Textures of auriferous quartz-sulfide veins and Ar-40/Ar-39 geochronology of the Rushan gold deposit: Implications for processes of ore-fluid infiltration in the eastern Jiaodong gold province, China

摘要

The Rushan gold deposit, located in the eastern part of the world-class Jiaodong gold province, contains the largest gold resource within a single fault-controlled quartz vein in China. Processes involved in auriferous quartz vein deposition are not clear, and the precise gold mineralization age remains controversial for this deposit. New Ar-40/Ar-39 dating data on sericite from ores and altered rocks suggest that the Rushan gold deposit formed between ca. 122 Ma and 117 Ma, which overlap or are slightly younger than those of gold deposits in northwestern Jiaodong province. The age differences between samples from different locations indicate that the quartz veins on the margin of the orebody may be younger than those in the center, suggesting a single and protracted gold mineralization event lasting for about 5 My. Differences between gold mineralization ages and emplacement/cooling ages of the ore-hosting Kunyushan granite imply that they are not genetically related and that the Kunyushan granite is unable to provide any thermal input to the mineralization system. This also applies to the Sanfoshan monzonite as it marginally postdated gold mineralization and lacks any spatial association with it.