Combined cassiterite, scheelite, and apatite U-Pb dating of Sn-Cu(W) mineralization events in the Dayishan ore field, South China

The Dayishan ore field, a significant Sn-polymetallic production area in South China, hosts a variety of tin deposits, including the Lvzi'ao Cu (-Sn) deposit, Zhimashan Sn-Cu deposit, Baishaziling Sn deposit, and Maozaishan Sn (-W) deposit. However, the genetic relationships between the Sn-Cu-W deposits and the Dayishan granitic complexes remain unclear. Here, we present the U-Pb ages from zircon, cassiterite, apatite, and scheelite obtained from different granites and ore types within the Dayishan ore field. The Sn metallogenic age was determined through cassiterite U-Pb geochronology, yielding ages between 150 Ma and 153 Ma, while the Cu metallogenic age was identified through apatite U-Pb dating at 153.5 Ma. These ages are consistent with the zircon U-Pb age of Dayishan granitic complexes (152.37 Ma). In contrast, scheelite U-Pb geochronology provided an age of 133.58 Ma, characterizing the W metallogenic age. Geochemical variations in apatite from diverse deposits reveal systematic trends in F, Cl, and S contents and Cl/F ratios and FREE + Y concentration. The range of Y/Ho ratios in apatite suggests that the ore-forming material source of Sn and Cu deposits originated from a shared magmatic-hydrothermal fluids in Dayishan granitic complexes. Similarly, variations in cassiterite Zr/Hf and Nb/Ta ratios, along with a increasing oxygen fugacity, indicate a progressive decline in fluid temperature as the mineralization evolved. In contrast, the W deposit appear to a distinct magmatic-hydrothermal system associated with a deep concealed pluton formed during the Cretaceous. This suggests that the Sn-Cu mineralization in the Dayishan ore field was derived from a shared magmatic-hydrothermal system, which underwent significant during fluid evolution. Multidisciplinary evidence supports the existence of two stages of superimposed composite mineralization in Dayishan ore field, early Sn-Cu metallogenic stage was followed by a later W metallogenic stage, with the latter superimposed on the former, which together form multiple types of Sn-Cu(W) deposits in Dayishan granitic complexes.