Características estratigráficas y sedimentológicas del "Garumniense" en el sector de Ager (Pre-Pirineo, Lleida)

Abstract

The depositional sequences of the Paleogene non-marine deposits in the Ager basin show the vertical succession of lacustrine sediments (Massana Formation), fluvial and floodplain deposits (Figuerola Fm), basin-wide lacustrine sediments (Milla Fm) and different successions of lacustrine-palustrine, floodplain, fluvial, sabkha and tidal deposits (Perauba Complex). These different sedimentary environments where developed during Upper Maastrichtian-Lower Paleogene time span. The fossil assemblages suggest that the K/T event occurred during the sedimentation of one of these sedimentary environments. Formerly it was assumed that the KJí boundary event was strictly related to a particular carbonate leve1 (Milla Fm), but now this event is related to the deposition of floodplain and fluvial sediments at the Upper portion of the Figuerola Fm. Accordingly with the new paleomagnetic and paleontologic data, the disappearance of the cretaceous charophytes and dinosaurs seems to have occurred in the studied area about two million years before K/T boundary event.