BORIS Theses

BORIS Theses
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Paleo-glacier history and geomorphic evolution in the Western European Alps since the Last Glacial Maximum

Serra, Elena (2021). Paleo-glacier history and geomorphic evolution in the Western European Alps since the Last Glacial Maximum. (Thesis). Universität Bern, Bern

21serra_e.pdf - Thesis
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Alpine regions are active environments constantly transformed by the interplay of a variety of glacial, periglacial and postglacial geomorphic processes, operating over different time scales and largely regulated by Quaternary climatic oscillations between glacial and interglacial conditions. In the European Alps, significant research efforts have focused especially on the glacial and postglacial history since the Last Glacial Maximum (LGM; 26-19 ka). However, due to the low preservation of glacial landforms and deposits along Alpine valleys, most paleoglacial and postglacial investigations have focused on isolated climatic periods and/or confined Alpine sectors. The present PhD thesis provides new quantitative data tracing post-LGM paleo-glacier and landscape evolution in the western Swiss and Italian Alps (Dora Baltea catchment and Sanetsch high-elevation Pass). I adopted a multi-method approach combining (1) geomorphological mapping, (2) state of the art geochronology techniques, and (3) GIS and numerical ice-flow modelling reconstruction of 2D-3D paleo-ice configurations. My PhD results indicate that the main Dora Baltea glacier and its tributaries fluctuated in response to Lateglacial (19.0-11.7 ka) climatic variations, with significant ice retreat from the foreland to the High Alps interrupted by multiple stages of stillstand or re-advance during periods of climatic deterioration. For the last Lateglacial cold events (Oldest and Younger Dryas), I propose similar-to-today precipitation pattern over the Dora Baltea catchment associated to 3-4°C temperature decrease compared to present-day. In addition, my results reveal significant hillslope and sediment transfer activity closely following Lateglacial local ice retreat, suggesting a major role of paraglacial slope relaxation and glacial/periglacial sediment remobilization in triggering the postglacial geomorphic response. Finally, millennial-scale erosion dynamics appear influenced by the glacial overprint on Alpine landscapes, with steep slopes and high reliefs modulated by bedrock erosional resistance, promoting intense glacial, postglacial and periglacial erosion processes with well-persisting effects during interglacial periods.

Item Type: Thesis
Dissertation Type: Cumulative
Date of Defense: 3 December 2021
Subjects: 500 Science > 550 Earth sciences & geology
Institute / Center: 10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geological Sciences
Depositing User: Hammer Igor
Date Deposited: 03 Feb 2022 16:16
Last Modified: 03 Feb 2022 16:18

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