Batholith-stock scale exploration targeting based on multi-source geological and geophysical datasets in the Luanchuan Mo polymetallic district, China

摘要

The Luanchuan Mo polymetallic district, which hosts world-class porphyry-skarn-type Mo (W) deposits, is located in the Qinling orogenic belt of the North China Craton. The mining depth of the porphyry-skarn-type Mo (W) deposit in the Luanchuan district is close to 550 m, and most exploration drillholes extend to more than 1000 m. The upper crustal architecture is important for understanding the geological setting and metallogenic model for mineral potential targeting on a district scale. In this study, subsurface intrusions and structures were defined using multi-level gravity data processing (i.e., bi-dimensional empirical mode decomposition) and geophysical inversion (including gravity, magnetotellurics, and controlled-source audio-frequency magnetotellurics). The results of our integrated geological and geophysical studies suggest that the Late Jurassic granite stocks are controlled by NE NEE-and NW NWW-striking faults. The porphyry-skarn-type Mo (W) deposits are distributed around the ore-controlling Late Jurassic granite stocks, which are connected to the granite batholith at depth. The volume of this batholith is about 96.96 km(3). Based on geophysical interpretations and geochemical signatures of biotites from the granite stocks, the metallogenic potential of the granite stocks at Nannihu-Shangfanggou and Huangbeiling is considered to be greater than that of the granite stocks at Shibaogou Yuku.