矿床地球化学国家重点实验室知识库

South China can be divided into four metallogenic belts: The Middle-Lower Yangtze Metallogenic Belt (MLYB), Qinzhou-Hangzhou Metallogenic Belt (QHMB), Nanling Metallogenic Belt (NLMB), and Wuyi Metallogenic Belt (WYMB). The major mineralization in the four metallogenic belts is granite-related Cu–Au–Mo and porphyrite Fe-apatite, porphyry Cu (Au), and epithermal Pb–Zn–Ag, hydrothermal Cu–Au–Pb–Zn–Ag, and granite-related skarn-type and quartz-veins W–Sn, respectively. Low-temperature thermochronology, including fission-track and U-Th/He dating, has been widely used to constrain tectonic thermal evolution and ore deposits preservation. Understanding fission-track annealing and He diffusion kinetics in accessory minerals, such as zircon and apatite, is essential for dating and applications. In this study, previous zircon fission-track (ZFT) and apatite fission-track (AFT) ages in South China were collected. The result shows that the ZFT ages are mainly concentrated at 140–90 Ma, and the AFT ages are mainly distributed at 70–40 Ma. The age distribution and inversion temperature–time paths reveal heterogeneous exhumation histories in South China. The MLYB experienced Late Cretaceous-Cenozoic extremely slow exhumation after rapid cooling in the Early Cretaceous. The northern QHMB (i.e. from southern Anhui province to the Hangzhou Bay) had a relatively faster rate of uplifting and denudation than the southern QHMB in the Cretaceous. Subsequently, the northern QHMB rapidly exhumed, while the continuously slow exhumation operated the southern QHMB in the Cenozoic. The southern NLMB had a more rapid cooling rate than the northern NLMB during the Cretaceous time, and the whole NLMB experienced rapid cooling in the Cenozoic, except that the southern Hunan province had the most rapid cooling rate. The WYMB possibly had experienced slow exhumation since the Late Cretaceous. The exhumation thickness of the four metallogenic belts since 90 Ma is approximately calculated as follows: the MLYB ≤ 3.5 km, the northern QHMB concentrated at 3.5–5.5 km, and the southern QHMB usually less than 3.5 km, the NLMB 4.5–6.5 km and the WYMB < 3.5 km. The exhumation thickness of the NLMB is corresponding to the occurrence of the world-class W deposits, which were emplaced into a deeper depth of 1.5–8 km. As such, we infer that the uplifting and denudation processes of the four metallogenic belts have also played an important role in dominated ore deposits.