Evolución del sistema lacustre de Artesa de Segre (Eoceno superior de NE de la Cuenca del Ebro)

The Artesa de Segre lacustrine system is aged uppermost Priabonian. This lacustrine basin is located in the backthrust of the southermost thrust of the Sierras Marginales Imbricate Fan. It is filled by alluvial deposits, during the uplifting of the thrust, and by lacustrine deposits during the quiet periods in the thrust movement. The complet infilling of the basin conforms a depositional sequence related to tectonism of the Sierras Marginales Imbricate Fan. The depositional sequence can be subdivided in five minor order cycles, and these cycles could also be divided in other high frequency cycles. The last units consist of a lower stretch with red shales and sandstones, deposited during arid and colder periods, with a low water column in the lake or in subaerial environments, and an upper lacustrine stretch with grey to white shales and sandstones, sedimented during humid and warmer periods, with a high global base level and the consequent expansion of the lake. These high frequency cycles would be Milankovitch or climatic cyles