ESTRUTURAS INDUZIDAS POR ABALOS SÍSMICOS NA FORMAÇÃO SANTA BÁRBARA (NEOPROTEROZÓICO III - EOCAMBRIANO), BACIA DO CAMAQUÃ, RS: O EXEMPLO DO PASSO DA CAPELA

Abstract

This paper describes seismically-induced features discovered in sandstones of the Neoproterozoic-Cambrian Santa Barbara Formation (Camaqua Group, Rio Grande do Sul, Brazil). These features include faults with normal components and soft-sediment liquefaction structures, both related to synsedimentary seismic activity. Structural analysis of faults of four different generations has shown the same WNW-ESE direction of extension, orthogonal to the strike of the basin. This direction in association with regional provenance and paleocurrent data has allowed one to infer an extensional tectonic regime during the development of the upper formation of the Camaqua Basin, particularly at its eastern occurrences.