Early Pleistocene complex cut-and-fill sequences in the Alps

Dieleman, Catharina; Christl, Marcus; Vockenhuber, Christof; Gautschi, Philip; Akçar, Naki (2022). Early Pleistocene complex cut-and-fill sequences in the Alps. Swiss journal of geosciences, 115(1) Springer 10.1186/s00015-022-00411-2

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Cut-and-fill sequences are the result of climatically or tectonically induced alternating aggradation and incision phases of a fluvial system. A recently established cosmogenic nuclide chronology of the Cover Gravels (Deckenschotter in German) in the northern Alpine Foreland, which are the oldest Quaternary glaciofluvial gravels and comprise evidence of early Pleistocene glaciations, suggests a cut-and-fill build-up. This suggested cut-and-fill architecture challenges the morphostratigraphy. The Deckenschotter deposits represent a suitable archive for reconstructing drainage patterns, base level changes, and the landscape evolution of the northern Alpine Foreland during the early Pleistocene. In this study, we focused on the highest morphostratigraphic Deckenschotter sites: three at Irchel and one in the area around Lake Constance. Sediment analyses were performed to determine their provenance and depositional environments. The geochronology was established using isochron-burial dating. The results indicate that the sediments were transported from the Central and eastern Central Alps, as well as from the Molasse, to the foreland and deposited in a proximal glaciofluvial environment. Based on these findings, we propose that the Deckenschotter are cut-and-fill sequences that accumulated in three stages during the early Pleistocene at ca. 2.5 Ma, ca. 1.5 Ma, and ca. 1 Ma. The presence of a cut-and-fill system implies that the regional base level was relatively constant during the early Pleistocene. In addition, the ca. 2.5 Ma glaciofluvial gravels document the first evidence of glaciers in the northern Alpine Foreland. This timing is synchronous with the onset of Quaternary glaciation in the northern hemisphere at ca. 2.7 Ma.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Exogenous Geology

UniBE Contributor:

Dieleman, Catharina Jorinna, Akçar, Naki

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1661-8726

Publisher:

Springer

Language:

English

Submitter:

Catharina Jorinna Dieleman

Date Deposited:

17 Jun 2022 07:48

Last Modified:

05 Dec 2022 16:20

Publisher DOI:

10.1186/s00015-022-00411-2

BORIS DOI:

10.48350/170729

URI:

https://boris.unibe.ch/id/eprint/170729

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