Exhumation History and Exploration Potential of Gold Deposits in the NE Jiaodong Peninsula, North China: Evidence from Apatite and Zircon Fission Track Thermochronology

As the most important gold producer in China, the Northwest Jiaodong Peninsula is famous for its large gold deposits. In recent years, the discovery of gold mineralization has reached a depth of 4 000 m below the surface in this region. It has attracted significant interest from explorers about the prospecting potential at greater depths. Besides, the current deep drilling shows that the prospecting effect in the west portion is better than the region to the east. Does it imply that there is a difference in prospecting potential between the east and the west? This paper seeks to address the issue through fission track thermochronology on apatite and zircon to reveal the temperature-time evolution relationship of rock mass and to inverts their thermal evolution history. In addition, this study analyzes the transformation of ore deposits after mineralization, quantitatively calculates the uplift-erosion rate of rock mass, and summarizes the preservation law of ore deposits. Based on the thermal history simulation of the apatite fission track, our results show that the Guocheng gold belt has experienced three stages of thermal evolution: 108–74, 74–27, and 27–0 Ma. The uplift and cooling processes of the threestage tectonic uplift events are the results of multi-stage Pacific plate accretion. The calculated total denudation depth of the gold deposit in the Guocheng gold belt from Cretaceous to the present is about 3.4–5.3 km. The metallogenic depth of the ore body in the gold belt is 5.6–8.0 km, which indicates that the ore body in the Guocheng gold belt has suffered a significant degree of denudation. It is speculated that the location with less denudation in the southwest has greater prospecting potential. Our results quantitatively identify the uplift and denudation of the deposit after mineralization, which provides a new theoretical reference for regional mineralization, deep prospecting and exploration.