%0 Journal Article
%A Fernández Suárez, Javier
%A Díaz García, Florentino
%A Jeffries, Teresa E.
%A Arenas Martín, Ricardo
%A Abati Gómez, Jacobo
%T Constraints on the provenance of the uppermost allochthonousterrane of the NW Iberian Massif: inferences from detritalzircon U–Pb ages
%D 2003
%@ 0954-4879
%U https://hdl.handle.net/20.500.14352/57761
%X Insight into the origin and pre-orogenic palaeogeographicallinks of terranes involved in the assembly of collisionalmountain belts is fundamental to the understanding of orogenicprocesses. Here we address the provenance and possibletectonic settings of the uppermost allochthonous terrane ofthe NW Iberian Variscan Belt through a 213-nm Laser AblationICP-MS study of U–Pb ages of detrital zircons. The age groups ofzircons from greywackes in this terrane (c. 480–610, 1900–2100,2400–2500 Ma) and the lack of Mesoproterozoic zircons suggestan origin in a Neoproterozoic – Early Palaeozoic peri-Gondwanan realm along the periphery of the west Africancraton. It is further inferred that the greywackes weredeposited in the periphery of a crustal unit that had beendetached from the Gondwanan margin in relation to theopening of the Rheic ocean in Cambro-Ordovician times. Thisterrane was thrusted back upon the Gondwanan margin duringthe course of the Variscan collision and closure of theintervening ocean.
%~