A revised Ordovician age for the Sisargas orthogneiss, Galicia (Spain). Zircon U-Pb ion-microprobe and LA-ICPMS dating Talavera Rodríguez, Cristina Bea Barredo, Fernando González Montero, Pilar Whitehouse, Martin U-Pb dating Zircon Sisargas orthogneiss Iberian Massif The Sisargas orthogneiss is located in the Schistose Domain of the Galicia Trás-Os-Montes Zone. It has previously been dated by Allegret and Iglesias (1987) who reported an U-Pb upper intercept at 570 ± 14 Ma, considered to be the crystallization age. For this reason, the Sisargas orthogneiss has traditionally been considered one of the oldest magmatic rocks of the Central Iberian Zone. However, new SIMS and LA-ICPMS data reveal that it crystallized at 479 ± 7 Ma and contains zircons with abundant pre-magmatic cores with ages clustering at 585 ± 15 Ma. This suggests that the Sisargas orthogneiss derives from the melting of a Pan-African protolith. 2014-06-02T08:35:40Z 2014-06-02T08:35:40Z 2008 info:eu-repo/semantics/article Talavera, C.; et al. A revised Ordovician age for the Sisargas orthogneiss, Galicia (Spain). Zircon U-Pb ion-microprobe and LA-ICPMS dating. Geologica Acta, 6(4): 313-317 (2008). [http://hdl.handle.net/10481/32076] 1695-6133 1696-5728 http://hdl.handle.net/10481/32076 10.1344/105.000000259 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Universidad de Barcelona; Instituto de Ciencias de la Tierra Jaume Almera