A Discussion on the Origin of Witherite Deposits in Large-Scale Barium Metallogenic Belt, Southern Qinling Mountains, China: Evidence from Individual Fluid Inclusion

• 责任者：Liu Jiajun (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Wu Shenghua
• 刊名：Earth Science Frontiers
• 出版年：2010
• 卷期：17(2)
• 关键词：毒重石矿床 ; witherite deposit ; 流体包裹体 ; fluid inclusions ; 秦岭 ; Qinling Mountains
• 页码：p.222-238
• 图表：7 illus., 3 tables, 57 refs.
• 分类号：1002
• issnNo：ISSN1005-2321
• isbnNo：CN11-3370/P

The barite deposits in which Ba presents as BaSO₄ are widespread in the world, whereas the witherite deposits in the presence of BaCO₃ are rarely reported. This paper focuses on the fluid inclusion features of witherite, barytocalcite, barite, and quartz in the barium metallogenic belt. The results indicate that the homogenization temperature of fluid inclusions of each mineral ranges from 90 to 310 ℃, mainly concentrating at the range of 120～220 ℃.  The fluid inclusions of the barite mainly are of NaCl- H₂O type, whereas the fluid inclusions of witherite are rich in aqueous solution with complicated components like N₂-CO₂-H₂S-CH₄ etc., which shows that there is a large difference between the metallogenic environments of witherite and barite. Based on these evidences, the authors suggest that the thermochemical sulfate reduction (TSR) of the solution was the main formation mechanism of witherite deposits.