Basement-Involved and Detached Phases of Deformation in the Evolution of Fold-Thrust Belts: Examples from the Southern Cordilheira do Espinhaço and the Paramirim Deformation Corridor, Brazil

Abstract

The southern Cordilheira do Espinhaço in southeastern Brazil, is a Late Proterozoic (Brasiliano/Pan-African) fold-thrust belt that developed along the eastern margin of the N-S trending portion of the São Francisco craton. This N-S-trending and west-verging belt involves both a basement complex, composed of > 1.8 Ga crystalline rocks, and Middle to Late Proterozoic metasedimentary units. The Espinhaço fold-thrust belt displays an antiaxial curve in map view, such that the central portion of the belt has propagated further west into the foreland than the northern and southern ends. At its north end, the Espinhaço fold-thrust belt connects to the Paramirim corridor, a deformation belt which trends NNW-SSE and defines the boundary between the E-W trending segment of the Sao Francisco craton and the N-S trending segment of the craton. The Paramirim corridor, which is doubly vergent, also involves a basement complex and Middle to Late Proterozoic strata. It is composed of two oblique-slip to frontal embryonic fold-thrust belts, which root in a central strike-slip system. The Espinhaço fold-thrust belt and the Paramirim corridor represent inverted segments of a Middle to Late Proterozoic-age passive margin and failed rift, respectively.