Lithofacies associations and probable depositional environments of the São Roque Group in the region of Votorantim and Salto de Pirapora, São Paulo

Abstract

The present study aims at characterizing the sedimentary facies of Proterozoic rocks of the São Roque Group that outcrop in the region including the cities of Votorantim and Salto de Pirapora and neighbourhood (southeast of the state of São Paulo, Brazil). These rocks were mapped at a scale of 1:50.000; included is a structural-geological analysis that supports the understanding of the spatial distribution of sedimentary facies and the stratigraphic units. Four associations of lithofacies and related depositional environments were recognized. They comprise from base to top: A. lower siliciclastic association, probably associated with deep-water sedimentation, mostly related to a turbiditic succession; B. intermediate siliciclastic association, corresponding to a shallow-water platform with prograding characteristics; C. transitional clastic-carbonate association, here interpreted as a transition from shallow platform deposition to a mixed carbonate tidal flat environment (subtidal to intertidal conditions); and D. upper impure carbonate association that may correspond to a tidal flat governed by tidal currents and related oscillatory movements (intertidal to supratidal conditions). These associations were informally correlated with previously proposed stratigraphic subdivisions of the São Roque Group in the region (namely Estrada dos Romeiros, Voturuna and Pirapora formations).