RT info:eu-repo/semantics/article
T1 Gravity and magnetic anomalies in the allochthonous Órdenes Complex (Variscan belt, northwest Spain): Assessing its internal structure and thickness
A1 Martínez Catalán, José R. .
A1 Álvarez Lobato, Fernando .
A1 Pinto, Victor .
A1 Gómez Barreiro, Juan .
A1 Ayarza, Puy .
A1 Villalaín Santamaria, Juan José
A1 Casas, Albert
K1 Órdenes Complex
K1 NW Iberia
K1 Variscan Belt
K1 geophysical modeling
K1 Paleontología
K1 Paleontology
K1 Magnetismo
K1 Magnetism
AB The Órdenes Complex is the largest Variscan allochthonous structure of NW Iberia, and preserves the suture of a long-standing Paleozoic ocean, probably the Rheic. Gravity and magnetic data, the latter specifically acquired on land for this study, show that the complex occupies the core of an open synform with a maximum depth of 9–10 km, which contrasts with the flat geometry of the lower crust and Moho discontinuity beneath. The maximum depth reached by the ophiolitic rocks marking the suture is around 7 km. The allochthonous units formed by basic and ultrabasic rocks are lens-shaped in section, and occur not only at the periphery of the complex, but form wide ribbons trending NE-SW to N-S. The Bouguer anomaly related with the longest of them, the Fornás Unit, previously used to support an autochthonous interpretation of the complexes, is modeled as a rootless, massive amphibolite body with a maximum thickness of 6 km located at the downthrown block of a large normal fault cutting across previous thrust faults and extensional detachments. The main magnetic anomalies are associated with ultrabasic rocks cropping out in the NW and SE, but a weak, wide anomaly in the central part of the complex is related with one or more thin layers of amphibolite partly mineralized with massive sulphides. The weakly arcuate geometry of this anomaly and of the Bouguer anomaly caused by the Fornás Unit may reflect the NE flank of the Central Iberian arc, an orocline whose core is occupied by the allochthonous complexes.
PB Wiley
SN 0278-7407
YR 2012
FD 2012-10
LK http://hdl.handle.net/10259.4/2562
UL http://hdl.handle.net/10259.4/2562
LA eng
NO FEDER, Ministerio de Ciencia e Innovación (Ramón y Cajal)
DS Repositorio Institucional de la Universidad de Burgos
RD 26-abr-2024