Li-Hf isotope and geochronology constraints on Mesozoic granite type lithium deposit in southern Jiuling batholith in the eastern segment of Jiangnan orogeny, South China

• Compiled data reveals lithium mineralization peak ages of 153–138 Ma in south China. • Granite generated from Mesoproterozoic continental crust with mantle-derived source. • Granites have large δ 7 Li values with negative correlation with Nb/Ta and Zr/Hf ratios. Eastern segment of Jiangnan orogenic belt in South China outcrops Mesozoic super-large and large granite type lithium (Li) deposits that are essential for comprehensive investigation of mechanism and peak ages of lithium mineralization. This study presents combined research results from geochronology, whole-rock geochemistry, Lu-Hf and Li isotopic compositions of the Dagang muscovite granite Li deposit. Zircon analyses from two muscovite granite samples yielded interpreted crystallization ages of 147 ± 0.9 Ma and 145 ± 1.4 Ma, respectively. By integrating previously reported data, three mineralization stages (153–138 Ma, 132–125 Ma and 108–100 Ma) are proposed in the eastern segment of Jiangnan orogenic belt, among which the 153–138 Ma and 132–125 Ma stages are indicative of the peak ages of Li mineralization and polymetallic mineralization, respectively. The Dagang muscovite granite sample show that SiO 2 exhibits good linear relationships with Na 2 O, K 2 O, Al 2 O 3 , Fe 2 O 3 T, MgO and Mg#, with exception of Li. The Lu-Hf isotopic compositions have large negative ɛ Hf (t) values ranging from −3.05 to −9.41, suggesting that the Dagang muscovite granite was generated from Mesoproterozoic continental crust with minor contributions of mantle-derived sources. Additionally, the granite samples show positive δ 7 Li values ranging from +2.54‰ ± 0.17‰ to +5.68‰ ± 0.13‰, which are not only negatively correlated with Zr/Hf and Nb/Ta ratios, but also consistent with that of the upper mantle (+4 ± 2‰). It is thus interpreted that the Li concentration of the Dagang muscovite granite type Li deposit was controlled by hydrothermal alteration and mantle-derived materials.