Modelado de densidad, temperatura y reología de la altiplanicie del Macizo Norpatagónico

Abstract

The North Patagonian Massif plateau (NPM) was formed by a sudden uplift - from depths below sea level in the Paleocene to more than 1200 masl in the Oligocene. The mentioned uplift, that differenciated the study area from the surrounding basins by more than 500 m, did not leave evidence of appreciable intemal deformation. The investigation about the physical characteristics of the plateau and their difference with the surroundings can contribute to the knowledge of the causes and the history of the formation of the study zone. With the aim of characterizing the plateau area in terms of density, temperatures and rheology, different 3D lithospheric-scale models have been developed by the integration ofthe available geological and geophysical data. According to the density modeling, an important contrast between two areas of the model exists, that fairly coincides with the Paleozoic terranes of Chilenia and Patagonia. Other results of this model are the greater crustal thickness of the plateau in comparison with its surroundings and the possibility of an isostatic balance of the area. In the temperature model, the shallow zones of the crust inside the NPM plateau are colder than the surroundings, but the opposite is happening at greater depths. The rheological model indicates that the strength is concentrated in the shallow part of the crust. On the contrary, the deeper parts of the crust and the lithospheric mantle are weak.