The evolution of the hinterland and marginal basins of Brazil is related to the tectonic events that originated the South Atlantic Ocean. The transitional post-rift sequence of aptian-albian age is the last preserved stage of the sedimentary record in the evolution of the Brazilian Northeast rift systems. In this context, the Crato Formation of the Araripe Basin characterized by apparent monotonous laminated limestones interbedded with terrigenous deposits, are unique for its exceptional fossiliferous preservation. Punctual sedimentological and paleontological analyses of this unit provided innumerous conflicting data of paleoenvironmental interpretation. The recent discovery of microbial activity in the limestones, interpreted before as originated by purely chemical precipitatation, promotes new research based in this new approach. In addition to its occurrence in the Araripe Basin, the Crato Formation also occurs in the Jatobá and Tucano basins, as discontinuous relicts of the largest extension occupied by its original deposits. Despite some sedimentological data provided, the developed works in the area failed in present more discerning data as isotopic and magnetic susceptibility correlation curves of the different occurrence sites. In that manner, the here proposed multi-proxy analyses is necessary to support paleoenvironmental interpretations, since traditional sedimentary methods were not enough to solve problems concerning origin, stratigraphic positioning and definition of the mechanism of preservation of fossils in this worldwide renown Fossil Konservat Lagerstätte of the Cretaceous. The integration of macro, micro and ultrastructural description of limestones and siliciclastics allied with geochemical, stratigraphical and structural data will be fundamental to regional correlations as well as in the definition of the paleogeographic scenario. The definition of extent and positioning of the first marine ingression in the interior of the Brazilian northeast during Gondwana fragmentation is also intended.
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