CNRS-INSU Glacial erosion project

***Dating and measuring glacial erosion : potential and limitations of cosmogenic nuclides in situ

The main objective of this study is to better understand glacial dynamics at the Quaternary scale in terms of erosion and transport processes, and to be able to quantify its impact on the landscape. The "unpredictability" of glacier action in relation to other landscape shaping agents and the long times (102-104 years) of this action make any quantification very difficult at the scale of modern/historical observations. We are therefore interested in the recording of these processes by geomorphological objects on the time scale of one or even several glaciations using cosmogenic nuclides with adapted half-life times.

The questions we ask ourselves are the following : do the tills transported on the bottom have a highly abrasive action or do they play a protective role for the substratum ? Can a polished surface be glazed/dislaid without being eroded ? Are most glacial sediments produced ex novo at each glaciation or is there a significant component of reworking old moraines and other periglacial formations ? All these aspects are of crucial importance for erosive balances at the scale of a catchment area or even a mountain range. They are also a determining point for dating the shapes of the glacial and periglacial relief as morphological markers.