热液矿床水相变控矿理论初探  

The theory of water phase transitions controlling hydrothermal mineralization

作　　者：胡宝群[1] 吕古贤[2] 孙占学[1] 李满根[1] 廖玉婷[1] 郭国林[1] 白丽红[1] 

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室/核资源与环境教育部重点实验室,江西南昌330013 [2]中国地质科学院地质力学研究所,北京100081

出　　处：《地质通报》2011年第4期565-572,共8页Geological Bulletin of China

基　　金：国家自然科学基金项目<热液铀成矿中水的物理化学行为及与地质作用耦合关系的研究>(批准号:40862005);<砂岩铀矿地浸采铀过程中的流体-岩石相互作用研究>(批准号:40872165);江西省自然科学基金项目<铀矿山废渣中的酸性废水形成及其控制的实验研究>(编号:2008GZH0053);国防科工委放射性地质与勘探技术国防重点学科实验室基金项目<相山火山岩型铀矿床成矿机理研究>(编号:2010RGET01);江西省教育厅科技项目<铀矿山酸性废水形成机制及抑制剂选择研究>(编号:2007-230)

摘　　要：在综合水物理化学性质、热液矿床、溶解度实验研究等资料的基础上,曾提出热液矿床水相变控矿理论框架。在此进一步完善该理论:①当水发生相变时可引起热容、水中矿质溶解度、压缩系数、膨胀系数等物理化学性质突变,特别是在临界点处二级相变时还出现"临界奇异性"、部分参数趋于无穷大,与水在非相变区物理化学性质的小幅度渐变区别明显,必将影响成矿物质的活化、迁移和沉淀。而水是否相变及其相变种类取决于构造、岩浆活动、地温梯度等,按岩石圈正常地温线则直接取决于断裂、皱褶、韧性剪切等降压条件是否存在,由此可以通过热液成矿作用研究来探讨区域大地构造演化过程。②该理论有3个关键:水在相变区和非相变区的物理化学性质的明显差异,使含水系统中成矿物质带入、带出成为可能;出现与临近相变温压一致的地质环境,使成矿物质大量活化进入热液;后期局部降压使水相变而释放出成矿物质。总体而言,热液矿床水相变控矿理论研究岩石圈温度和压力变化范围内含水体系的物理化学性质变化及相关的地质响应,属构造物理化学的内容。Based on the researches of water physicochemical properties,hydrothermal deposits and solubility experiments,the sketch of the ore-controlling theory of water phase transition in hydrothermal deposit was given ago.Now the following shows the latest version of this theory：（1） the water phase transition may cause some mutations of physicochemical properties,such as the heat capacity,mineral solubility in water,compressibility coefficient and expansion coefficient.Especially the second-order phase transition at the critical point induces the critical singularity which some physicochemical parameters tend to be the infinity.The significant changes of physicochemical properties at water phase transitions are obviously different from small-amplitude and gradual change at the district without phase transition.The differences will significantly influence the dissolution,migration and depositing of ore-forming materials in the lithosphere.The water phase transition and its type depend on the structure,magmatic activity and the geothermal gradient.According to normal geothermal curves in the lithosphere,the pressure reducing from fracture or fold or ductile shear is essential to induce the water phase transition.Therefore,the study of hydrothermal mineralization can also give some valuable information on the regional tectonic evolution.（2） There are 3 key steps in this theory.Firstly,the significant differences of water physicochemical properties between phase transition area and no-phase transition area in phase diagram,can give the probability to carry the ore-forming materials into or out of water-bearing system in the lithosphere.Secondly,the geological environment with the temperature and pressure near to water phase transition is essential for the thermal geo-fluid to dissolve a large amount of ore-forming materials.Lastly,it is also necessary that reducing pressure in some parts of the lithosphere induces the phase transition of water,in which the ore-forming materials in thermal geo-fluid can be released

关 键 词：水 相变 物理化学性质 突变 渐变 临界奇异性 热液成矿作用 

分 类 号：P611.13[天文地球—矿床学]