Evolución sedimentaria de la Cuenca Surpirenaica Oriental durante el Eoceno

Abstract

Two main phases can be recognized in the Eastern Eocene South-Pyrenean Foreland basin. The first one, which includes the Lower Ypresian (Ilerdian) to Upper Lutetian sedimentary package, is characterized by an asymmetrical basin fillproduced as a consequence of the different tectonic activity of both basin margins. In the foreland margin, a carbonatic sedimentation took place creating an stepped onlap margin geometry. In the orogenic margin, the terrigenous influx from the orogenic belt developed successive progradational clastic wedges. Three Depositional Sequences can be recognized including coetaneous retrogradational carbonate depositional systems in the foreland margin with progradational siliciclastic systems in the active margin. The forelandward advance of the orogenic belt produces, progressively, the drowning of the foreland margin. As a consequence of this, the active rnargin clastic wedge progrades onlapping the drowned distal carbonate margin facies. The second phase, which includes Bartonian and Lower-Middle Priabonian sediments, is characterized by the introduction of a second active basin margin, known as Catalanid margin. Symmetrical siliciclastic wedges from the Pyrenean and Catalanid margin shape the basin fill. One Depositional Sequence, including two transgressive systems tract followed by two regressive systems tract, are recognized in this phase.