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http://hdl.handle.net/10773/13024
Title: | U-Pb zircon and monazite geochronology of Variscan magmatism related to syn-convergence extension in Central Northern Portugal |
Author: | Valle Aguado, B. Azevedo, M. R. Schaltegger, U. Martínez Catalán, J. R. Nolan, J. |
Keywords: | Collision granites Exhumation Extension Iberian Variscan Belt Transcurrent tectonics U-Pb dating Geochronology Hercynian orogeny Magmatism Iberian Massif Iberian Peninsula Portugal |
Issue Date: | 2005 |
Publisher: | Elsevier |
Abstract: | The Viseu area is located in the Central Iberian Zone of the Iberian Variscan Belt and hosts numerous post-thickening, collision-related granitoids intruded into upper and middle crustal levels. The present paper reports high precision U-Pb zircon and monazite ages for four plutons of the Viseu area: The syn-kinematic granitoids of Maceira (314±5 Ma), Casal Vasco (311±1 Ma) and Junqueira (307.8±0.7 Ma) and the late-kinematic biotite monzogranites of Cota (306±9 Ma). This points to a synchronous emplacement of the different syn-kinematic plutons shortly followed by the intrusion of the late-kinematic granites and shows that the Upper Carboniferous plutonism occurred within a short time span of ca. 10 million years. The ascent of granite magmas took place after an extensional tectonic event (D2) and is coeval with dextral and sinistral crustal-scale transcurrent shearing (D3). Field and petrographical evidence suggest a narrow time-span between peak T metamorphic conditions and the intrusion of granitic melts which implies very fast uplift rates accommodated through active tectonic exhumation. Magma compositions evolve through time, reflecting an increasing involvement of mid-crustal sources and the underplating effect of an upwelling asthenospheric mantle at the base of a thinning and stretching continental crust. © 2005 Elsevier B.V. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/13024 |
DOI: | 10.1016/j.lithos.2004.12.012 |
ISSN: | 0024-4937 |
Appears in Collections: | DGeo - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Lithos2005.pdf | documento principal | 645.36 kB | Adobe PDF | View/Open |
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