Discontinuidades del Cretácico medio en el margen septentrional de la Depresión Intermedia (Zubieta, Navarra).

Abstract

The "Central Depression" was a narrow deep-marine basin located on the northern Navarre (western Pyrenees), mainly filled with Upper Cretaceous calcareous flysch and inverted during Alpine Orogeny. The detailed study of an outcrop near the village o f Zubieta, in the northern margin of the basin, shows three unconformity surfaces dated Albian-Turonian. They successively separate a) underlayingjurassic limestones from lower/middleAlbian limestones (St), b) the latter limestones from Upper Albian siliciclastic flysch (SJ, and c) this flysch from Turonian marls and calcareous turbidites (S3). Synsedimentary tectonic pulses, that they creating a horst in the north o f the section and a composed graben in the south of this, are invoked to explain the stratigraphic succesion described. These pulses were probably related to the major Leitza fault, interpreted as the southern margin of the Early Cretaceous "Central Depression" subjected to sinistrai strike-slip movements.