Petrogenesis and Geochronology of the Dagang Muscovite‐Granite in the Central Qinzhou‐Hangzhou Metallogenic Belt, South China: Implications for Lithium‐Enrichment Mechanism of Granite‐Type Lithium Ore Deposit

ABSTRACT The central Qinzhou‐Hangzhou metallogenic belt in south China hosts large to supra‐large hard‐rock type lithium ore deposits. This contribution presents an integrated study of zircon U–Pb geochronology, whole‐rock and in situ Lu‐Hf isotopic geochemistry for the Dagang muscovite‐granite type Lithium ore deposit. LA‐ICP‐MS zircon U–Pb dating of five muscovite‐granitic samples yielded weighted average 206 Pb/ 238 U ages of 145 ± 3, 143 ± 1, 143 ± 1, 144 ± 3 and 144 ± 6 Ma, respectively, which are interpreted as the intrusion and mineralization ages of the granite. The Dagang granites have high SiO 2 , Na 2 O + K 2 O and Al 2 O 3 contents that are similar to those of strongly peraluminous granites. All the samples are depleted in Ba, Nb and Ti elements, but enriched Rb, Ta, Pb and U elements, as well as they have large negative ε Hf(t) values of −11 ± 1.3, −8.1 ± 0.6, −6.7 ± 1.5, −8.6 ± 0.9 and −10.3 ± 2.3, which are indicative of dominantly Mesoproterozoic continental crustal metasedimentary in origin. There is no obvious correlation between SiO 2 and Li, whereas SiO 2 /Al 2 O 3 show negative correlation with Li, in combination with positive correlations of LOI, Rb, Cs and Li, as well as consensual genetic views of high‐U zircons, it is proposed that lithium enrichment of the muscovite‐granite type lithium ore deposit occurred late stage of crystallisation differentiation of silicic magmatic system during Al‐rich mineral precipitation, and are superimposed of hydrothermal alteration.