A Flexural Model for the Brazilian Thrust Belts

A model of lithosphere behavior under a compressional tectonic regime is proposed for Brazilian thrust belts. The thrust belts used in this paper are restricted to the central part of Brazilian Shield. The proposed model assumes that several faults cut the crust. The topography is created by simple slip to regain isostatic equilibrium in a regional manner by using the flexural model for a thin elastic plate. The predicted gravity signal is compared to the observed along six profiles crossing the study area. The lithosphere elastic thickness is between 40 and 50 km. The Araguaia belt is modeled by a thrust fault toward the Amazon craton, with a dip of 200. Uruacu and Brasilia belts are modeled with two thrust faults each towards the Sao Francisco craton. The Espinhaco belt is poorly modeled because of lack of gravity data.