Recent palaeostresses from striated pebbles related to fold development in a mountain front: the Prerif Ridges (Rif Cordillera, Morocco)
P. Ruano, K. Bargach, J. Galindo-Zaldívar, A. Chalouan, M. Ahmamou, 2006. "Recent palaeostresses from striated pebbles related to fold development in a mountain front: the Prerif Ridges (Rif Cordillera, Morocco)", Tectonics of the Western Mediterranean and North Africa, G. Moratti, A. Chalouan
Download citation file:
The southern mountain front of the Rif Cordillera (Morocco) provides impressive geological evidence of the most recent deformations related to the activity of the Eurasian-African plate boundary in the Western Mediterranean. In this region, striated and pitted pebbles are analysed from Pliocene-Quaternary rocks located in the southern front of the Prerif Ridges, which have been deformed by south-vergent folds of decametre to hectometre sizes. Striated and pitted pebbles represent a tectonic deformation structure which, although very scarce in nature, is revealed as one of the most complete for determining palaeostresses. In Jbel Trhat and Jbel Zerhoun of the Rif mountain front, north-south to NNW-SSE prolate compression stress ellipsoids are related to an initial stage of south-vergent fold development during the progressive tilting of conglomerate layers. Finally, oblate stress ellipsoids indicate extension parallel to the fold axes. The north-south trend of the determined compression is compatible with a tectonic setting where the NW-SE convergence of the Eurasian and African plates is modified by the westward motion of large crustal blocks such as the Alboran Domain or the southwestward motion of blocks in the Rif Cordillera.
Figures & Tables
This book provides an insight into the overall tectonic evolution of the Western Mediterranean region and North Africa. The tectonic setting of the region reflects a long-lived and complex evolution, mainly related to the Alpine Orogeny. This inheritance is expressed by an intricate pattern of arc-shaped mountain chains, the Alps, the Betic–Rif Cordilleras and the Apennine–Maghrebian belt, whose southern branches mark the present limit between the African and Eurasian plates. The volume covers the Maghrebian chains in North Africa, from Tunisia to Morocco and the Western and Central Mediterranean, from Spain to Italy from the pre-orogeric phases (Palaeozoic–Mesozoic) to the post-collisional neotectonic and Quaternary development. It includes both original research papers and syntheses dealing with the aspects of structural, sedimentary, metamorphic and marine geology.