caa a22 4500 445390042 CHVBK 20180317143043.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s00710-010-0142-6 doi (NATIONALLICENCE)springer-10.1007/s00710-010-0142-6 U-Pb isotopic ages and Hf isotope composition of zircons in Variscan gabbros from central Spain: evidence of variable crustal contamination [Elektronische Daten] [Carlos Villaseca, David Orejana, Elena Belousova, Richard Armstrong, Cecilia Pérez-Soba, Teresa Jeffries] Ion microprobe U-Pb analyses of zircons from three gabbroic intrusions from the Spanish Central System (SCS) (Talavera, La Solanilla and Navahermosa) yield Variscan ages (300 to 305Ma) in agreement with recent studies. Only two zircon crystals from La Solanilla massif gave slightly discordant Paleoproterozoic ages (1,848 and 2,010Ma). Hf isotope data show a relatively large variation with the juvenile end-members showing ɛHfi values as high as +3.6 to +6.9 and +1.5 to +2.9 in the Navahermosa and Talavera gabbros, respectively. These positive ɛHfi values up to +6.9 might represent the composition of the subcontinental mantle which generates these SCS gabbros. This ɛHfi range is clearly below depleted mantle values suggesting the involvement of enriched mantle components on the origin of these Variscan gabbros, and is consistent with previous whole-rock studies. The presence of zircons with negative ɛHfi values suggest variable, but significant, crustal contamination of the gabbros, mainly by mixing with coeval granite magmas. Inherited Paleoproterozoic zircons of La Solanilla gabbros have similar trace element composition (e.g. Th/U ratios), but more evolved Hf-isotope signatures than associated Variscan zircons. Similar inherited ages have been recorded in zircons from coeval Variscan granitoids from the Central Iberian Zone. Granitic rocks have Nd model ages (TDM) predominantly in the range of 1.4 to 1.6Ga, suggesting a juvenile addition during the Proterozoic. However, Hf crustal model ages of xenocrystic Proterozoic zircons in La Solanilla gabbro indicate the presence of reworked Archean protoliths (TDM2 model ages of 3.0 to 3.2Ga) incorporated into the hybridized mafic magma. Springer-Verlag, 2010 Villaseca Carlos Departamento de Petrología y Geoquímica-Instituto de Geología Económica. Centro mixto UCM-CSIC, Complutense University of Madrid, 28040, Madrid, Spain aut Orejana David Departamento de Petrología y Geoquímica-Instituto de Geología Económica. Centro mixto UCM-CSIC, Complutense University of Madrid, 28040, Madrid, Spain aut Belousova Elena GEMOC, Department of Earth and Planetary Sciences, Macquarie University, 2109, Sydney, NSW, Australia aut Armstrong Richard Research School of Earth Sciences, Australian National University, Canberra, Australia aut Pérez-Soba Cecilia Departamento de Petrología y Geoquímica-Instituto de Geología Económica. Centro mixto UCM-CSIC, Complutense University of Madrid, 28040, Madrid, Spain aut Jeffries Teresa Department of Mineralogy, Natural History Museum, SW7 5BD, London, UK aut Mineralogy and Petrology Springer Vienna 101/3-4(2011-03-01), 151-167 0930-0708 101:3-4<151 2011 101 710 https://doi.org/10.1007/s00710-010-0142-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-010-0142-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Villaseca Carlos Departamento de Petrología y Geoquímica-Instituto de Geología Económica. Centro mixto UCM-CSIC, Complutense University of Madrid, 28040, Madrid, Spain aut NATIONALLICENCE 700 1- Orejana David Departamento de Petrología y Geoquímica-Instituto de Geología Económica. Centro mixto UCM-CSIC, Complutense University of Madrid, 28040, Madrid, Spain aut NATIONALLICENCE 700 1- Belousova Elena GEMOC, Department of Earth and Planetary Sciences, Macquarie University, 2109, Sydney, NSW, Australia aut NATIONALLICENCE 700 1- Armstrong Richard Research School of Earth Sciences, Australian National University, Canberra, Australia aut NATIONALLICENCE 700 1- Pérez-Soba Cecilia Departamento de Petrología y Geoquímica-Instituto de Geología Económica. Centro mixto UCM-CSIC, Complutense University of Madrid, 28040, Madrid, Spain aut NATIONALLICENCE 700 1- Jeffries Teresa Department of Mineralogy, Natural History Museum, SW7 5BD, London, UK aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer Vienna 101/3-4(2011-03-01), 151-167 0930-0708 101:3-4<151 2011 101 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer