Geowissenschaftliches Seminar

am Fachbereich Umwelt & Biodiversität (Abteilung Geologie)

 

 ‘Geodynamics and glaciofluvial processes in Northern Switzerland around the Early and Middle Pleistocene’

Thomas Pollhammer

(Ergebnisse seiner Doktorarbeit)

Zusammenfassung:

Glaciofluvial outwash forms under short lived boundary conditions (between glacier terminus and a base-level/receiving water). With the onset of glacier meltdown aggradational river surfaces become abandoned quickly, preserving information on depositional conditions and postdepositional tectonic influences in their elevation and geometry. In foreland regions, preservation potential is high and with uplift, extensive terrace staircases may form. In Northern Switzerland, glaciofluvial terraces of up to Early Pleistocene age are preserved. It is assumed, that they are the product of more than ten glacial periods, however, the associated paleo-river networks are hard to reconstruct, since the older terraces are often preserved very patchily, and frequently are topographically unconfined. Also a major drainage reorganization assumed in Early Pleistocene further complexes the situation. On the way of deciphering the paleogeography, sedimentologic analysis and in recent years also absolute age dating of the oldest gravel bodies revealed a complex structure, of terraces sequences and normal stratigraphic positions. A detailed morphologic analysis is needed, to reveal possible paleo-river pathways.

A GIS based toolset has been presented (Pollhammer et al. 2021) that allows for reconstructing paleo-river long profiles from digital elevation models and other data. This toolset has been adapted and applied in the Swiss Alpine Foreland utilizing existing sedimentological and age data in the morphologic context and delineate possible flow paths.

Wann: Dienstag, 30. Jan., 2024, 15 Uhr

Wo: HS 431

Twitter   Facebook  Instagram