The large-scale Maoping W–Sn deposit in the Gannan metallogenic belt of the eastern Nanling Range, South China, spatially associated with the Maoping granite pluton, hosts total ore reserves of 103,000 t WO₃ and 50,000 t Sn. Two different types of mineralization developed in this deposit: Upper quartz vein-type mineralization, mostly within the Cambrian metamorphosed sandstone and slate, and underneath greisen-type mineralization within the Maoping granite. Cassiterites from both types of mineralization coexist with wolframite. Here we report for the first time in situ U–Pb data on cassiterite and zircon of the Maoping deposit obtained by LA-ICP-MS. Cassiterite from quartz vein and greisen yielded weighted average ²⁰⁶Pb/²³⁸U ages of 156.8 ± 1.5 Ma and 156.9 ± 1.4 Ma, respectively, which indicates that the two types of mineralization formed roughly at the same time. In addition, the two mineralization ages are consistent with the emplacement age of the Maoping granite (159.0 ± 1.5 Ma) within error, suggesting a close temporal and genetic link between W–Sn mineralization and granitic magmatism. The two types of mineralization formed at the same magmatic-hydrothermal event. Cassiterite from both types of mineralization shows high Fe, Ta, and Zr contents with a low Zr/Hf ratio, suggesting that the ore-forming fluid should be derived from the highly differentiated Maoping granite pluton. Cassiterite in greisen has higher contents of Nb and Ta but a lower concentration of Ti compared with that in quartz vein, indicating that the formation temperature of greisen-type mineralization is little higher than that of quartz-vein-type mineralization.

Wolframite-quartz vein-type tungsten deposits constitute the world’s major tungsten resources and are integral to tungsten production. A major share of this mineralization product is found in Southeast China, with other significant resources in the Central Andean belt, the East Australian belt, the Karagwe-Ankole belt and the European Variscan belt. In the past few decades, extensive studies on wolframite-quartz vein-type tungsten deposits have been conducted, but many key questions concerning their ore-forming fluid and metallogenic mechanism remain unclear. Additionally, a summary work on the global distribution and fluid characteristics of these wolframite-quartz vein-type tungsten deposits is still lacking. In this contribution, recent progress regarding several major issues related to the fluid processes involved in the forming of these veins are overviewed, and challenges in terms of future research are proposed. These issues include the nature of ore-forming fluids, their sources, and their transportation and wolframite deposition mechanisms. In particular, the affinity between veins and the exposed granitic intrusion from the Zhangtiantang-Xihuashan ore district, where an as-yet undiscovered deep intrusion, rather than the exposed granitic intrusion, was probably responsible for the formation of the wolframite-quartz veins, is reevaluated. This study also reviews the existing fluid and melt inclusion data from several tungsten deposits to address whether the mineralization potential of the magmatic-hydrothermal systems was directly correlated with the metal contents in the granitic melts and the exsolving fluids.

The Chuankou tungsten ore field is situated in the central area of the Xuefeng Uplift Belt in South China. The deposit is characterized by two types of tungsten mineralization: quartz-scheelite veins in both the Neoproterozoic Banxi Group and Devonian Yanglin’ao Formation and quartz-wolframite (scheelite) veins in the Chuankou granite. The host rocks of the Chuankou tungsten Deposit of South China are similar to the stratigraphic sequence of Au-Sb-W deposits in the Xuefeng Uplift Belt. It is thus an appropriate location for the study of scheelite mineralization in the belt, especially the relative contributions of surrounding rocks, magma and hydrothermal fluids. Optical Microscope-Cathodoluminescene (OM-CL) and Laser Ablation Inductively Coupled Mass Spectrometers (LA ICPMS) were used to examine scheelite textures and trace element concentrations in the Chuankou deposits. Scheelite in quartz-scheelite veins was formed over three generations. In situ LA-ICPMS trace elemental analyses of scheelite I show light rare earth element (LREE)-rich REE patterns and negative Eu anomalies, suggesting a relatively close fluid system. Significantly positive Eu anomalies of scheelite II and III indicate variable degrees of addition of meteoric water during scheelite precipitation. Therefore, ore-forming fluids of the Chuankou deposit were dominantly magma-derived, with different contributions of recycled meteoric water in the surrounding strata.