TY - JOUR
T1 - Comprehensive temporal and spatial analysis of Early Pleistocene drainage patterns on the Swiss Alpine foreland
AU - Broś, Ewelina
AU - Ivy-Ochs, Susan
AU - Pollhammer, Thomas
AU - Kober, Florian
AU - Grischott, Reto
AU - Salcher, Bernhard
AU - Nørgaard, Jesper
AU - Knudsen, Mads F.
AU - Vockenhuber, Christof
AU - Christl, Marcus
AU - Gautschi, Philip
AU - Maden, Colin
AU - Ylä-Mella, Lotta
AU - Jansen, John D.
AU - Landgraf, Angela
AU - Synal, Hans Arno
N1 - Publisher Copyright:
© 2025 John Wiley & Sons Ltd.
PY - 2025/2
Y1 - 2025/2
N2 - Deckenschotter are glaciofluvial gravels that cap isolated bedrock plateaus and are largely disconnected from today's local drainage. They were deposited when glaciers from the Alps were first extensive enough to reach the northern Swiss foreland, thus providing a unique record of the foreland landscape and its evolution during the earliest Quaternary glaciations. To decipher this record, we employ two robust methodologies: cosmogenic 26Al/10Be burial dating and GIS-based topographic analysis. 26Al/10Be burial ages from both new and published sites are calculated using a consistent procedure with the P-PINI code. Detailed swath projected and local 360° profiles were generated with GIS data in an R-toolset developed specifically for this study. Integrating results from both methodologies with outcrop sedimentological data, we interpret three main periods of Deckenschotter deposition: 1.3–1.2, 1.1–1.0 and ~0.8 Ma. The interpreted age ranges indicate glaciers must have reached the forelands in response to intensifying climatic cooling across the Mid-Pleistocene Transition (1.25–0.75 Ma). Deckenschotter outcrops provide a disjointed image of past topography from which we piece together glacial meltwater pathways in each time interval. Between the glacial phases, stepwise incision of 50–100 m occurred as depicted in the projection profiles, with some spatial variability in magnitude of incision. Incision was driven by decreasing sediment supply during glacial terminations, set against a backdrop of minor foreland uplift. While the path of the Aare River has changed little since the Early Pleistocene, the Rhine River has radically altered its path. Initially a tributary of the Danube River with northward flow, glacial modification to topography led to its re-routing to the west into the lower base-level Aare River-Upper Rhine Graben system. Based on our analysis, we estimate this event occurred after ~0.8 Ma.
AB - Deckenschotter are glaciofluvial gravels that cap isolated bedrock plateaus and are largely disconnected from today's local drainage. They were deposited when glaciers from the Alps were first extensive enough to reach the northern Swiss foreland, thus providing a unique record of the foreland landscape and its evolution during the earliest Quaternary glaciations. To decipher this record, we employ two robust methodologies: cosmogenic 26Al/10Be burial dating and GIS-based topographic analysis. 26Al/10Be burial ages from both new and published sites are calculated using a consistent procedure with the P-PINI code. Detailed swath projected and local 360° profiles were generated with GIS data in an R-toolset developed specifically for this study. Integrating results from both methodologies with outcrop sedimentological data, we interpret three main periods of Deckenschotter deposition: 1.3–1.2, 1.1–1.0 and ~0.8 Ma. The interpreted age ranges indicate glaciers must have reached the forelands in response to intensifying climatic cooling across the Mid-Pleistocene Transition (1.25–0.75 Ma). Deckenschotter outcrops provide a disjointed image of past topography from which we piece together glacial meltwater pathways in each time interval. Between the glacial phases, stepwise incision of 50–100 m occurred as depicted in the projection profiles, with some spatial variability in magnitude of incision. Incision was driven by decreasing sediment supply during glacial terminations, set against a backdrop of minor foreland uplift. While the path of the Aare River has changed little since the Early Pleistocene, the Rhine River has radically altered its path. Initially a tributary of the Danube River with northward flow, glacial modification to topography led to its re-routing to the west into the lower base-level Aare River-Upper Rhine Graben system. Based on our analysis, we estimate this event occurred after ~0.8 Ma.
KW - cosmogenic Be and Al
KW - Early Pleistocene Alpine glaciations
KW - GIS reconstruction
KW - P-PINI burial dating
KW - Swiss Deckenschotter
UR - http://www.scopus.com/inward/record.url?scp=85218199108&partnerID=8YFLogxK
U2 - 10.1002/esp.70000
DO - 10.1002/esp.70000
M3 - Journal article
AN - SCOPUS:85218199108
SN - 0197-9337
VL - 50
JO - Earth Surface Processes and Landforms
JF - Earth Surface Processes and Landforms
IS - 2
M1 - e70000
ER -