A modelagem de sistemas de falhas extensionais, nucleados em zonas de fraqueza preexistentes, e sua aplicação à bacia minas no Quadrilátero Ferrífero, Minas Gerais.

Abstract

Analogue models were used to investigate the development of extensional basins above reactivated basement faults. All the experiments were set up with a fault system configured both oblique and orthogonal to the extension direction. In one sequence of eight sand models, the simple-shear model simulated the lithospheric stretching. The extension was applied on diverse fault dip angles in different extension directions. In a second sequence, the rift systems were simulated by homogeneous pure-shear acting on a brittle crust (sand) and on a brittle-ductile system (a silicone layer above the sand layer). The 3-D analysis of the resulting structures revealed that the geometry of basins controlled by preexistent basement faults depends essentially on two factors: the angle between extension direction and fault-strike, and the involvement of the ductile crust. In map-view, the structures were correlated to the Minas Basin, in the Quadrilatero Ferrifero, and ari ENE extension direction was proposed.