Geomorphic Response To The Lateglacial-Holocene Transition In High Alpine Regions (Sanetsch Pass, Swiss Alps)

Several palaeoclimatic archives have documented the pronounced climatic and environmental change associated with the Lateglacial-Holocene transition in the European Alps. However, the geomorphic response to this major environmental transition has only been punctually investigated. In this study, we propose a detailed reconstruction of post-Last Glacial Maximum palaeoenvironmental conditions and geomorphic connectivity in the Sanetsch Pass area (2252 m a.s.l., western Swiss Alps) based on a multi-method approach combining geomorphological and sedimentological field investigations with quantitative sedimentology and geochronology. Samples for sediment characterization (grain size, micromorphology and X-ray diffraction) and geochronology (optically stimulated luminescence and Be-10 surface exposure dating) were collected from three representative landforms of the study area: a high-elevation silty deposit covered by patterned ground, an alluvial fan, and a hummocky moraine covered by rockfall deposits. Our results reveal the geomorphic history of the three deposits and their connectivity through sediment cascade. These results highlight the development of rapid and most probably transient landscape changes in high Alpine regions during the Lateglacial-Holocene transition, with an increase in sediment flux and the establishment of paraglacial and periglacial geomorphic processes.