太平洞-紫木凼金矿区同位素和稀土元素特征及成矿物质来源探讨  

Isotopes and REE Characteristic and Ore-Forming Materials Source of the Taipingdong-Zimudang Gold Deposit

作　　者：王泽鹏[1,2] 夏勇[1] 宋谢炎[1] 游彬[3,4] 郑新华[3,4] 汪小勇[3,4] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550002 [2]中国科学院研究生院,北京100049 [3]贵州省地矿局105地质大队,贵州贵阳550018 [4]贵州新恒基矿业公司,贵州黔西南552300

出　　处：《矿物学报》2012年第1期93-100,共8页Acta Mineralogica Sinica

基　　金：国家科技支撑计划课题(批准号:2006BAB01A13);贵州省地质矿产勘查开发局地质科研项目[黔地矿科(2009)11号];矿床地球化学国家重点实验室自主研究课题

摘　　要：太平洞-紫木凼金矿是黔西南地区灰家堡金矿田上的重要金矿床,位于灰家堡背斜的西段。雄黄、方解石分别作为金矿中重要的矿石矿物和脉石矿物,与金矿关系极为密切。通过对雄黄、方解石稳定同位素和方解石稀土元素地球化学研究,探讨金矿成矿物质来源问题。分析结果显示,雄黄δ34S值变化为+0.81‰～+3.03‰,极差为2.22‰,均值为1.6‰,数据变化较窄,均一化程度较高,具有接近幔源硫同位素特征,指示成矿物质可能主要来源于深部。方解石δ13CV-PDB为-8.473‰～0.866‰,主要集中在2个小的范围内,一是δ13CV-PDB在-4‰～-9‰之间,二是δ13CV-PDB在0‰附近,认为金矿床中碳可能为深部幔源碳和地层碳的混合,而氧主要来自地层。同时,方解石具有MREE富集及Eu正异常的特征,暗示成矿流体可能主要来源于深部且经历过还原的环境,形成富Eu2+的含矿热液,在运移过程中,由于温度、氧化还原条件等的改变,形成成矿晚期阶段特征的方解石脉。The Taipingdong-Zimudang gold deposit, which is hosted in the western Huijiabao anticline, is a major gold deposit in the Huijiabao gold ore-field in the southwest of Guizhou Province, China. Realgar and calcite, as the important ore mineral and gangue mineral respectively, are intimated to the Au-mineralization. Based on the study of stable isotope geochemistry of the realgar and calcite and REE of calcite, the ore source was discussed. The results show that δ^34S values of realgar range from 0. 81‰ to 3. 03‰ and close to the value of mantle with the range of 2. 22‰, mean value of 1.6‰, indistinctive variation and high homogenization, indicating that the ore-forming materials were derived mainly from deep place. The δ^13CV-PDBB values of calcite vary from -8. 473‰ to 0. 866‰, with two main distributions of -4‰ - -9‰ and around 0‰. The C-O isotopes reveal that the carbon in gold deposit may be a mixture of mantle carbon and the formation carbon, and oxygen mainly derives from the formation. Meanwhile, the enriched MREE and Eu positive anomaly of calcite imply that the ore-forming fluid derives mainly from deep place and has undergone deoxidization, forming Eu^2＋ enriched ore-bearing hydrothermal. During its migration, the calcite of the late stage precipitates as a result of change in temperature, redox condition, etc.

关 键 词：同位素 稀土元素 成矿物质来源 卡林型金矿 太平洞-紫木凼 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]