The Yapeyu paleosurface : stratigraphific and paleoenvironmental signified in the evolution of superior cretaceous of Uruguay

The named Yapeyu paleosurface placed between Yapeyu and del Palacio Members of the Asencio Formations is anlalyzed in outcrops of the Pedro Chico, Gruta del Palacio and Cca. Arroyo Coquimbo localities. Herrein, its morphologic and paleoenvironmental features are considered to attribute an paleosoil origin for this. This paleosurface is indicative of an important break in the sedimentation and contain several indicators of paleoclimatic tropical and humid conditions. Following allostratigraphic schemes, the paleosurface represent the lower contact of the Asencio Formation constituting a new stratigraphic proposal. Finally, taking into account sedimentalogical features the alluvial origin by the conglomerates of del Palacio Member is rejected. (author)