Structural and paleomagnetic evidence for non-rotational kinematics of the South Pyrenean Frontal Thrust at the western termination of the External Sierras (southwestern central Pyrenees)
Oliva Urcia, B. (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Casas, A. M. (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Pueyo, E. L. (Oficina de Proyectos de Zaragoza IGME. Departamento de Geología y Geofísica del subsuelo)
Pocoví Juan, Andrés (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)

Fecha:	2012
Resumen:	The definition of the structure and kinematics of the South-Pyrenean Frontal thrust, to the west of its westernmost outcrop in the External Sierras is the goal of this work. The methodology used is based on the construction and restoration of three balanced cross-sections. In addition to that, paleomagnetic analyses are applied to unravel possible vertical axis rotations linked to thrust kinematics. Stepwise thermal demagnetizations of 22 new sites together with previously published data from 25 sites (sampled in Bartonian-Priabonian sediments) define reliable primary directions in the region allowing for potential vertical axis rotations estimation. The comparison between the deformed and the pre-deformational states in the cross-sections agrees with the paleomagnetic data in that neither gradient of shortening, nor significant vertical axis rotations can be invoked to explain the along-strike changes of the main structures (folds and thrusts) linked to the South-Pyrenean Frontal thrust, west of the western termination of the External Sierras. Therefore, these changes are here interpreted as the result of a wedge thrust in the Paleozoic basement, whose displacements in transferred to the Mesozoic-Tertiary cover through the Upper Triassic detachment level. This non-rotational kinematics of deformation implies a change of deformational style with respect to the External Sierras, where clockwise vertical axis rotations and gradient of shortening linked to rotational kinematics are found to be controlled by the Upper Triassic detachment level.
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Non-rotational ; South-Pyrenean Frontal thrust ; Vertical Axis Rotations ; Gradient of shortening ; Balanced and restored cross-section ; Paleomagnetism
Publicado en:	Geologica acta, Vol. 10, Núm. 2 (June 2012) , p. 125-144, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/257169
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000001704
DOI: 10.1344/105.000001704

22 p, 1.6 MB

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