%0 Journal Article
%A Orejana García, David
%A Villaseca González, Carlos
%A Valverde Vaquero, Pablo
%A Belousova, Elena
%A Armstrong, Richard A.
%T U–Pb geochronology and zircon composition of late VariscanS- and I-type granitoids from the Spanish Central Systembatholith
%D 2012
%@ 0016-7835
%U https://hdl.handle.net/20.500.14352/43918
%X The Spanish Central System (SCS) batholith,located in the Central Iberian Zone, is one of the largestmasses of granite in the European Variscan Belt. Thisbatholith is a composite unit of late- and post-kinematicgranitoids dominated by S- and I-type series granite, withsubordinate leucogranite and granodiorite. Zircon traceelement contents, from two representative S-type and threeI-type granitoids from the eastern portion of the SCSbatholith, indicate a heterogeneous composition due tomagma differentiation and co-crystallisation of other traceelement-rich accessory phases. In situ, U–Pb dating ofthese zircons by SHRIMP and LA-ICP-MS shows479–462-Ma inherited zircon ages in the I-type intrusions,indicating the involvement of an Ordovician metaigneousprotolith, while the S-type intrusions exclusively containCadomian and older zircon ages. The zircon crystallisationages show that these granites have been emplaced at ca.300 Ma with a time span between 303 ± 3 Ma and298 ± 3 Ma. Precise dating by CA-ID-TIMS reveals apulse at 305.7 ± 0.4 Ma and confirms the major pulse at300.7 ± 0.6 Ma. These ages match the Permo-Carboniferousage for granulite-facies metamorphism of the lowercrust under the SCS batholith and coincide with a widespreadgranitic event throughout the Southern Variscides.Ti-in zircon thermometry indicates temperatures between844 and 784C for both the S- and I-type granites, reinforcingthe hypothesis that these granites are derived fromdeep crustal sources.
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