Illgraben bedrock erosion samples

Erosion marks on marble and granite bed samples in the Illgraben Torrent (2006-2007). When studying bedrock erosion by a debris flows event, rarely do we know the detailed initial topography of the bedrock channel. This makes it impossible to measure the volume loss due to single debris flow events. To overcome this challenge, we placed initially flat stone samples of marble and granite in the Illgraben torrent, Switzerland, a location frequently scoured by natural debris flows. At the Illgraben, there are typically several events per year, due to the high availability of source material in the upper catchment that fail during summer rain storms (e.g. McArdell et al., 2007; Badoux et al., 2009, Berger, 2011). The stone samples captured groove and impact marks on the stone samples caused by the debris flows.

2006-2007年，伊尔格拉本溪（Illgraben Torrent）内大理石与花岗岩床面样品的侵蚀痕迹。在研究泥石流事件对基岩的侵蚀作用时，我们往往难以获取基岩河道的精确初始地形，因此无法量化单次泥石流事件导致的体积损失量。为解决这一难题，我们将初始平整的大理石与花岗岩样品放置于瑞士伊尔格拉本溪中——该区域因频繁发生自然泥石流而被长期冲刷。伊尔格拉本溪每年通常会发生多次泥石流事件，这是因为上游集水区内存在大量松散物源，在夏季暴雨期间极易发生失稳垮塌（例如McArdell等人，2007年；Badoux等人，2009年；Berger，2011年）。这些石材样品记录了泥石流作用在其表面形成的刻槽与撞击痕迹。