Sedimentation of the Cretaceous Bauru Group in Sمo Paulo, Paranل Basin, Brazil

The post-basaltic sediments of the Cretaceous Bauru Group in the Paranل Basin cover an area of 117,000 km2 in Sمo Paulo State, and are subdivided into the Caiuل, Pirapozinho, Santo Anastلcio, Birigüi, Araçatuba, Adamantina and Marيlia formations. The sedimentation of Bauru Group was controlled by a combination of post-basaltic tectonism (responsible for the migration of the depocenters), erosion and climatic changes. Three main depositional phases are separated by two erosive/non-depositional phases defining depositional sequences. The fluvial-lacustrine deposition represented by the Caiuل/Pirapozinho formations (first sequence), initially filled the basaltic substratum troughs. After an erosional interval, the Santo Anastلcio Formation was deposited and overlapped (eastward) underlying beds (second sequence). Renewed erosion and tectonism initiated the last depositional sequence, with the migration of the depocenter to the Queiroz depression. High topographic gradients initially favored the accumulation of fluvial deposits of braided systems of the Birigüi Formation. With the enlarging of the depositional area, a lacustrine system was formed (Araçatuba Formation) and overlapped by a fluvial system with progradation of lacustrine deltas (Adamantina Formation). The sedimentation of the Bauru Group ceased with deposition of marginal fans of Marيlia Formation.