Research and discussion on the metallogenic epochs of the Xiashan Pb-Zn deposit in Zhenghe County, Fujian Province

The Xiashan Pb-Zn deposit is a large-sized Pb-Zn deposit discovered in Fujian Province in the 1950s. Although most researchers have classified this deposit as a sedimentary-reworked Pb-Zn deposit, some geologists still believe that it is a skarn type deposit formed by the intrusion of the Tongpenan pluton (syenite granite) in Yanshanian period. Based on geological survey, the authors hold that the distribution and morphology of orebodies are closely related to granite porphyry. Ore-related granite porphyry samples from the Xiashan Pb-Zn deposit were dated by zircon La-ICP-MS U-Pb chronology, which yielded an age of 173±1.7 Ma. This result confirms that the Xiashan Pb-Zn deposit involved a skarn mineralization process of Early Yanshanian period which was earlier than the intrusion of the Tongpenan pluton (155-150 Ma). In addition, the age of 173±1.7 Ma is consistent with the metallogenic epoch of Cu, Ag, Pb and Zn polymetallic deposits in northeastern Jiangxi Province, suggesting that the Wuyi Mountain metallogenic belt in Fujian Province had a positive response to the first large metallogeny of the Early Yanshanian period in southern China, and has the potential in the search for Cu, Ag, Pb and Zn polymetallic deposits. According to the results obtained by the authors and previous studies, two important metallogenic periods (173 Ma and 90-125 Ma) of Yanshanian period can be recognized in the Wuyi Mountain metallogenic belt, especially in the north region. These results are of great significance for discovering and studying the concealed and superimposed deposits in the Wuyi Mountain metallogenic belt.