Secuencias de alta y baja frecuencia en el Eoceno superior del este de la Cuenca del Ebro

From the uppermost Priabonian to Oligocene, the Ebro basin losses the connection with the open sea, being an endorreic basin. The active tectonism at the margins of the basin (Pyrenees at the N, and Catalan Ranges at the S) provides the formation of Alluvial fans that evolved to lacustrine systems in the centre of the basin. The most ancient lacustrine system in the Ebro basin is called "La Noguera Lacustrine System", and ages uppermost Priabonian. It consists of Barbastro Gypsum Fm, Tora limonites Fm and Castelltallat Limestone Fm . The two last formations, called in present work as Unit 7 and Unit 2, were deposited during 0,9 to I m.y. Unit 7 represents deeper lacustrine cycles and Unit 2 represents an important and general retraction of the lacustrine system. High frequency cycles can be differentiated. These cycles can be associated to orbital cycles described by Milankovitch. Dos cycles have a very close stacking patterns in between, with the terrigenous deposits in the base and carbonate deposits in the top.