The Metallogenic Mechanism of Skarn Sn-Polymetallic Deposits in the Southern Great Khingan Range, China: Constraints on the Geological and Geochemical Characteristics of Damogutu Sn–Fe and Dashishan Sn–Pb–Zn Deposits

Abstract

Skarn Sn-polymetallic deposits, located in the southern Great Khingan Range, can be divided into Sn−Fe and Sn−Pb−Zn deposits. By systematically studying the geochemical characteristics of source granitoid and deposits, the ore-forming mechanisms were established, and the differences in ore-forming processes between Sn−Fe and Sn−Pb−Zn deposits are discussed. The main findings are as follows: (1) these two deposits were formed in the Late-Yanshanian period; (2) the source granitoid evolved at an early stage in a reducing environment, while the oxygen fugacity increased at a late stage through the influence of a deep-seated fault; (3) fine-grained syenogranite from Dashishan showed a higher degree of evolution than the syenogranite from Damogutu; (4) the Damogutu Sn−Fe and Dashishan Sn−Pb−Zn deposits shared a source of ore-forming fluid, and Fe, Sn, Pb, and Zn all derived from Late-Yanshanian granitoids; and (5) the ore-forming fluid experienced a continuous evolution process from the magmatic to hydrothermal stage, and the magmatic−hydrothermal transitional fluid played a very important role in skarnization and mineralization.

Keywords

• Damogutu Sn–Fe deposit
• Dashishan Sn–Pb–Zn deposit
• source granitoid
• ore-forming fluids
• skarn deposit