Crustal Imbrication in an Alpine Intraplate Mountain Range: A Wide-Angle Cross-Section Across the Spanish-Portuguese Central System
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DeFelipe, Irene; Ayarza, Puy; Palomeras, Imma; Ruiz, Mario; Andrés, Juvenal; Alcalde, Juan; Martínez Poyatos, David Jesús; González Lodeiro, Francisco; Yenes, Mariano; Elez, Javier; Pérez Cáceres, Irene; Torné, Montse; Carbonell, RamónEditorial
Wiley
Fecha
2022-07-14Referencia bibliográfica
DeFelipe et al. (2022) Crustal Imbrication in an Alpine Intraplate Mountain Range: A Wide-Angle Cross-Section Across the Spanish-Portuguese Central System. Tectonics, 10.1029/2021TC007143
Patrocinador
Ministry of Science, Innovation and Competitiveness through the Project CIMDEF (CGL2014-56548-P); Spanish Government and the University of Salamanca (Beatriz Galindo grant BEGAL 18/00090); Grant IJC2018-036074-I, funded by MCIN/AEI/10.13039/501100011033; Grants CGL2015-71692 (MINECO/ FEDER) and PID2020-118822GB-I00 (MCIN/AEI/10.13039501100011033)Resumen
Intraplate ranges are topographic features that can occur far from plate boundaries, the
expected position of orogens as described in the plate tectonics theory. To understand the lithospheric
structure of intraplate ranges, we focused on the Spanish-Portuguese Central System (SPCS), the most
outstanding topographic feature in the central Iberian Peninsula. The SPCS is an Alpine range that exhumes
Precambrian-Paleozoic rocks and is located at >200 km from the northern border of the Iberian microplate.
Here, we provide a P-wave velocity model based on wide-angle seismic reflection/refraction data of the central
SPCS (Gredos sector). Our results show: (a) a layered lithosphere characterized by three major interfaces:
Conrad, Mohorovicic, and Hales discontinuities, (b) an asymmetry of the crust-mantle boundary under the
SPCS, (c) the extent of the Variscan batholith forming the main outcrops of Gredos, and (d) the thinning of the
lower crust toward the south. This model suggests that the exhumation of the SPCS basement was driven by a
south-vergent thick-skinned thrust system, developed in the southern part of the SPCS and that promoted crustal
imbrication and a Mohorovicic discontinuity's offset under the SPCS. Thus, the deformation mechanisms of the
crust seem to be controlled by the presence of the late- to post-Variscan granitoids that assimilated the Variscan
mid-crustal detachment creating a new rheological boundary. This tectonic structure allowed the formation
of Alpine crustal-scale thrust systems that eased coupled deformation of the upper and lower crust, leading to
limited underthrusting of both crustal layers.