caa a22 4500 445300353 CHVBK 20180317142555.0 cr unu---uuuuu 170323e20101001xx s 000 0 eng 10.1007/s11430-010-4058-0 doi (NATIONALLICENCE)springer-10.1007/s11430-010-4058-0 Zircon U-Pb geochronology, Hf isotopic composition and geological implications of the rhyodacite and rhyodacitic porphyry in the Xiangshan uranium ore field, Jiangxi Province, China [Elektronische Daten] [ShuiYuan Yang, ShaoYong Jiang, YaoHui Jiang, KuiDong Zhao, HongHai Fan] The Xiangshan uranium ore field is the largest volcanic rock hosted uranium deposit in China. The host rock is a volcanic intrusive complex, including rhyodacite, porphyroclastic lava and late stage sub-volcanic rocks. In this study, zircons from an early stage rhyodacite and a late stage rhyodacite porphyry were dated by SHRIMP and LA-ICP-MS U-Pb methods, and their Hf isotopic compositions were measured by LA-MC-ICP-MS. 206Pb/238U ages of 135.1±1.7 and 134.8±1.1 Ma were obtained for the rhyodacite and rhyodacitic porphyry, respectively. These accurate ages indicate that the Xiangshan volcanic-intrusive complex formed in the Early Cretaceous rather than in the Late Jurassic, as concluded in some previous studies. By the Early Cretaceous, the tectonic setting of the area has evolved into a back-arc extensional setting, possibly related to subduction of the paleo-Pacific plate. The close ages of the (early) eruptive rhyodacite and the (late) hypabyssal rhyodacitic porphyry shows that the Xiangshan volcanism was intensive and concentrated in a short time. Zircons from the rhyodacite show negative εHf(t) values of −5.7 to −8.5, with Hf depleted mantle model ages between 1550 and 1720 Ma, whereas zircons from the rhyodacitic porphyry yield εHf(t) values of −6.9 to −10.1 and Hf model ages between 1621 and 1823 Ma. These zircon Hf model ages are similar to the whole rock Nd model ages (1486 to 1911 Ma). Combined with other geochemical characteristics, the Xiangshan rhyodacite and rhyodacitic porphyry may have been derived from partial melting of the Paleo-Mesoproterozoic metamorphic rocks from the Xiangshan basement, without any significant addition of mantle-derived magma. Contribution of basement of this age is also supported by finding a Paleoproterozoic xenocrystic zircon core in the rhyodacite sample. Science China Press and Springer-Verlag Berlin Heidelberg, 2010 rhyodacite nationallicence rhyodacitic porphyry nationallicence U-Pb zircon age nationallicence Hf isotope nationallicence Xiangshan nationallicence Jiangxi Province nationallicence Yang ShuiYuan State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut Jiang ShaoYong State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut Jiang YaoHui State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut Zhao KuiDong State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut Fan HongHai Beijing Research Institute of Uranium Geology, 100029, Beijing, China aut Science China Earth Sciences SP Science China Press 53/10(2010-10-01), 1411-1426 1674-7313 53:10<1411 2010 53 11430 https://doi.org/10.1007/s11430-010-4058-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11430-010-4058-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yang ShuiYuan State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut NATIONALLICENCE 700 1- Jiang ShaoYong State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut NATIONALLICENCE 700 1- Jiang YaoHui State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut NATIONALLICENCE 700 1- Zhao KuiDong State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 210093, Nanjing, China aut NATIONALLICENCE 700 1- Fan HongHai Beijing Research Institute of Uranium Geology, 100029, Beijing, China aut NATIONALLICENCE 773 0- Science China Earth Sciences SP Science China Press 53/10(2010-10-01), 1411-1426 1674-7313 53:10<1411 2010 53 11430 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer