Chemostratigraphic correlation of Devonian-Carboniferous sedimentary sequences at Roboré SUB-BASIN, Bolivia

Abstract

A chemostratigraphic analysis was performed on cutting samples from Devonian-Carboniferous intervals belonging to three wells located in the Roboré sub-Basin, east of Chaco Plain, southeast Bolivia.Using multivariate statistical analysis (Factor Analysis), we have established two main geochemical associations serving as control for the chemistry of the analyzed samples: detrital (clay and heavy minerals) and redox-organic matter association.In addition, different geochemical zones (chemozones or chemofacies) were established by the application of a hierarchical statistical analysis (constrained cluster analysis), both for the detrital and redox-organic matter associations. Furthermore, total correspondence of the established chemozones was observed and better definition of the predefined stratigraphic contacts was obtained after a chemostratigraphic correlation scheme was applied. Taking together our chemostratigraphic data, we have identified an interval that represents a possible marker of Lower Carboniferous glacial event in the Roboré sub-Basin. We have evaluated the general characteristics of the sources of sediment provenance along the studied sequences. In conclusion, we proposed a large active continental margin accretionary complex tectonic setting for Los Monos (Late Devonian) and Tupambi (Mississippian) formations in the Roboré sub-Basin (Chaco Plain).