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dc.contributor.authorWang, Qing
dc.contributor.authorZhu, Di-Cheng
dc.contributor.authorCawood, Peter Anthony
dc.contributor.authorZhao, Zhi-Dan
dc.contributor.authorLiu, Sheng-Ao
dc.contributor.authorChung, Sun-Lin
dc.contributor.authorZhang, Liang-Liang
dc.contributor.authorLiu, Dong
dc.contributor.authorZheng, Yuan-Chuan
dc.contributor.authorDai, Jin-Gen
dc.identifier.citationWang , Q , Zhu , D-C , Cawood , P A , Zhao , Z-D , Liu , S-A , Chung , S-L , Zhang , L-L , Liu , D , Zheng , Y-C & Dai , J-G 2015 , ' Eocene magmatic processes and crustal thickening in southern Tibet : insights from strongly fractionated ca. 43 Ma granites in the western Gangdese Batholith ' , Lithos , vol. In press .
dc.identifier.otherPURE: 226425453
dc.identifier.otherPURE UUID: fc2f9391-4d1a-4661-afda-cded0e77c11c
dc.identifier.otherRIS: urn:86DEF11603882A424A7BFDC7B07B159A
dc.identifier.otherScopus: 84947063138
dc.identifier.otherWOS: 000366770700010
dc.descriptionThis research was financially co-supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB03010301), the National Key Project for Basic Research of China (Project 2015CB452604), the Chinese National Natural Science Foundation (41225006, 41472061, and 40973026), the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources (China University of Geosciences). The first author thanks the China Scholarship Council (201306400021).en
dc.description.abstractThis study reports zircon U-Pb age and Hf isotope, whole-rock major and trace element, and Sr-Nd-Pb-Hf isotope data for the Dajia pluton, western Gangdese Batholith, in southern Tibet. These data indicate that the pluton consists of moderately (Group 1) and strongly (Group 2) fractionated granites that were emplaced synchronously at ca. 43 Ma. The Group 1 samples have SiO2 contents of 69−72 wt.% and vary in terms of the differentiation index (DI = 84−93). These rocks are depleted in Ba, Nb, Sr, P, and Ti, with moderate negative Eu anomalies, and display low heavy rare earth elements (HREEs) and Y abundances. The Group 2 samples are characterized by high SiO2 (75−78 wt.%) and DI (95−97); significantly negative Eu anomalies; marked concave-upward middle REE (Gd-Ho) patterns; and Ba, Sr, P, and Ti anomalies that are significantly more negative than those of the Group 1 samples. The Group 1 samples have whole-rock εNd(t) (-5.9 to -6.0), εHf(t) (-4.0 to -4.5), and zircon εHf(t) (-6.0 to + 5.8) values identical to those of the Group 2 samples [εNd(t) = -5.7 to -6.7, εHf(t) = -3.5 to -2.9, and zircon εHf(t) = -2.0 to + 4.2], as well as similar initial Pb isotopic compositions. These data indicate that the two groups were derived from a common source region with garnet as a residual mineral phase. The Group 1 samples were most likely derived from partial melting of garnet-bearing amphibolite (rather than eclogite) within the juvenile southern Lhasa crust and mixed with the enriched components from the subducting ancient Indian continental crust and/or the ancient central Lhasa basement. The Group 2 samples are interpreted as the products of extensive fractional crystallization (plagioclase, K-feldspar, biotite, apatite, allanite, titanite, monazite, and ilmenite) of the melts represented by the Group 1 samples. Low HREEs and Y abundances of the Dajia pluton, together with the presence of strongly fractionated granites (Group 2) identified for the first time in the Gangdese Batholith, indicate that the crust beneath the Dajia region had already been thickened by ca. 43 Ma. High whole-rock zircon saturation temperatures (815°C−869°C) of the Group 1 samples and the other ca. 43 Ma coeval magmatism documented both in the Gangdese Batholith and in the Tethyan Himalaya can be best interpreted as the final consequences of the magmatic responses to the Neo-Tethyan oceanic slab breakoff.
dc.rightsCopyright © 2015 Published by Elsevier B.V. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at:
dc.subjectStrongly fractionated granitesen
dc.subjectCrustal thickeningen
dc.subjectGangdese Batholithen
dc.subjectSouthern Tibeten
dc.subjectQE Geologyen
dc.titleEocene magmatic processes and crustal thickening in southern Tibet : insights from strongly fractionated ca. 43 Ma granites in the western Gangdese Batholithen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews.Earth and Environmental Sciencesen
dc.contributor.institutionUniversity of St Andrews.School of Geography and Geosciencesen
dc.contributor.institutionUniversity of St Andrews.Scottish Oceans Instituteen
dc.contributor.institutionUniversity of St Andrews.St Andrews Isotope Geochemistryen
dc.description.statusPeer revieweden

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