沉积物是从前冰川流中收集的，而岩石样本是从冰边缘露头中收集的，并使用电脉冲分解进行破碎。对于岩石碎片和沉积物，我们观察到粒度的对数正态分布和亚微米终端粒度。我们发现淤泥和粘土的磨损导致了圆形和贯穿裂缝的开采。粒间裂缝与粒内裂缝的丰度取决于矿物学和尺寸。与相对较大的颗粒不同，其中破碎和磨损被认为是利用和产生离散的颗粒尺寸群，细粉的粉碎导致颗粒尺寸、成分和圆度在尺寸上连续分布，并且高度依赖于烃源岩特性.