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

Abstract

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 ∑REE + 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.