The Paleozoic Claromecó Basin (Argentina): 3D lithospheric scale density model

VAZQUEZ LUCERO, S.; BOTT, J.; SCHECK-WENDEROTH, M.; VIZÁN, H.; BALESTRINI, F.; PREZZI, C.; GOMEZ DACAL, M.L.

Hamburgo

Congreso; Latin American Colloquium of Geoscience; 2019

Universität Hamburg

The Paleozoic Claromecó basin is located to the southeast of Buenos Aires Province between 37°- 39° S and 61°- 63° W and has been subject of multiple geological and geophysical studies. Different hypotheses and mechanisms have been proposed for the genesis of this basin, as well as for the deformation of the Australes Ranges.The principal goal of this work is to contribute to a better knowledge of the Claromecó basin evolution on the basis of the development of a lithospheric scale 3D gravity forward model. For the model construction, we integrated several data, such us geological information, a global gravity model (EIGEN 6c4), well data (Lesta and Sylwan, 2005), seismic tomographies, and pre-existing 3D models of the Colorado basin (Autin et al., 2016). We used the software IGMAS+ to develop our model and fit the measured gravity, by modifying the free parameters: the lower and upper crust top layers.Concerning densities, we parameterized the lithologies by assigning constant densities for each unit. For the Colorado basin area, we selected values consistent with Autin et al. (2016) and used the bulk density values published for the Claromecó basin sediments. Our model allows to gain insight into the Moho depth, the variations of the thickness of the sedimentary infill and the upper and lower crust, in the studied area. We also propose a tentative location of the southern limit of the Rio de la Plata craton. Our results contribute to the understanding of the geodynamic evolution of Claromecó basin and of the tectonic processes which affected the southwestern margin of Gondwana during Paleozoic times.