Geomorphic expression of the southern Central Andes forebulge (37°S,Argentina) |
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| Authors: | Bertrand Nivière Grégoire Messager Sébastien Carretier Pierre Lacan |
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| Institution: | 1. LFCR ‐ UMR 5150/CNRS/Total/University of Pau, IPRA, , F‐64013 Pau Cedex, France;2. Group of Dynamics of the Lithosphere Group, Institute of Earth Sciences “Jaume Almera”, CSIC, , 08028 Barcelona, Spain;3. GET ‐ UMR 5563/CNRS/UPS/IRD/CNES, University of Toulouse, , F‐31400 Toulouse, France |
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| Abstract: | We present a geomorphologic analysis of an east‐west transect located east of the southern Andes of Argentina (~37°S). We observe a succession of zones that underwent erosion and deposition during the Pleistocene. If the proximal Andean foothills are incised, a proximal depozone receives sediments feeding the megafan of the Rio Colorado on the Chadileuvú plain. More distally, the abandoned palaeo‐valleys and bending of the valley floors reflect a localized uplift. Further to the east, another depozone corresponds to the Pampa Deprimida lowland. This pattern is consistent with the presence of a classical flexural geometry of the lithosphere. The distal uplift of the foreland corresponds in terms of location, length (150 km) and amplitude (240 m) to the Andean forebulge modelled by a geophysical approach. In this study, we identify the morphological imprint of this bulge and show its effect on the fluvial activity. |
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