Modelado gravimétrico de una sección entre el margen continental del sudeste de Brasil y el área emergida adyacente
E.F. La Terra, M. Tupinambá, A.R. Silva and S.L. Fontes
Journal name: Geociencias Aplicadas Latinoamericanas
Issue: Vol 2, No 2, October 2015 pp. 1 - 16
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This study was conducted in a gravimetric section between the continental margin and the onshore area of southeastern Brazil, encompassing the northern portion of the Santos Basin and the Neoproterozoic Brasília and Ribeira mobile belts. Free-Air gravimetric terrestrial and satellite data have been fixed and calculated for Free-Air anomaly and used as the basis for the 2D gravity modeling. Constraints imposed to the 2D gravity model were based on magnetotelluric model 2D inversion for the terrestrial part of the section and model of joint inversion and 2D seismic reflection migrated in time for the Santos Basin. Residual data were calculated from the Free-Air anomaly subtracted from the regional field and were used to associate the shallow part of the model to the geophysical models. In the area of the continental margin, crustal and lithospheric thinning was observed below shallow shelf and in the proximal part of the Santos Basin. Gravity data of the regional field were calculated from a polynomial fit to most Free-Air anomaly data were used to model and fix the lower crust and lithospheric mantle. The fit of the model to regional data was done only it was infered keels at the base of the lithosphere, interpreted as subducted paleoplates situated below suture zones in Brasilia and Ribeira belts. This model fits the observed gravity data with error less than 8% of the total gradient.