| 板溪锑矿两类石英脉成因及其对找矿的指示意义 |
| |
| 引用本文： | 林智炜,吴堑虹,李欢,奚小双,孔华,唐宇蔷,刘飚.板溪锑矿两类石英脉成因及其对找矿的指示意义[J].地球科学,2020,45(5):1503-1516. |
| |
| 作者姓名： | 林智炜 吴堑虹 李欢 奚小双 孔华 唐宇蔷 刘飚 |
| |
| 作者单位： | 1.中南大学地球科学与信息物理学院, 湖南长沙 410083 |
| |
| 基金项目： | 中南大学研究生自主探索创新项目2018zzts068 |
| |
| 摘 要： | 板溪矿区内广泛发育无矿石英脉,其与含矿石英脉空间关系密切,但人们对两者是否具有成因联系并不清楚.围绕该问题作者开展了二者形成时代、成分组成及物质来源等方面的对比研究,结果发现含矿石英脉旁侧总是发育与其平行的无矿石英脉,二者无穿插关系,但存在连接二者的石英脉,结合区域地质资料认为无矿石英脉形成于燕山期,与含矿石英脉形成时代一致;无矿石英脉局部含微量辉锑矿±黄铁矿,脉体发育绢云母化、硅化等围岩蚀变,与含矿石英脉一致;无矿石英脉流体包裹体均一温度(143~266℃)和盐度(1.7%~8.5%NaCl eqv.)较含矿石英脉的均一温度(185~332℃)和盐度(3.3%~7.7%NaCl eqv.)略低,但二者均为中低温、低盐度的流体体系;激光拉曼分析显示两者流体气相组分均为H2O±CO2±CH4±N2,LA-ICP-MS测试结果显示无矿石英脉与含矿石英脉均含Sb、Fe、As等元素;无矿石英脉包裹体的δD值(-74.4‰^-69.7‰)、δ18OH2O值(2.6‰~3.4‰)、硫化物δ34S值(3.04‰~4.87‰)与含矿石英脉包裹体的δD值(-140‰^-107‰)、δ18OH2O值(5.9‰~8.4‰)、硫化物δ34S值(3.46‰~6.12‰)相似性较高,指示二者具有相同的物质来源.两类石英脉应属同一成矿热液系统,其差异是成矿流体混合的结果,因此其他热液矿床,特别是矿田范围内的无矿石英脉可能对矿脉具有指示作用,应引起重视.
|
| 关 键 词： | 无矿石英脉 热液矿床 流体包裹体 流体组分 板溪锑矿 矿床地质 |
| 收稿时间： | 2019-08-30 |
The Genesis of Two Types of Quartz Veins in Banxi Antimony Deposit and Their Prospecting Significance |
| |
| Lin Zhiwei,Wu Qianhong,Li Huan,Xi Xiaoshuang,Kong Hua,Tang Yuqiang,Liu Biao.The Genesis of Two Types of Quartz Veins in Banxi Antimony Deposit and Their Prospecting Significance[J].Earth Science-Journal of China University of Geosciences,2020,45(5):1503-1516. |
| |
| Authors: | Lin Zhiwei Wu Qianhong Li Huan Xi Xiaoshuang Kong Hua Tang Yuqiang Liu Biao |
| |
| Affiliation: | (School of Geosciences and Info-Physicsy Central South University,Changsha 410083,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha 410083,China;Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration,Changsha 410083,China) |
| |
| Abstract: | The Banxi antimony deposit is located in the Central Hunan Sb belt,which is a quartz vein type deposit that has been mined for more than 100 years. Like many hydrothermal deposits,the Banxi deposit has many ore-free quartz veins,which are parallel with the ore-bearing quartz veins at a relatively fixed distance. However,the genetic connection between ore-free and ore-bearing veins is not clear. Based on the comparison of the forming age and fluid components of the two types of quartz veins,the genetic relationship between the two types of quartz veins and the possible geological significance of the ore-free quartz veins are discussed. Field observations,examination of fluid inclusions and hydrogen,oxygen,and sulfur isotope analyses reveal that the two types of quartz veins has no interpenetrating relationship,but the ore-free and ore-bearing veins are physically connected. Integrated with regional geological data,it is concluded that the ore-free vein was formed in Yanshanian period,which was consistent with the ore-bearing vein. The ore-free quartz veins contain a small amount of stibnite and pyrite. Sericitization,silicification and other types of wall rock alteration are both developed on the side of the two types of veins. Micro thermometric analyses of fluid inclusion in ore-free quartz veins yield homogenization temperature ranges of 143-266 ℃ and salinities of 1.7%-8.5% NaCl eqv.. While ore-bearing quartz veins inclusions have ranges of 185-332 ℃ with salinities of 3.3%-7.7% NaCl eqv.,showing that both types of veins formed in medium-low temperature and low salinity fluid systems. Laser Raman analyses of a fluid inclusion from both types of veins show that the gas phase components of both fluids are H2O±CO2±CH4±N2. LA-ICP-MS test results confirm that both types of veins contain the same elements (Sb,Fe,As,etc.),and that their fluid components are very similar. The values of δD and δ18OH2O of the ore-free quartz veins vary from -69.7‰ to -74.4‰,and 2.6‰ to 3.4‰,while the values in ore-bearing quartz vein vary from -140‰ to -107‰,and 5.9‰ to 8.4‰. The values of δ34S of sulfide are 3.04‰-4.87‰ (ore-free quartz vein) and 3.46‰-6.12‰ (ore-bearing quartz vein). Previous geologic work and field observations during this study indicate that quartz porphyry veins in the mining area developed without significant magmatic activity. This suggests that the original fluid for both types of veins was metamorphic water,and that the nature of quartz veins changed with time,regional cooling and different levels of meteoric water participation. In both types of veins,sulfur found in sulfides was derived from the host formation. The spatial relationship between the two types of quartz veins and their similar components and sources of ore-forming materials indicate that the two types of quartz veins are close to the same age of formation and belong to the same metallogenic hydrothermal system. The slight difference in geological and geochemical characteristics between the two types of quartz veins is the result of the continuous evolution and differentiation of ore-forming fluids. The study of the genetic relationship between the two types of quartz veins provides an example for the study of the ore-forming fluid mixing of this type of deposit. The distribution characteristics of the two types of quartz veins parallel at a relatively fixed distance not only provide a new mark for prospecting for banxi antimony deposit,but also enlighten us to pay attention to the possible indicating role of ore-free quartz veins in some deposits of this type or in the new exploration area for the ore-bearing quartz veins. |
| |
| Keywords: | ore-free quartz vein hydrothermal deposits fluid inclusions fluid components Banxi antimony deposit deposit geology |
| 本文献已被 CNKI 维普 等数据库收录！ |
| 点击此处可从《地球科学》浏览原始摘要信息 |
|
点击此处可从《地球科学》下载全文 |
|
