%0 Journal Article
%A Castiñeiras García, Pedro
%A Navidad Fernández de la Cruz, Marina
%A Liesa Torre Marín, Montserrat
%A Carreras, Jordi
%A Casas Tuset, Josep María
%T U–Pb zircon ages (SHRIMP) for Cadomian and Early Ordovician magmatism in theEastern Pyrenees: New insights into the pre-Variscan evolution of the northernGondwana margin
%D 2008
%@ 0040-1951
%U https://hdl.handle.net/20.500.14352/49776
%X New geochronological data from low- to medium-grade metamorphic areas of the Eastern Pyrenees (Canigó,Roc de Frausa and Cap de Creus massifs) confirm the presence of two significant pre-Variscan igneous events:Ediacaran–Early Cambrian and Early Ordovician. The Ediacaran–Early Cambrian (580–540 Ma) magmatism ischaracterized by metavolcanic plagioclasic gneisses (metatuffs) coeval with sedimentation and by sheets ofgranitic orthogneisses emplaced in the lower part of the metasedimentary series. In the Canigó and Roc deFrausa massifs, the metatuffs are spatially associated with metabasites. Both lithologies occur as massivelayers of lava flows, discontinuous lense-shaped, subvolcanic, gabbroic bodies or volcanoclastic tuffsinterbedded in the lower and middle part of the pre-Upper Ordovician metasedimentary succession. Thismagmatism is bimodal and has a tholeiitic and calc-alkaline affinity. The granitic orthogneisses representthick laminar intrusions of subaluminous and aluminous composition. Early Ordovician (475–460 Ma)magmatism is represented by laccoliths of aluminous granitic orthogneisses emplaced in the middle part ofthe pre-Upper Ordovician succession.These geochronological data reveal the existence of an Ediacaran metasedimentary sequence and Cadomianmagmatism in the Pyrenees and allow their correlation along the Eastern Pyrenean massifs. The data alsoshow ages ranging from Neoproterozoic to Early Ordovician of the large bodies of granitic orthogneisses thatintruded into the series at different levels. Both events represent the final stages of the Cadomian orogenyand its transition to the Variscan cycle in the Eastern Pyrenees. A Cambrian rifting event linking both cycleshas not been identified in the Pyrenees to date.Our findings provide a better fit for the pre-Variscan sequences of the Pyrenees with those of the IberianMassif and allow their comparison with other pre-Variscan massifs in Europe.
%~