A deglaciation model of the Oberhasli, Switzerland

Abstract

We combine 10Be surface exposure ages from boulders and bedrock, field observations and measurement of bedrock ice‐flow direction indicators with numerical ice surface models to develop a model of the evolution of the Oberhasli area in the central Swiss Alps from the Last Glacial Maximum (LGM) to the early Holocene. Surface exposure ages from bedrock and boulder samples imply that the highest ice surface at the glacial trimline in Haslital was attained at 23.0 ± 0.8 ka. Significant retreat followed no later than 17.7 ± 0.8 ka. Several boulders were let down on the Gelmerhörner ridge during lowering of the ice surface of the Aare LGM glacier. Their exposure ages of 16–14 ka suggest that patches of remnant ice persisted on the trough shoulder until the Bølling–Allerød interstadial. Lateglacial glacier systems in the High Alps were of a dendritic character, confined to the trunk valleys and cirques. Based on combined evidence from glacial erosional marks, surface exposure ages and numerical modelling we have been able to constrain the likely terminal position and ice surface of the Egesen stadial glacier (Younger Dryas equivalent) in Haslital. Exposure ages from the trough floor imply that deglaciation was completed at the end of the Younger Dryas at 12.2–10.8 ka.

Double response of glaciers in the Upper Peio Valley (Rhaetian Alps, Italy) to the Younger Dryas climatic deterioration

“…of the two studied glaciers during the different recognized phases were stored in attribute tables associated with shape files. (2008) and Wirsig et al (2016), following Kohl & Nishiizumi (1992) and Ivy-Ochs (1996). Past contour lines were drawn every 50 m for each reconstructed phase and were joined, for the deglaciated area, to original vectorial contours of Carta Tecnica Provinciale di Trento (Sheets Nr.…”

Deglaciation history at the Alpine‐Mediterranean transition (Argentera‐Mercantour, SW Alps) from 10Be dating of moraines and glacially polished bedrock

“…Cossart et al, 2010;Coutterand, 2010;Wirsig et al, 2016). Cossart et al, 2010;Coutterand, 2010;Wirsig et al, 2016).…”

“…The LGM probably culminated around 21 ka in both the north and the south parts of the Alps (e.g. These two re-advances may be attributed to the two most significant climatic deteriorations of Termination 1, the Heinrich event 1 at ∼16.8 ka and the Younger Dryas at 12.9-11.5 ka (Bond et al, 1992;Böhlert et al, 2011;Clark et al, 2012;Wirsig et al, 2016). The LGM stage is followed by at least two cold periods well expressed in the northern and eastern Alps: the Gschnitz re-advance is dated at 17-16 ka (Maisch, 1992;Ivy-Ochs et al, 2006a, 2006b and the Egesen stadial at 13.0-11.5 ka (Ivy-Ochs et al, 2009;Schindelwig et al, 2012).…”

Methods and uncertainty estimations of 3-D structural modelling in crystalline rocks: a case study

“…Glaciation and glacial retreat contributed to the latest history of the area (Wirsig et al, 2016). Basal erosion and the latest young (17.7 ka, Wirsig et al, 2016) retreat ages produced excellent outcrop conditions, as most outcrops are glacially polished and above the treeline, exposing bare bedrock.…”

“…Basal erosion and the latest young (17.7 ka, Wirsig et al, 2016) retreat ages produced excellent outcrop conditions, as most outcrops are glacially polished and above the treeline, exposing bare bedrock.…”