摘要
赤普铅锌矿床位于扬子地台西南缘川滇黔成矿区内,是川滇黔地区重要的铅锌矿床之一。通过野外和显微镜下观察。将成矿期形成的石英划分为Ⅰ、Ⅱ、Ⅲ三个阶段。本次选取了21件样品进行研究,对保存于石英、闪锌矿及硅化白云石中的原生包裹体进行的详细研究,赤普铅锌矿床中包裹体类型相对较为单一,以气液包裹体为主。Ⅰ、Ⅱ、Ⅲ阶段石英中流体包裹体均一温度和盐度范围分别为:230℃～270℃和2.74～19.68wt%(NaCl),150℃～200℃和3.71～16.99wt%(NaCl)和180℃～220℃和0.70～16.15wt%(NaCl)三个区间。主成矿阶段的闪锌矿流体包裹体的均一温度和盐度范围为127℃～210℃和4.34%～22.17%(NaCl)。该矿床成矿流体均一温度和盐度范围主要在130℃～200℃和8.5%～17.0%(NaCl)之间,属于低温、中等盐度铅锌矿床。成矿流体为H_2O-NaCl-CaCl_2体系;成矿过程中成矿流体始终处于相对还原环境。成矿物质来源于上地壳,成矿流体主要来自围岩地层;成矿机制可能为含金属和含还原硫流体混合成矿。该矿床应归属于密西西比型铅锌矿床。
Located on the southwestern margin of the Yangtze craton, the Chipu Pb-Zn deposit is one of the major Pb-Zn deposits in the Sichuan-Yunnan-Guizhou region. Based on the field and microscopic observations, three stages of quartz formed in the mineralization phase have been distinguished. In this study 21 samples were used and the primary inclusions preserved in quartz, sphalerite and silicified dolomite were studied intensively. The inclusion types in the deposit are relatively simple, dominated by vapor-liquid inclusions. The ranges of homogenization temperatures and salinities of the fluid inclusions for each stage are: stage 1, 230 to 270 degrees C and 2. 74 to 19. 68 wt% NaCl equiv.; stage 11, 150 to 200 degrees C and 3. 71 to 16. 99 wt% NaCl equiv.; stage 111, 180 to 220 degrees C and 0. 70 to 16. 15 wt% NaCl equiv. The homogenization temperatures and salinities of the fluid inclusions for sphalerite in the main mineralization phase range from 127 to 210 degrees C and from 4. 34 to 22. 17 wt% NaCl equiv. respectively. The homogenization temperatures and salinities of ore-forming fluids of the deposit are 130 to 200 degrees C and 8. 5-17. 0 wt% NaCl equiv. respectively. The deposit belongs to a low-temperature, moderate-salinity Pb-Zn deposit. Based on the geological and fluid inclusions characteristics of the deposit, the authors think that the ore-forming fluids belong to the H2O-NaCl-CaCl, system and always remained in a reducing environment. The ore-forming materials were derived from the upper crust and the ore-forming fluids mainly came from the host carbonate rocks. Sulfide precipitation was probably caused by mixing of metal-hearing and reduced sulfur-bearing fluids at the site of mineralization. This deposit should belong to MVT deposits.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第10期2541-2552,共12页
Acta Petrologica Sinica
基金
地质大调查项目"我国主要金属矿床模型研究"(1212010634001)
国家自然科学基金项目"滇东北峨眉山玄武岩中有机质对铜富集成矿的作用"(40572060)资助。
关键词
均一温度
流体包裹体
成矿机制
铅锌矿床
赤普
homogenization temperature
fluid inclusion
mechanism of mineralization
Pb-Zn deposit
Chipu
