Glacial erosion by the Trift glacier (Switzerland): Deciphering the development of riegels, rock basins and gorges

A long-lasting question in glacial geology is how and fast glaciers were able to shape the distinctive landscapes of Alps. This study contributes understanding on formation overdeepened basins, especially processes amount time involved. We examine remarkably high (150 m) cross-valley bedrock riegel associated overdeepening located front Trift glacier central Swiss combined approach field survey with measurements two cosmogenic nuclides, 10Be in-situ 14C, a numerical model was used determine spatial erosion patterns riegel. Ten samples taken along transects; one perpendicular flow direction, from outside Little Ice Age (LIA) extent down centre riegel, other following former ice-flow direction across Analysis measured nuclide concentrations shows that sample LIA constantly exposed since retreat Egesen stadial (~11.5 ka). The inside indicate distinct trend increasing rates 0 mm/a near ice margin all top resulting minimum are 0.5–1.1 (10Be) 0.6–>1.8 (in-situ 14C) which correspond depths 1.6–>3 m 1–>5 (14C). extremely low at highlight substantial (predominantly abrasion) surface during late Holocene coverage. Field observations suggest and, as consequence, due combination valley shape, structures, confluence hydrology. further hypothesise gorge key factor responsible for this impressive overdeepening, by lowering threshold subglacial meltwater, effectively decoupling height depth overdeepening.