| Summary: | This paper reflects the first results of a crustal study in the South Atlantic Ocean, in the region of the shelf, slope and Argentine continental rise. In the region from 50° to 66° west longitude and 36° to 50° south latitude. A gravity model of upper continental and oceanic crust, where the geometry and boundaries of the Argentina basin is emphasized, is presentedIn order to obtain the gravitational effect of the basins offshore, a sequence of filters applied to the gravimetric anomalies. To do this: A) Bouguer anomalies with topographic correction (ABCT) were calculated. B) The upper crust was normalized by deduct the gravitational effect of the basins to the ABCT, from global models isobaths, obtaining Bouguer anomalies with geological correction (ABCG). C) A regional was obtained by upward extension to the height of 20 km (RegUp20), optimal height separation effects according to the power spectrum of ABCG. D) The gravitational effect of the crust (ResCS) was obtained by the difference between ABCT and RegUp20, this has the effect of residual basins and intrusive bodies in middle and upper crust (SDRs), these bodies are outlined as conspicuous anomalies of 50-100 km wavelength. E) In order to obtain the gravitational effect of the sediments that fill the basin the positive effects of SDRs (seaward-dipping reflectors) were removed, applying an isostatic decompensated correction (DA) under the concept of local compensation. Thus the residual anomaly of continental margin basins (ResCC) or residual anomaly of corrected crust, which allows evaluating in its entirety the boundaries and depth of the basin was obtained. A 3D model, three-layer, calculated by inverting the residual gravimetric ResCC prepared. In this variable density values for sediment and constant for the upper crust, lower and upper mantle are considered. These results allowed us to obtain the boundaries of the Argentina Basin. Revealing gravimetric aspects related to the morphology and constitution of the upper crust in the continental margin. © ...
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