Respuesta sedimentaria a factores alocíclicos durante el Eoceno en Cubillos (Zamora, oeste de la Cuenca del Duero)

Abstract

To the northeast of Zamora's city they are materials related with the oldest lacustrine sediments in the tertiary Duero Basin. The aim of this paper is the sedimentologic and stratigraphie study of these materials, located to the west of the Duero Basin, around Cubillos, Zamora. It is sought to determine the evidences of the paleogeographic evolution through the sedimentary registration of the materials and how these configure the answer to the changes in the alocyclic factors (tectonic and climate) along the Eocene in the study area. The study of the materials (Cubillos Unit) allows to establish a sedimentary evolution constituted by five stages, which consists of different paleogeographic phases, beginning with fluvial sedimentation coming from different source areas (southwest and northwest), deltaic gradation and a expansive lacustrine system and slight salinity and that it seems to be located in a depressed area originated by flaws conjunction. Later on, it exists a gradation of another fluvial system of moderate sinuosity coming from the N and NE. Everything seems to indicate that the climate and the tectonic have influenced significantly in the sedimentation of the Cubillos Unit, where the climate controlled the dynamics of the rivers and the evolution of the lacustrine system and the tectonic controlled the sinking of the lacustrine system and the source areas reactivation.