Resumen de Arquitectura deposicional de la Unidad Omells (Sistema Lacustre de les Garrigues, Oligoceno inferior del E de la Cuenca del Ebro)
Eudald Maestro Maideu, A. Bosch, Nestor Chamorro, Lluís Gibert Beotas, Sara Figueras Vila, J.A. Núñez, G. Rivas, J. Sancho
During the middle Priabonian, the eastern Ebro foreland basin became an endhorreic basin containing a lacustrine system in the central areas, which were bordered by alluvials coming from the surrounding chains: the Pyrenees and the Catalan Coastal Ranges in the study area context. The studied area belongs to "les Garrigues" lacustrine system (lower OUgocene), in the southeastern Ebro basin. The Omells unit, the study subject in this work, constitutes the base of this system. Within the Omells unit different orders of climatic changes are recorded by means of a distinctive cyclic stacking pattern, which consist in three elements. The lower part is formed by a south-derived (Catalan Coastal Range) fluvio-alluvial reddish stretch; the intermediate stretch is made by deltaic lacustrine deposits (with the same source area); finally, lacustrine limestones characteristically form the uppermost stretch. The stacking pattern is recording the cyclic variations of climate and thus, the base-level variations of the lake. The base of the cycle may point to a dry and cool climate merging upwards into humid and warm conditions. In the latter the lake was gentlely expanded with very high basin coverage.
