Time Limit of Gold Mineralization in Muping-Rushan Belt, Eastern Jiaodong Peninsula, China: Evidence from Muscovite Ar-Ar Dating

Controversy surrounds the genetic relationship between gold mineralization and magmatism, especially in deposits in granite. Jiaodong Peninsula is the leading gold province in China, and most deposits are in Mesozoic granites; moreover, debate on the genesis persists. In eastern Jiaodong, the Muping-Rushan gold belt produces mainly quartz-sulfide vein-type gold, and the Upper Jurassic Kunyushan granite and Late Lower Cretaceous Sanfoshan granite are the wall rock. Precise mineralization ages should be identified to determine whether gold is related to the intrusion. In this study, three gold deposits (Sanjia, Yinggezhuang, and Xipo) from two ore-controlling faults were considered. Muscovites from quartz-sulfide veins and beresite were selected for Argon-Argon dating. The results obtained were 116.51 +/- 0.47 Ma, 120.02 +/- 0.38 Ma, and 121.65 +/- 0.48 Ma for the three deposits, respectively. The mineralization lasted about 5 Ma in the Muping-Rushan gold belt. The test results showed that the mineralization was 16 Ma later than the intrusion time of Kunyushan granite and was earlier than that of Sanfoshan granite. Only the cooling age overlapped with the mineralization age. Previous studies have demonstrated that the ore fluid is of medium-low salinity and medium-low temperature. No typical high-low temperature mineral assemblage exists in the Muping-Rushan gold belt. Hence, gold deposits in Muping-Rushan gold belt could not be categorized as intrusion-related gold type.