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Miocene to Pleistocene sediment transfer in the Alps-Rhine graben sedimentary system

The Alps-Rhine graben system connects the Swiss Molasse basin with the French-German Rhine rift basin. Several tectonic, climatic, and anthropogenic changes have impacted its development from the Oligocene to today. Sediment transfer is complex due to river segmentation, sediment recycling, and changing source areas in response to drainage reorganizations. This contribution provides new insights into the system dynamics by analyzing the provenance of paleo-Rhine deposits using garnet geochemistry. We present new results from ~70 modern, Pleistocene, Pliocene, and Miocene deposits. Our results show that (1) the rift shoulders supplied the bulk of sediment to the Rhine graben in Miocene and Pliocene times, (2) rift shoulder sources can be discriminated, and sources changed several times in the Pliocene, implying significant system dynamics, (3) a reorganization at the Plio/Pleistocene boundary was caused by the inclusion of the Alps into the drainage, (4) the major sediment source in the Pleistocene Rhine graben is the recycling of Molasse deposits, (5) Alpine sediment was transferred for over 500 km into the Lower Rhine graben during the earliest Pleistocene without significant signal modification, and (6) the Pleistocene deposits in the Upper Rhine show a stable composition, possibly due to reworking, and do not reflect the significant Pleistocene climate dynamics. We conclude that provenance analysis in complex systems is key to understanding system dynamics and drainage reorganizations, however, it is not necessarily able to resolve glacial-interglacial climatic changes at a basin scale.

Details

Author
Jonas Kraus1, Laura Stutenbecker2, Matthias Hinderer1, Christian Hoselmann3
Institutionen
1Technical University of Darmstadt; 2University of Münster; 3Hessian Agency for Nature Conservation, Environment and Geology
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/4fak-m341