Extensional attenuation of the Malaguide and Alpujarride thrust sheets in a segment of the Alboran basin folded during the Tortonian (Lorca area, Eastern Betics)

Abstract

Two systems of low-angle normal faults (LANFs), formed by listric faults and detachments, superimposed on a previous thrust stack, attenuate the upper allochthonous units of the Alboran Crustal Domain, particularly the Malaguide and Alpujarride units, which presently constitute the basement of the Lorca basin (Eastern Betics). The structurally highest detachment separates the Upper Malaguide units from the Lower Malaguide units, and has a north-northwest transport sense. This detachment is tilted by listric normal faults, with west-southwest transport, which seat on a fault zone with ramp-flat geometry in the Alpujarride complex. The LANFs have thinned the Alpujarride and Malaguide complexes of the Alboran Crustal Domain, contributing during the Lower-Middle Miocene to the formation of the 'Palaeo-Alboran' basin, and have been later exhumed from below the sedimentary cover of the Lorca Basin, in the core of an Upper-Miocene anticline. To cite this article: G. Booth-Rea et al., C. R. Geoscience 334 (2002) 557-563.  2002 Academie des sciences / Editions scientifiques et medicales Elsevier SAS