Petrogenesis of the Late Jurassic peraluminous biotite granites and muscovite-bearing granites in SE China: geochronological, elemental and Sr–Nd–O–Hf isotopic constraints

• Published in: Contributions to mineralogy and petrology 2017-12, Vol.172 (11-12), p.1-27, Article 101
• Main Authors: Jiang, Yao-Hui, Zhu, Shu-Qi
• Format: Article
• Language: English
• Subjects: Barium; Bearing; Biological evolution; Biotite; Chronology; Crystallization; Earth and Environmental Science; Earth Sciences; Fluids; Fractional crystallization; Fractionation; Geochemistry; Geochronology; Geology; Granite; Igneous rocks; Isotopes; Jurassic; Lava; Magma; Melts (crystal growth); Mesozoic; Mineral Resources; Mineralization; Mineralogy; Muscovite; Neodymium; Niobium; Original Paper; Petrogenesis; Petrology; Plagioclase; Plutons; Precambrian; Ratios; Rocks; Rocks, Sedimentary; Saturation; Schist; Schists; Silicon dioxide; Strontium; Strontium 87; Strontium isotopes; Uranium; Zircon
• ISSN: 0010-7999; 1432-0967
• DOI: 10.1007/s00410-017-1422-5

Biotite granites and muscovite-bearing granites are dominant rock types of the widespread granites in SE China. However, their petrogenesis has been enigmatic. A combined study of zircon U–Pb dating and Lu–Hf isotopes, whole-rock element geochemistry and Sr–Nd–O isotopes was performed for three late Mesozoic granitic plutons (Xinfengjie, Jiangbei and Dabu) in central Jiangxi province, SE China. All the plutons are composed of biotite granites and muscovite-bearing granites that have been poorly investigated previously. The new data not only allow us to assess their sources and magma evolution processes, but also helps us to better understand the genetic link to the large-scale polymetallic mineralization in SE China. LA-ICP-MS zircon U–Pb dating shows that three plutons were emplaced in the Late Jurassic (159–148 Ma) and that the muscovite-bearing granites are almost contemporaneous with the biotite granites. The biotite granites have SiO 2 contents of 70.3–74.4 wt% and are weakly to strongly peraluminous with ASI from 1.00 to 1.26, and show a general decrease in ASI with increasing SiO 2 . They have relatively high zircon saturation temperatures ( T Zr  = 707–817 °C, most > 745 °C) and show a general decrease in T Zr with increasing SiO 2 . They have high initial 87 Sr/ 86 Sr ratios (0.7136 to 0.7166) and high δ 18 O values (9.1–12.8‰, most > 9.5‰) and clearly negative ε Nd (T) (− 9.5 to − 11.8) and ε Hf (T) (in situ zircon) (− 13.1 to − 13.5). The muscovite-bearing granites have high SiO 2 contents (74.7–78.2 wt%). They are also weakly to strongly peraluminous with ASI of 1.04–1.18 but show a general increase in ASI with increasing SiO 2 . They have relatively low T Zr (671–764 °C, most