This work provides a general overview of the tectono-stratigraphic evolution of the Eastern Brazilian Margin, discussing the main phases of subsidence and sedimentation and in particular, the structural styles and depositional megasequences of selected basins. The Mesozoic sedimentation along the Brazilian continental margin started with the breakup of Western Gondwana in the Late Jurassic/Early Cretaceous. The rifting of the southernmost part of South America Plate was heralded by the extrusion of flood basalts in the Paraná, Campos and Santos basins. The syn-rift phase is associated with synthetic and antithetic faults forming several half-grabens filled with fluvial-deltaic sediments of the Continental Megasequence. The Transitional Megasequence is characterized by evaporite deposition from the Santos towards the Sergipe/Alagoas Basin, and salt movements constitute one of the most important controls on stratigraphic and structural features, being responsible for several exploratory plays in deep water regions. The drift Marine Megasequence, presently bearing most of the hydrocarbon production and reserves, may be subdivided into a carbonate Restricted Marine Supersequence (Albian to Turonian) and a siliciclastic Open Marine Supersequence (Late Cretaceous to Quaternary). The interpretation of deep water depositional systems and the rift architecture at the transition from continental to oceanic crust constitute the major challenges for petroleum exploration in the next century.

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lhe sedímentary sequenee from AI1;Jian toSantonian in Sergipe-Alagoas Basin comprises Riachuelo and Cotinguiba fonnations .. It representa the initial development of ao open marine sedimentation in the tectonic-sedimentary evolution of the Braziliancontinental margin basins. lhe Albian/Cenomaniao rocks (Ríachuelo Formation) are eomposed of coarse terrigenous sediments (Angieo Member) at the border of the basin, grading lateral1y to shales interbedded with earbonates (Taquari Member), and are topped by ao essentially carbonatic sequenee with development of large oolitíc bars and algalie biolithites (Maruim Member), deposited in shallow matine conditions. lhe Turonian to Santonian rocks (Cotinguiba Formatíon) are composed mostly of laminated hemipelagic ealeilutites, deposited at the slope of a earbonate platfonn whích was entirely eroded. Shales from the lower part of Taquari Member have good oil-source potential but are thermally ímmature. The best prospeets of the studied sedimentary sequenee are fraetured calcilutites, associated with halokynetic struotures and paleo-highsbasements.

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