Possible neotectonic control over the Southern Coast Cliffs of the Bahia State

Abstract

The Cenozoic deposits of the onshore portion of the Espírito Santo and Mucuri basins show strong ruptil structural deformation, being recognized N-S and NE-SW faults, with normal throw and NW-SE and E-W transcurrent faults. The N-S and NE-SW directions are parallel to the structural orientation of the precursor rift of the Brazilian East margin basins, while the NW-SE and E-W directions coincide with the transform faults and zones of oceanic weaknesses that accommodate the lithospheric plates motion. The structural data collected in outcrops along the northern of the Espírito Santo state and in the coastal region of the southern of the Bahia state show that the geomorphological configuration of the cliffs present in southern Bahia was controlled by reactivated rift phase faults, as well as still active transcurrent structures which are responsible to model the current observed relief. The neotectonic activity of such structures was inferred through the recognition of ruptil structures affecting recent sediments. From these data new structural interpretations are proposed for the onshore portion of the Espírito Santo and Mucuri basins and the effects of such tectonic deformation on the lithostratigraphic arrangement of the studied deposits are evaluated.