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http://hdl.handle.net/10773/13028
Title: | New U-Pb SHRIMP zircon ages for pre-variscan orthogneisses from Portugal and their bearing on the evolution of the Ossa-morena tectonic zone |
Author: | Cordani, U. G. Nutman, A. P. Andrade, A. S. Santos, J. F. Azevedo, M. do Rosário Mendes, M. H. Pinto, M. S. |
Keywords: | Cadomian orogeny Iberian Massif Ossa-Morena Zone U-Pb geochronology |
Issue Date: | 2006 |
Publisher: | Academia Brasileira de Ciências |
Abstract: | New SHRIMP U-Pb zircon ages for the Portalegre and Alcáçovas orthogneisses document a complex pre-Variscan history for the Iberian basement in Portugal. The available geochemical and geochronological data for the Alcáçovas orthogneiss (ca. 540 Ma) tend to favor its involvement in a Cadomian orogenic event. This is consistent with the development of an active continental margin setting at the end of the Proterozoic and supports a Gondwanan provenance for the Iberian crust. On the other hand, the Ordovician emplacement age obtained for the magmatic precursors of the Portalegre orthogneisses (497 ± 10 Ma) provides additional evidence for the occurrence of rift-related magmatic activity during the Lower Paleozoic. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/13028 |
DOI: | 10.1590/S0001-37652006000100013 |
ISSN: | 0001-3765 |
Appears in Collections: | DGeo - Artigos |
Files in This Item:
File | Description | Size | Format | |
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a13v78n1.pdf | documento principal | 435.11 kB | Adobe PDF | View/Open |
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