Structure of an inverted basin from subsurface and field data : the Late Jurassic- Early Cretaceous Maestrat Basin (Iberian Chain)
Nebot Miralles, Marina (Universitat de Barcelona. Departament de Geodinàmica i Geofísica)
Guimerà, Joan (Universitat de Barcelona. Departament de Geodinàmica i Geofísica)

Data:	2016
Resum:	The Maestrat Basin experienced two main rifting events: Late Permian-Late Triassic and Late Jurassic-Early Cretaceous, and was inverted during the Cenozoic Alpine orogeny. During the inversion, an E-W-trending, N-verging fold-and-thrust belt developed along its northern margin, detached in the Triassic evaporites, while southwards it also involved the Variscan basement. A structural study of the transition between these two areas is presented, using 2D seismic profiles, exploration wells and field data, to characterize its evolution during the Mesozoic extension and the Cenozoic contraction. The S-dipping Maestrat Basement Thrust traverses the Maestrat Basin from E to W; it is the result of the Cenozoic inversion of the lower segment-within the acoustic basement-of the Mesozoic extensional fault system that generated the Salzedella Sub-basin. The syn-rift Lower Cretaceous rocks filling the Salzedella Sub-basin thicken progressively northwards, from 350m to 1100m. During the inversion, a wide uplifted area-40km wide in the N-S direction-developed in the hanging wall of the Maestrat Basement Thrust. This uplifted area is limited to the north by the E-W-trending Calders monocline, whose limb is about 13km wide in its central part, dips about 5ºN, and generates a vertical tectonic step of 800-1000m. We interpreted it as a fault-bend fold; therefore, a flat-ramp-flat geometry is assumed in depth for the Maestrat Basement Thrust. The northern synformal hinge of the Calders monocline coincides with the transition from thick-skinned to thin-skinned areas. The vast uplifted area and the low-dip of the monocline suggest a very low-dip for the basement ramp, rooted in the upper crust. The Calders monocline narrows and disappears laterally, linking to the outcrop of the Maestrat Basement Thrust. The evaporitic Middle Muschelkalk detachment conditioned the structural style. Some salt structures are also related to it; they developed during the Late Triassic extension, as deduced from the Keuper seismic reflectors that onlap the folded Upper Muschelkalk and form growth strata above some basement normal faults.
Drets:	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, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Basin inversion ; Fault-bend fold ; Vertical tectonic step ; Low-dip ramp ; Salt flow
Publicat a:	Geologica acta, Vol. 14 Núm. 2 (June 2016) , p. 155-177 (Articles) , ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/310443
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2016.14.2.5
DOI: 10.1344/GeologicaActa2016.14.2.5

23 p, 9.1 MB

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