Abstract
A tectonic study of the area northwest of Sierra de la Demanda (Spain) revealed Tertiary orogenic phases represented by overlaps and overturnings. Towards the northern border, the Cambrian overrides Carboniferous, Triassic and Jurassic formations; the Carboniferous-Triassic units appear overturned under the Cambrian; and the Jurassic formations are affected locally by a system of dislodged slices of nappes associated with imbricate basement rocks. Two major directions of deformation suggest the presence of two successive orogenic phases. The first phase, older than the Oligocene conglomerates, folded the units above the basement in a NW-SE direction, parallel to the north oriented horst in the basement complex. In the post-Oligocene phase NE-SW imbrication affected the conglomerates as well as the basement and overlying units.