%0 Journal Article
%A Sánchez Martínez, Sonia
%A Arenas Martín, Ricardo
%A Gerdex, Axel
%A Castiñeiras García, Pedro
%A Potrel, Alain
%A Fernández Suárez, Javier
%T Isotope geochemistry and revised geochronology of the Purrido Ophiolite(Cabo Ortegal Complex, NW Iberian Massif): Devonian magmatism with mixedsources and involved Mesoproterozoic basement
%D 2011
%@ 0016-7649
%U https://hdl.handle.net/20.500.14352/42025
%X In the Purrido Ophiolite (Cabo Ortegal Complex), new U–Pb zircon dating of the amphiboliteG03-8 (by laser ablation inductively coupled plasma mass spectrometry) confirms the existence of a dominantMesoproterozoic zircon population with a refined age of 1155  14 Ma. However, the U–Pb zircon dating oftwo more amphibolite samples (by sensitive high-resolution ion microprobe) has provided new ages of395  3 Ma and 395  2 Ma, respectively, interpreted as the crystallization age. Hf isotope data for zirconshow that most of the Devonian zircons crystallized from a juvenile depleted mantle source. TheMesoproterozoic zircons have relatively juvenile Hf isotopic composition reflecting some influence of an oldercomponent. A few Devonian zircon crystals show evidence of mixing with an older component represented bythe Mesoproterozoic zircons. The whole-rock Sm–Nd isotope data indicate an important heterogeneity in thecomposition of the Purrido amphibolites, only compatible with the generation of their protoliths from twosources. We interpret these puzzling data as resulting from the mixing of a Devonian mantle-derived magmawith a Mesoproterozoic basement. These new data provide new perspectives in the interpretation of the mostcommon ophiolites across the Variscan suture in Europe.
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