Kinematic evolution of the eastern Tethyan Himalaya: constraints from magnetic fabric and structural properties of the Triassic flysch in SE Tibet
Borja Antolín, Erwin Appel, Chiara Montomoli, István Dunkl, Lin Ding, Richard Gloaguen, Rachida El Bay, 2011. "Kinematic evolution of the eastern Tethyan Himalaya: constraints from magnetic fabric and structural properties of the Triassic flysch in SE Tibet", Kinematic Evolution and Structural Styles of Fold-and-Thrust Belts, J. Poblet, R. J. Lisle
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Anisotropy of magnetic susceptibility (AMS) combined with structural analysis are used in this work with the aim to characterize the tectonic evolution of the Triassic flysch within the eastern Tethyan Himalaya Thrust Belt in SE Tibet. The attitude of the magnetic foliation and lineation are concordant with the planar and linear structures of tectonic origin defined by the preferred orientation of the iron-bearing silicates. Two different tectonic domains can be defined: (a) the southern domain is controlled by the Eohimalayan tectonic foliation (S1) recorded in the magnetic foliation which trends east–west and dips to the north; (b) the northern domain is dominated by the Neohimalayan magnetic foliation with WNW–ESE strike and dips to the south opposite to the vergence of the main structures. A slightly prolate magnetic ellipsoid has been found in between the two domains recording the intersection of S1 and the subtle development of the S2 tectonic foliation. Hinterland propagation of the deformation lead to the Great Counter backthrust generation, pointed out by the SSW steeply plunging magnetic lineation. Furthermore different orientations of magnetic foliation may indicate an Early Miocene c. 20° clockwise vertical-axis rotation.
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Fold-and-thrust belts occur worldwide, have formed in all eras of geological time, and are widely recognized as the most common mode in which the crust accommodates shortening. Much current research on the structure of fold-and-thrust belts is focused on structural studies of regions or individual structures and on the geometry and evolution of these regions employing kinematic, mechanical and experimental modelling. In keeping with the main trends of current research, this title is devoted to the kinematic evolution and structural styles of a number of fold-and-thrust belts formed from Palaeozoic to Recent times. The papers included in this book cover a broad range of different topics, from modelling approaches to predict internal deformation of single structures, 3D reconstructions to decipher the structural evolution of groups of structures, palaeomagnetic studies of portions of fold-and-thrust belts, geometrical and kinematical aspects of Coulomb thrust wedges and structural analyses of fold-and-thrust belts to unravel their sequence of deformations.