Structural ore−controlling mechanism of the Qingshan lead−zinc deposit in northwestern Guizhou, China and its implications for deep prospecting

This paper is the result of mineral exploration engineering.

Objective The Qingshan medium−size Pb−Zn deposit is located in the middle of the Weining−Shuicheng metallogenic sub−belt in the southwest margin of the Yangzi Block. The ore−body of the Qingshan deposit is strict controlled by structure and the resource potential is huge.

Methods Based on the theory and method of orefield geomechanics, this research has revealed the mechanism of structural ore control by the fine survey of large−scale structural profile, the identification of mechanical properties of typical ore−controlling structures in different directions and the screening of structures in different periods and orders, combined with the characteristics of regional tectonic stress field.

Results The results show that the principal compressive stress direction of the mining area since the Indosinian had changed from NE−SW−trending to NW−SE−trending to NE−SW−trending to near EW−trending, sequentially forming tectonic systems of the early NW tectonic belt, the NE tectonic belt, the late NW tectonic belt and the SN tectonic belt in turn. By the analysis of ore−controlling structure and the discussion of its relationship with mineralization, the metallogenic structural system of the north−east tectonic belt has been determined, and the hierarchical ore−controlling regularity of structure is revealed, it is, the northwest−trending Weining−Shuicheng fault and Weining−Shuicheng anticline are the first−grade ore−controlling structures, which control the distribution of the Weining−Shuicheng metallogenic sub−belt or orefield; The NW−trending faults (F₁ and F₂) derived from the Weining−Shuicheng fault, control the distribution of the deposit or orebody group, and are the second−grade ore−controlling structures in the mining area; The interlayer fracture zones between F₁ and F₂ faults directly control the feature and attitude of orebodies, which is the third−grade ore−controlling structure in the mining area; The joint fissures on the sides of orebodies control the ore−veins, which is the fourth−grade ore−controlling structure.

Conclusions The regularities of structural classification control are obvious for the Qingshan Pb−Zn deposit, which is mainly controlled by the ore−controlling structures of four grades, and has formed the four types of mineralization styles.