RT Journal Article
T1 40Ar/39Ar laserprobe dating of mylonitic fabrics in a polyorogenic terrane ofNW Iberia
A1 Gómez Barreiro, Juan
A1 Wijbrans, Jan R.
A1 Castiñeiras García, Pedro
A1 Martínez Catalán, José R.
A1 Arenas Martín, Ricardo
A1 Díaz García, Florentino
A1 Abati Gómez, Jacobo
AB The tectonothermal evolution of a polyorogenic terrane in the Variscan belt of NW Spain has beenconstrained by 40Ar/39Ar laserprobe incremental heating experiments on mylonitic fabrics developed in majorstructures. Transitional levels between HP–HT and IP upper units in the O´ rdenes Complex wheremetamorphic and structural records demonstrate two cycles of burial and exhumation were selected for dating.Two groups of ages have been defined: (1) Silurian–Early Devonian, obtained from mylonites of the Forna´sextensional detachment, here considered as the minimum age for the start of tectonic exhumation of the HP–HT units and an upper age-limit for the HP–HT event itself; (2) Early to Mid-Devonian, from structuresrelated to the Variscan convergence in the area, which include top-to-the-east thrusts and extensionaldetachments. A single, younger Carboniferous age obtained from the uppermost allochthonous sequencespossibly reflects the final stages of emplacement of the allochthonous complexes. Our data indicate apolyorogenic character for a part of the Iberian allochthonous complexes, including Variscan (sensu stricto)and Early Variscan convergence, as well as an older, Early Palaeozoic cycle.
PB Geological Society of London.
SN 0016-7649
YR 2006
FD 2006
LK https://hdl.handle.net/20.500.14352/49778
UL https://hdl.handle.net/20.500.14352/49778
LA eng
DS Docta Complutense
RD 10 abr 2025