Arquitetura deposicional e evolução da seqüência aluvial neocretácea da porção setentrional da Bacia Bauru, no sudeste brasileiro

The macroforms reconstructions using facies and architectural element analysis has been an important stratigraphic tool to delimit fluvial deposits geometries, and alluvial architecture evolution. Outcrops information of the Bauru Group from western Minas Gerais State (Triângulo Mineiro), northeastern of Mato Grosso do Sul, and southern Goias, allowed to elaborate models that shows the litossom geometries of the neo-cretaceous sequence. The faciological characteristics associated to downstream macroforms (DA Element), Sandy bars (SB Element), gravel bars and channels (GB and CH Elements) are indicating the paleoenvironment as low-sinuosity braided river dominated, associated to alluvial fan system. Paleocurrent data indicate that source area were mainly in the north and northeast of the Bauru Basin, in the Alto Paranaiba Uplift and Alkaline Complex of South Goias. The depositional characteristic has permitted to reconstruct the northern basin alluvial architecture, given important information about base level changes, sedimentation rate and accommodation space. Applying an alternative terminology to continental stratigraphic sequence, the evolution model of the neo-cretaceous alluvial sequence shows the high accommodation system tract to its lowest units (Aracatuba and Adamantina Formations), and low accommodation system tract to uppers (Uberaba and Marilia formations).