The post-basaltic sediments of the Cretaceous Bauru Group in the Paraná Basin cover an area of 117,000 km2 in São Paulo State, and are subdivided into the Caiuá, Pirapozinho, Santo Anastácio, Birigüi, Araçatuba, Adamantina and Marília 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 Caiuá/Pirapozinho formations (first sequence), initially filled the basaltic substratum troughs. After an erosional interval, the Santo Anastácio 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 Marília Formation.
Paula e Silva, F.; Chang, H. K.; Caetano-Chang, M. R. – 2009 – Sedimentation of the Cretaceous Bauru Group in São Paulo, Paraná Basin, Brazil. Journal of South American Earth Sciences. V.28, p. 25-39.