Abstract
The North China Craton is one of China’s major gold-producing areas. Breakthroughs have been continually made in deep prospecting at depths of 500–2000 m in the Jiaodong Peninsula, and geophysical methods have played an important role. Given that the geophysical signals of deep-seated gold deposits are difficult to detect, due to their thick overburden layers, conventional geophysical methods are not suitable for deep prospecting. Therefore, this study upgrades the geological-geophysical prospecting model, which is based on the deep metallogenic model and geophysical method of large exploration depths. Based on the analysis of the metallogenic geological factors of the altered-rock-type gold deposits in the fracture zones of the Jiaodong Peninsula, this study proposes that the gold deposits are controlled by large-scale faults, generally occur near the contact interfaces between the Early Precambrian metamorphic rock series and Mesozoic granitoids, and exhibit a stepped metallogenic model. This model then becomes the prerequisite and basic condition for deep prospecting by geophysical methods. For this reason, the traditional geophysical model, which focuses on the exploration of shallow mineralization anomalies, is transformed into a comprehensive multi-parameter geological-geophysical qualitative prospecting model highlighting the exploration of ore-controlling structural planes. The model adopts various frequency domain methods (e.g., CSAMT, AMT, WFEM), reflection seismology, and other methods to detect the deep geological structure. The characteristics of parameters such as gravity and magnetism, resistivity, polarizability, and the seismic reflection spectrum are applied to identify the ore-controlling fault location and dip angle change, and to estimate the ore-bearing location according to the stepped metallogenic model. The prospecting demonstration of deep-seated gold deposits in the Shuiwangzhuang mining area indicates the effectiveness of the comprehensive model. The comprehensive deep prospecting model effectively solves the problem of deep prospecting of gold deposits controlled by faults, promotes the great breakthrough of deep prospecting in the Jiaodong Peninsula, and provides an important technology demonstration for deep prospecting throughout China.
Highlights
With its accumulated proven gold resources of greater than 5000 tonnes, the JiaodongPeninsula ranks as the world’s third largest gold concentration area
For the deep prospecting of the altered-rock-type gold deposits in the fracture zones of the Jiaodong Peninsula, the stepped ore-hosting model was taken as the theoretical basis, the physical characteristics of rocks and ores as the prerequisite, and the geophysical method combination and corresponding geophysical prospecting indicators was taken as the means
A qualitative geological-geophysical prospecting model used to identify deep-seated gold bodies according to multiple parameters was established, based on the experimental studies and application practices in the prospecting of typical deep-seated gold deposits (Figure 4)
Summary
With its accumulated proven gold resources of greater than 5000 tonnes, the JiaodongPeninsula ranks as the world’s third largest gold concentration area. Deep-seated super-large gold deposits have been successively detected under non- or weakly mineralized sections with a vertical thickness of 150–200 m below the shallow gold deposits such as Jiaojia and Matang. After this time, breakthroughs have been continually made in deep prospecting in the Jiaodong Peninsula. It has been revealed that many shallow gold deposits in the Sanshandao and Jiaojia areas, which had been previously considered to be independent, are interconnected into one deposit in the deep area With their total reserves exceeding 1000 tonnes, these two areas are the only kiloton class super-giant gold deposits in China [1]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
