摘要
西邑铅锌矿位于保山地块中北部,矿体定位受下石炭统香山组地层和矿区断裂控制,具有层控特征。硫同位素研究表明,西邑铅锌矿床中硫化物的δ34S值的区间为-2.4‰^+2.3‰,它们与地层中的重晶石的δ34S的值相差约15‰。分析表明,西邑铅锌矿床的硫化物的硫源主要来自地层中的重晶石,它们通过有机质的热分解反应还原为沉淀硫化物所必需的低价硫。矿石铅的铅同位素为206Pb/204Pb=18.547~19.044,207Pb/204Pb=15.608~15.661,208Pb/204Pb=38.541~38.880,显示铀铅富集、钍铅微弱亏损;矿石铅μ值介于于9.46~9.53之间,ω值的范围为35.48~36.79,显示铅源的物质成熟度高,具有上地壳或沉积物的特点。无论是矿床地质特征、还是同位素地球化学特征,均指示夹杂沉积硫酸盐的碳酸盐(含生物碎屑)沉积建造是最为理想的物源,矿床类型为沉积-热液型。
Xiyi Pb-Zn deposit is located in the north-center of the Baoshan Block,and ore bodies are stratabound controlled by the Xiangshan Formation of the Lower Carboniferous and faults in the orefield. The δ34S values of sulfides are- 2. 4‰ ～ ＋ 2. 3‰,and they differ by 15‰ from that of the barite in the strata. It is suggested that the sulfur sources of sulfides in the Xiyi Pb-Zn deposit are mainly derived from the barite in the strata,and they are the necessary low state sulfur of sulfide by the reduction of thermal decomposition reactions of organic materials. The Pb isotope composition of ore lead shows the enrichment of U-Pb and weak depletion of Th-Pb,with206 Pb /204 Pb = 18. 547 ～ 19. 044,207 Pb /204 Pb = 15. 608 ～ 15. 661,208 Pb /204 Pb = 38. 541 ～ 38. 880. The μ values of ore lead vary from 9. 46 to 9. 53,and the ω values of ore lead vary from 35. 48 to 36. 79,indicating that the ore-lead source was highly mature and was derived from the Xiangshan Formation. Therefore,the ideal material source is the carbonate（ including bioclastic）sedimentary formation mixed by sulfate,in terms of both its geologic characteristics and its isotope geochemical features.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第5期1327-1334,共8页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划项目(2015CB452604
2009CB421002)
长江学者和创新团队发展计划(IRT1083)
111计划项目(B07011)
中国地质调查局综合研究项目(1212010610104)联合资助
关键词
西邑铅锌矿床
硫同位素
铅同位素
成矿物质来源
保山地块
Xiyi Pb-Zn deposit Sulfur isotope Lead isotope Ore-forming material sources Baoshan Block
