Аннотация:With the end of the Eocretaceous volcanic manifestations (133 Ma), the southeastern portion of the South American Plate underwent tectonic restructuring, which generated basins that encompassed continental sedimentary sequences.The tectonic events responsible for the accumulation of such sequences can be divided in two main phases.The first phase is related to the Eocretaceous thermal subsidence, resulting in the formation of the Caiuá basin.The second phase, during which the Bauru Basin was originated, was related to the Neocretaceous uplifts in southwestern Minas Gerais and southern Goiás, related to the magmatic activities.The analyses showed that the Caiuá Basin is characterized by a depression whose depocenter was located to the south.At that time, the climate was arid, as attested by the aeolian sedimentation.The Bauru Basin, generated in the Neocretaceous and with depocenter located to the northern, encompasses playa-lake and alluvial deposits of arid to semi-arid climate, with sedimentological and paleopedological characteristics suggestive of more humid climatic conditions.By means of stratigraphic analysis based on wells and outcrops and aided by petrographic studies, two surfaces were identified that record important changes in the Bauru Basin tectonic and paleoenvironmental conditions.The first, related to the origin of the Bauru Basin, marks the tectonic restructuring that affected the southeastern portion of the South American Plate.It separates the Eocretaceous desertic system tract from the Neocretaceous lacustrine/playalake/alluvial system tract.The second surface at the top of the lacustrine/playa-lake sequence records changes in the tectono-sedimentary, as well as paleoenvironmental and paleoclimatic conditions.
