Three-dimensional gravity modelling of a Quaternary overdeepening fill in the Bern area of Switzerland discloses two stages of glacial carving

Bandou, D.; Schlunegger, F.; Kissling, E.; Marti, U.; Schwenk, M.; Schläfli, P.; Douillet, G.; Mair, D. (2022). Three-dimensional gravity modelling of a Quaternary overdeepening fill in the Bern area of Switzerland discloses two stages of glacial carving. Scientific reports, 12(1), p. 1441. Springer Nature 10.1038/s41598-022-04830-x

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The geometry of glacial overdeepenings on the Swiss Plateau close to Bern was inferred through a combination of gravity data with a 3D gravity modelling software. The target overdeepenings have depths between 155 and > 270 m and widths between 860 and 2400 m. The models show incisions characterized by U‐shaped cross‐sectional geometries and steep to over‐steepened lateral anks. Existing stratigraphic data reveals that the overdeepenings were formed and then lled during at least two glacial stages, which occurred during the Last Glacial Maximum (LGM) within the Marine Isotope Stage (MIS) 2, and possibly MIS 6 or before. The U‐shaped cross‐sectional geometries point towards glacial erosion as the main driver for the shaping of the overdeepenings. The combination
of the geometries with stratigraphic data suggests that the MIS 6 (or older) glaciers deeply carved the bedrock, whereas the LGM ice sheet only widened the existing valleys but did not further deepen them. We relate this pattern to the di erent ice thicknesses, where a thicker MIS 6 ice was likely more powerful for wearing down the bedrock than a thinner LGM glacier. Gravity data in combination with forward modelling thus o ers robust information on the development of a landscape formed through glaciers.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Palaeoecology

UniBE Contributor:

Bandou, Dimitri Tibo; Schlunegger, Fritz; Schwenk, Michael Alfred; Schläfli, Patrick Fabian; Douillet, Guilhem Amin and Mair, David

Subjects:

500 Science > 550 Earth sciences & geology
500 Science > 580 Plants (Botany)

ISSN:

2045-2322

Publisher:

Springer Nature

Language:

English

Submitter:

Fritz Schlunegger

Date Deposited:

04 Feb 2022 11:55

Last Modified:

08 Feb 2022 08:15

Publisher DOI:

10.1038/s41598-022-04830-x

PubMed ID:

35087080

Uncontrolled Keywords:

Geology; Geomorphology; Geophysics; Sedimentology

BORIS DOI:

10.48350/164963

URI:

https://boris.unibe.ch/id/eprint/164963

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