Recostruction of the evolutive stages of Llancanelo Lake and surroundings (southern Mendoza province, western Argentina)

E. ROVERE; R. VIOLANTE; A. OSELLA; M. DE LA VEGA; E. LOPEZ

Mar del Plata

Congreso; GeoSur, International Geological Congress on the Southern Hemisphere; 2010

OGS

Llancanelo Lake is located at the foot of the Andes cordillera in a transitional region between northwestern Patagonia and western dry Pampas. It occupies a tectonic depression surrounded by extensive volcanic fields largely composed of volcanic cones and basaltic flows. As a result it behaved as the main regional depocenter through its evolutionary history, which has been affected by drivers intra and extra basinal sedimentation through different sedimentary processes. Consequently, thick sedimentary and volcaniclasticsequences were deposited in the basin, controlled by tectonic and volcanic factors under fluctuating climatic changes. As the last stage of evolution were dominated by arid conditions, the lake progressively changed from an ancient, largely extended water body, to a presently smaller, endorreic, shallow and highly saline lacustrine environment. Therefore, in the lake and its basin the records of the regional evolution are preserved, what makes the area key region for paleoenvironmental, paleoclimatic and paleovolcanic reconstructions. Geophysical and geological surveys have been performed in order to: 1) define the depocenter geometry and its substratum; 2) evaluate the extension and characteristics of the sedimentary sequence; 3) recognize the volcanic events that occurred during its evolution; 4) reconstruct the evolutionary history of the lake. This contribution synthesizes the present knowledge on aspects related to the conditioning factors that influenced the evolution of the region.