Link between concentrations of sediment flux and deep crustal processes beneath the European Alps

Garefalakis, Philippos Erich; Schlunegger, Fritz (2018). Link between concentrations of sediment flux and deep crustal processes beneath the European Alps. Scientific Reports, 8(1) Nature Publishing Group 10.1038/s41598-017-17182-8

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Large sediment fluxes from mountain belts have the potential to cause megafans to prograde into the neighbouring sedimentary basins. These mechanisms have been documented based from numerical modelling and stratigraphic records. However, little attention has been focused on inferring temporal changes in the concentrations of supplied sediment from coarse-grained deposits. Here, we extract changes of this variable in the field from a Late Oligocene, c. 4 km-thick suite of fluvial conglomerates situated in the North Alpine foreland basin, which evolved in response to the tectonic and erosional history of the Alps. We measure a decrease in channel depths from >2 m to <1 m and an increase in the largest grain sizes from <15 cm to >20 cm from the base to the top of the suite. These constraints are used to calculate an increase in fan surface slopes from <0.3° to >1.0° based on the Shields criteria for sediment entrainment. We combine slope and bulk grain size data with the Bagnold equation for sediment transport to infer higher concentrations of the supplied sediment. We use these shifts to propose a change towards faster erosion and a steeper landscape in the Alpine hinterland, driven by mantle-scale processes beneath the Alps.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Garefalakis, Philippos Erich and Schlunegger, Fritz

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

2045-2322

Publisher:

Nature Publishing Group

Language:

English

Submitter:

Fritz Schlunegger

Date Deposited:

17 Jan 2018 13:54

Last Modified:

10 Mar 2021 07:27

Publisher DOI:

10.1038/s41598-017-17182-8

BORIS DOI:

10.7892/boris.108819

URI:

https://boris.unibe.ch/id/eprint/108819

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