%0 Journal Article
%A Antón López, Loreto
%A Muñoz Martín, Alfonso
%A Vicente Muñoz, Gerardo De
%T Alpine paleostress reconstruction and active faultingin western Iberia
%D 2010
%@ 1896-1517
%U https://hdl.handle.net/20.500.14352/41768
%X The study of intraplate tectonics is crucial for understanding the deformation within plates, far from active plateboundaries and associated stress transmission to the plate interiors. This paper examines the tectonic evolutionof the Variscan basement at the western margin of the Cenozoic Duero basin. Located east of the VilariçaFault System in NW Iberia, this intraplate zone is a relatively flat but elevated area with an intense NNE-SSWtrending fault system and associated moderate seismicity. Although the area has played an important role inthe Duero basin configuration, its Alpine to present-day tectonic evolution has not been well constrained.In order to characterize the successive paleostress fields, 1428 pairs of fault-striae were measured at 56 sitesand two focal mechanisms were used. Stress inversion methods have been applied to analyze paleostressregimes. Results show the existence of three dominant maximum horizontal stress (Shmax) trends: N-S,NE-SW and E-W. Relative and absolute dating of the activated faults for each Shmax shows that the clearlypredominant N-S paleostress field in the zone has been active since the Oligocene up to the present day; whilea NE-SW stress field is found to have been active during the Cretaceous and an older E-W paleostress fieldwas active in the earlier Alpine cycle (Late Triassic).
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