Neotectonic reactivations in the Rio Paraíba do Sul Shear Zone (Southeastern Brazil)

Abstract

This study aims to investigate neotectonic activities in the region of the Rio Paraiba do Sul Shear Zone, an important geotectonic feature adjacent to the central segment of the Continental Rift of Southeastern Brazil, and contiguous areas. The methodology used in this work is based on the integration of morphostratigraphic and structural data analysis. The analysis of the fault/striae pairs observed in Cenozoic sediments and weathered basement rocks was highlighted in order to characterize neotectonic stress fields. The relationship among the different fracturing patterns, geologic units affected by these events and overlapping patterns of striae on a same fault plain lead to the characterization of three neotectonic stages which could be correlated to the neotectonic events described for the Southeastern Brazil: E-W left-lateral transcurrent stage (Miocene); E-W right-lateral transcurrent stage (Pleistocene/Holocene); and NW-SE extensional stage (Holocene). These neotectonic stages have a strong relationship with the reactivation of the preexisting structural anisotropies.