Metallogeny and exploration indicators of Sn and Ag deposits in the Southern Great Xing'an Range, China: Application of knowledge-driven CoDA based on geology and geochemistry

Abstract

There have been recent breakthroughs in exploration for tin (Sn) and silver (Ag) mineral resources in the Southern Great Xing'an Range, making this region a world-class Sn and Ag metallogenic area. However, thick surface coverage and hidden deposits make exploration difficult, and conventional geological and geochemical prospecting methods have severely limited efficacy. In order to further extract geological and geochemical information on the basis of the existing research, to serve the regional mineral exploration, the knowledge-driven CoDA method is used to identify geochemical associations for inferring matallogenic information. Meanwhile, the fractal C-A model is used to determine geochemical anomalies, the catchment basin geochemical method is used to delineate anomaly boundary. Especially, the data-driven CoDA method is employed for comparison analysis with the knowledge-driven one. As a result, seven groups of compositional balances are proposed and verified, and geological bodies closely related to Sn and Ag mineralization are identified. These occurred in Dashizhai Formation strata, being calcareous rocks and granites, especially A-type granite, which is most closely related to mineralization. Meanwhile, Sn and Ag mineralization areas were identified and found to be consistent with known deposits. Finally, this paper proposes a novel model of regional porphyry Sn–Cu metallogenic systems and delineates exploration targets for Ag–Zn–Pb–Cu deposits and Sn–polymetallic deposits based on the analysis of catchment basins.