Marine influence in the Barreiras Formation, State of Alagoas, northeastern Brazil

摘要: Tidal processes were important for deposition of the Barreiras Formation located in northern Brazil, while correlatable deposits northeastern Brazil have been traditionally related to continental environments. Facies analysis southern Alagoas revealed that consists cross-stratified conglomerates and sandstones (facies Sx Cgx), compound Cx), heterolithic beddings H). A significant portion these occurs within channel morphologies displaying fining thinning upward successions. An abundance sedimentary features is comparable those from Brazilian counterpart. These include: tidal bundles; herringbone cross-stratification; with sandstone mudstone beds sharp contacts; ichnofossils mostly consisting Ophiomorpha nodosa, Skolithos Planolites. Altogether, point a marginal marine depositional setting dominated by processes, which are an estuarine system, interpretation also provided Brazil. The widespread occurrence unambiguous evidence now State Alagoas, leads argue early/middle Miocene worldwide transgression might left much more record along coast than currently regarded.