The Camaquã extensional basin: Neoproterozoic to early Cambrian sequences in southernmost Brazil

The Camaqua Basin is an extensional post-orogenic and pre-cratonic rift system of Neoproterozoic-Early Cambrian age located in the Gaucho Shield, Rio Grande do Sul, southernmost Brazil. The basin is divided into a series of small sub-basins which were filled with the Camaqua Group, a thick (>9,000 m) unit composed of three formations: (i) the siliciclastic Marica Formation, (ii) the volcano-sedimentary Crespos Formation and (iii) the siliciclastic Santa Barbara Formation. These units correspond to three major stratigraphic sequences, and are divided into higher order sequences. Provenance and paleocurrent analysis of the siliciclastic deposits show a close relationship of the sourcearea with the lithologies that occur today in the neighborhood of these deposits, suggesting that no important lateral transport took place along the border faults. Paleocurrent measurements indicate a northern position for the marine body that cyclically invaded the basin.