The role of major fault zones in controlling the geometry and spatial organization of structures in the Zagros Fold–Thrust Belt
Published:January 01, 2007
M. Sepehr, J. W. Cosgrove, 2007. "The role of major fault zones in controlling the geometry and spatial organization of structures in the Zagros Fold–Thrust Belt", Deformation of the Continental Crust: The Legacy of Mike Coward, A. C. Ries, R. W. H. Butler, R. H. Graham
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The present-day morphology of the Zagros Fold-Thrust Belt is dominated by magnificent exposures of NW-SE-trending folds. This mountain belt is also characterized by a series of belt-parallel and belt-oblique (transfer) fault zones. Not all the fault zones have a clear exposure at the surface because of the presence of thick incompetent overlying sedimentary successions, but they can be identified from a study of the present-day seismicity of the belt and by the spatial organization of the overlying folds. The folds are not often cross-cut by the faults but plunge towards, or are deflected and end against, these blind transfer fault zones. As a result, shortening is accommodated by different fold trains on either side of the fault. This decoupling in turn causes the step-like offset of the major, belt-parallel thrust zones and the related topographic elements. These offsets occur on all scales, from regional (e.g. across the Kazerun and Izeh fault zones) to local. These transfer faults-lateral ramps may be influenced by pre-existing structures or by facies boundaries, which in particular influenced the Zagros Basin in the Cretaceous. In addition to controlling sedimentation and the compartmentalization of deformation, these fault zones also act as paths of fluid migration, as indicated by the present-day concentration of oil seepages and thermal or sulphur springs.
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Deformation of the Continental Crust: The Legacy of Mike Coward
This Special Publication, in memory and celebration of the work of Professor Mike Coward, is about the deformation of the continental lithosphere. The collected papers discuss geometry, structural principles, processes and problems in a wide range of tectonic settings and thereby reflect the breadth of Coward's interests. They encompass the evolution of Precambrian basement gneiss terrains, the geometry and evolution of thrust systems, basement involvement and structural inheritance in basins, syn-orogenic extension, salt tectonics, the implication of structural evolution on hydrocarbon prospectivity and structural controls on mineralization. Examples are drawn from the Lewisian and Moine Thrust Belt of NW Scotland, the Italian Apennines, NW Himalayas, the Cyclades, Oman, Zagros Mountains, Colombian Cordillera, Carpathians, North Sea, offshore Brazil, regional studies of the Irumide Belt (central Africa), Taurus Mountains (Turkey), greater South America, and from the Witwatersrand Basin of South Africa and the Antler Orogeny of SW USA.