Estratigrafia de sequências e cronoestratigrafia sísmica da porção central da Bacia de Pelotas, Brasil

Abstract

From the Neocomian, rift-type basins originated during the process of continental opening that fragmented the Gondwana Supercontinent. In this context, the Pelotas Basin was developed in the southern end of the Brazilian Continental Margin, being precursor of the other basins located to the northeast. A part of the continental crust and part of the oceanic crust was filled by sedimentary and volcanic rocks from the Mesozoic to the Late, receiving a thick sequence of sediments which mainly includes shales and sandstones and, Conglomerates and extrusive basaltic rocks. Sequence Stratigraphy, the scope of this work, is the branch of stratigraphy that is dedicated to understanding the stratigraphic framework of sedimentary basins by analyzing the sedimentary response to changes in the baseline level and the depositional tendencies that emerge from the relationship between The space of accommodation and the sedimentary contribution. For this, the Opendtect Pro® software (academic license version) was used to allow the processing, analysis and visualization of a sedimentary basin in a knowable workflow. The seismic data from a line located in the central portion of the Pelotas Basin provided the basis for the interpretation and hierarchy of the sequences for this basin. The horizons previously described and biostratigraphically calibrated available in the literature for this basin were used as the basis for the seismic interpretation. From the analysis of the section it was possible to recognize and hierarchize the sequences of the Pelotas Basin at a higher level of detail, not yet observed for this basin, and from these results a chart was built within the chronostratigraphic framework for the Pelotas Basin.