The Diversity of Late Neogene Sedimentary Basins Generated by Wrench Faulting in the Eastern Betic Cordillera, Se Spain

Abstract

In this paper, we review the types of sedimentary basins which are generated by wrench faulting with particular reference to the Late Neogene Eastern Betic Shear Zone, a well‐documented segment of the Trans‐Alboran Shear Zone. The general characteristics of this wrench “corridor” are described, including the role of inherited structures. The diversity of basin types is emphasised, as is the coexistence of basins which developed under compressional or extensional regimes. Pull‐apart basins do not appear to be the most widespread type of basin in the Eastern Betic Shear Zone. Rather, compressional “groove‐shaped synclines” which run parallel to master strike‐slip faults (regardless of their orientation or direction of movement) are more typical structures. They are characterised by intense synsedimentary deformation and reworking of sediments, depositional processes being dominated by gravity flows. The basins are relatively short‐lived and generally undergo structural inversion. Sedimentary basins also form in extensional areas, most significantly in the triangular zones which occupy the extensional quadrant of a pseudo‐ conjugate strike‐slip fault system. In the Eastern Betics, it appears that compressional basins are more efficient than extensional basins in terms of their subsidence and sedimentation rates, the thickness of the clastic fill, and the intensity of synsedimentary deformation. Compressional basins may therefore be the more favourable with respect to potential hydrocarbon accumulations.

Evidence for Late Messinian seismites, Nijar Basin, south‐east Spain

“…Previous studies have already established the fundamental influence of active tectonics on shaping the Nijar and adjoining basins during this latest Miocene interval (Montenat et al, 1987a,b, Coppier et al, 1990Stapel et al, 1996;Huibregtse et al, 1998;Montenat & Ott d'Estevou, 1999;Jonk & Biermann, 2002;de Larouzière et al, 1988;Fortuin & Krijgsman, 2003;Martinez-Diaz & Hernandez-Enrile, 2004). A link between most of the sediment deformation features discussed here and seismic activity therefore seems plausible.…”

“…Fault kinematic studies indicate that the morphology of the internal Betic basins was largely controlled by the re-orientation of regional compressive stresses and their interaction with the main faults crossing the SE Iberian Peninsula (Montenat et al, 1987a,b;Coppier et al, 1990;Stapel et al, 1996;Huibregtse et al, 1998;Montenat & Ott d'Estevou, 1999;Jonk & Biermann, 2002). Three major strike-slip zones are important ( Fig.…”

The 11 May 2011 earthquake at Lorca (SE Spain) viewed in a structural-tectonic context

“…Vissers et al, 1995). Meanwhile, a strike-slip origin of the basins as suggested by Montenat et al (1987) andDe Larouzière et al (1988) seems at variance both with recent structural studies of the underlying Betic basement and with the overall basin and fault geometry. In a recent study of the structure and kinematics of the Alhama de Murcia and Crevillente faults and of the synsedimentary structures in the late Miocene basin sediments, Meijninger and Vissers (2006) Along the southern margin of the Lorca basin and along the Sierra de las Estancias southwest of Lorca, the Alhama de Murcia fault is a morphologically sharp, NE trending linear structure ( Fig.…”

“…This zone of prominent faults, characterized by marked seismicity (e.g. Stich et al, 2003), continues into the Alboran Sea (Montenat et al, 1987;De Larouzière et al, 1988;Montenat and Ott d'Estevou, 1990) in a belt of equally high seismic activity (Fig. 1, inset).…”

“…Current tectonic interpretations of these basins vary, from late-orogenic extensional structures in response to transient stages in the west Mediterranean lithosphere structure (e.g. Platt and Vissers, 1989;Lonergan and White, 1997;Spakman and Wortel, 2004), to a pull-apart origin associated with strike-slip movements along the NE trending network of prominent faults interpreted as major strike-slip faults (Montenat et al, 1987;De Larouzière et al, 1988;Ott d'Estevou, 1990, 1999). Late-orogenic extension in the western Mediterranen region has been interpreted in terms of convection (Platt and Vissers, 1989), lithospheric delamination (García Dueñas et al, 1992), and subduction rollback followed by slab detachment (Morley, 1993;Lonergan and White, 1997;Gutscher et al, 2002;Spakman and Wortel, 2004).…”