Assessment of geomorphological and hydrological changes produced by Pleistocene glaciations in a Patagonian basin

SCORDO, FACUNDO; SEITZ, CARINA; MELO, WALTER D.; PICCOLO, M.CINTIA; PERILLO, GERARDO M.E.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2018 vol. 83 p. 195 - 209

0895-9811

This work aims to assess how Pleistocene glaciations modeled the landscape in the upper Senguer Riverbasin and its relationship to current watershed features (drainage surface and fluvial hydrologicalregime). During the Pleistocene six glacial lobes developed in the upper basin of the Senguer Riverlocalized east of the Andean range in southern Argentinean Patagonia between 43 36? - 46 270 S. Todescribe the topography and hydrology, map the geomorphology, and propose an evolution of the studyarea during the Pleistocene we employed multitemporal Landsat images, national geological sheets and amosaic of the digital elevation model (Shuttle Radar Topography Mission) along with fieldwork. Themain conclusion is that until the Middle Pleistocene, the drainage divide of the Senguer River basin waslocated to the west of its current limits and its rivers drained the meltwater of the glaciers duringinterglacial periods. However, processes of drainage inversion and drainage surface reduction occurred inthe headwater of most rivers of the basin during the Late Pleistocene. Those processes were favored by arelative shorter glacial extension during LGM and the dam effect produced by the moraines of the PostGPG I and III glaciations. Thus, since the Late Pleistocene, the headwaters of several rivers in the basinhave been reduced, and the moraines corresponding to the Middle Pleistocene glaciations currentlydivide t