Edades del basamento pre-varisco en IberiaHerencia Icartiense, Grenville y Cadomiense en rocas del Complejo Olio de Sapo (NW de España). Estudio geocronológico mediante ablación láser
- Gutiérrez Alonso, Gabriel
- Jenner, G.A.
- Trubett, M.
- Fernández Suárez, J.
ISSN: 0211-8327
Ano de publicación: 1998
Volume: 34
Páxinas: 103-121
Tipo: Artigo
Outras publicacións en: Studia geologica salmanticensia
Resumo
Zircons from an Ordovician volcano-sedimentary-igneous complex in NW Iberia were dated using the Laser Ablation-ICP-MS technique. U-Pb results indicate the existence of at least three pre-Paleozoic events of crustal growth in NW Iberia. The oldest event (ca 1,9-2 Ga) corresponds to the Icartian-Eburnean event which is also recognised in other areas of the European Variscides. The second event (dated at ca 1,1 Ga) reveals the existence of a Grenville-Sunsas age basement in Iberia. The third event, dated at ca 550-625 Ma confirms the widespread presence of a Cadomian- Avolonian basement in Iberia. These data provide new ideas for paleogeographic reconstructions and petrogenetic modeling of Neoproterozoic and Paleozoic igneous rocks in Iberia and neighbouring areas of the European Variscides. The presence of a Grenville age lower crustal component sheds new lighton the interpretation Nd isotopic signatures of I-type Cadomian and Variscan granitoids, and suggests a position of Iberia close to the Avalonia and Carolina terranes during Cadomian-Avalonian times.