RT Journal Article
T1 The last stages of the Avalonian–Cadomian arc in NW Iberian Massif: isotopic and igneous record for a long-lived peri-Gondwanan magmatic arc
A1 Andonaegui Moreno, María Del Pilar
A1 Arenas Martín, Ricardo
A1 Albert Roper, Richard
A1 Sánchez Martínez, Sonia
A1 Díez Fernández, Rubén
A1 Gerdes, Axel
AB The upper allochthonous units of NW Iberian Massif contain an extensive Cambrian magmatism (c. 500 Ma), covering felsic to mafic compositions. The magmatic activity generated large massifs of granitoids and gabbros, with calc-alkaline and tholeiitic compositions respectively. Petrological and geochemical features of these massifs are characteristic of volcanic arc. The plutons intruded siliciclastic sedimentary series deposited in the periphery of the West Africa Craton. U–Pb/Hf isotopic compositions of detrital zircon in the siliciclastic host series, indicate continental arc activity between c. 750 Ma and c. 500 Ma. It was characterized by a large variety of isotopic sources, including from very old continental input, even Archean, to the addition of a significant amount of juvenile mafic material. These isotopic sources experienced an extensive mixing that explains the composition and isotopic features (εHft from −50 until +15) of the represented Cambrian plutons. The Cambrian igneous rocks of the upper units of NW Iberia are related to the latest activity of the Avalonian–Cadomian arc. From the Middle Cambrian arc activity in the periphery of Gondwana was replaced by pronounced extension associated with the development of continental rifting, which finally led to separation of the microcontinent Avalonia. Subsequent drifting of Avalonia to the North caused progressive opening one of the main Paleozoic ocean, the Rheic Ocean.
PB Elsevier
SN Issn: 0040-1951 ;  Essn: 1879-3266
YR 2016
FD 2016-06
LK https://hdl.handle.net/20.500.14352/23607
UL https://hdl.handle.net/20.500.14352/23607
LA eng
NO Ministerio de Economía y Competitividad (MINECO)
DS Docta Complutense
RD 3 oct 2024