Glacial geomorphology of the tableland east of the Andes between the Coyle and Gallegos river valleys, Patagonia, Argentina

We report the results of geomorphological mapping of the high tablelands of Patagonia east of the Andes and between the Coyle and Gallegos river valleys. The map covers a low-relief area of about 3400 km2 at a scale of 1:85,000. It contributes to knowledge of a landscape shaped by lobes of the Patagonian ice sheet and can be used as a tool for further Quaternary studies. The map was built from remote-sensing data, compiled, and analyzed in geographical information system packages and supported by fieldwork. It features glacial landforms including moraine ridges and belts, ground moraine, outwash plains, outwash fans, meltwater channels, traces of glacial lakes, and erratic boulders. Fluvial, aeolian, and volcanic landforms and structural features were also mapped to provide a complete understanding of the landscape. We define three glacial units that record the frontal positions of former piedmont glaciers. The criteria used to define these units are the morphology, maximum relief, boulder content of moraine ridges, and crosscutting relations.Fil: Ercolano, Bettina. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Coronato, Andrea Maria Josefa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; ArgentinaFil: Tiberi, Pedro Eugenio. Universidad Nacional de la Patagonia; ArgentinaFil: Corbella, Jorge Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Marderwald, Guillermina Nuri. Universidad Nacional de la Patagonia Austral; Argentin

Glacial, fluvial and volcanic landscape evolution in the Laguna Potrok Aike maar area, Southern Patagonia, Argentina

We describe the Pleistocene evolution of the landscape in the Laguna Potrok Aike area in southern Patagonia, Argentina, based on a geomorphological survey. Basaltic eruptions generated tablelands and scoria cones between the Late Miocene and Middle Pleistocene, and phreatomagmatic eruptions produced maars during Middle and Late Pleistocene time. The first glaciations during the Early Pleistocene generated a gently undulating to flat landscape that was affected by cryogenic processes; they are documented but not dated. Outwash surfaces indicate that the Greatest Patagonian Glaciation was multi-phased. The eruption that produced Potrok Aike maar truncated terrace levels dating to a Middle Pleistocene glaciation. The abundance of maars dating to this time may be linked to large amounts of water associated with meltwater streams and permafrost. The landscape in the Potrok Aike area has changed little since the Middle Pleistocene and only minor modifications of landforms have occurred due to cryogenesis, moderate fluvial incision, mass wasting and eolian activity.Fil: Coronato, Andrea Maria Josefa. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina. Universidad Nacional de la Patagonia; ArgentinaFil: Ercolano, Bettina. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; ArgentinaFil: Corbella, Jorge Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Tiberi, Pedro Eugenio. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentin