Inversão linear de anomalias gravimétricas: distribuição 2-D de densidade na Bacia Sedimentar do Pantanal (MT) a partir de dados gravimétricos

Abstract

ABSTRACT. The main objective of this work is to characterize the density variation within the Precambrian basement rocks of the Pantanal Matogrossense Wetland Sedimentary Basin, under the Rio Taquari alluvial fan. The area, in the alluvial fan of the Taquari River, is limited within parallels 17 • 45'S and 19 • S and by the meridians 56 • 45'W e 55 • 15'W. The gravity modeling of the Bouguer anomaly profiles identified the geometry and the densities of the basement. This method was particularly aimed at verifying structural factors which might have influenced the opening and dynamics of water channels, in the middle Taquari River. These branching channels are observed mainly along a small portion of the Taquari River central floodplain. Direct and inverse models had shown an important depression and internal density variations of the basement of about 0.9 g/cm 3 . The existence of a depression in the neighborhood of a fault suggests thrust between the blocks that form the basement. The extension of the faults across the sedimentary sequence of the Pantanal Formation is evidenced in an apparent resistivity profile, reinforcing the hypothesis of neotectonic activity in Pantanal Basin. 184