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沙坪沟钼矿床是大别山地区新近发现的、世界第二大的斑岩型钼矿床。本文在前期以及前人的工作基础上,通过详细的野外地质观察和系统的岩相学、矿相学以及探针测试分析工作,详细研究了沙坪沟钼矿床的蚀变与矿化特征。结果表明,沙坪沟钼矿床的围岩蚀变类型主要有钾硅酸盐化、青磐岩化和绢英岩化,绢英岩化又可细分为以石英为主和以绢云母为主。矿床中产出16种脉体类型,根据矿床的脉体类型划分了4个成矿阶段:(1)石英-钾长石阶段;(2)石英-硫化物阶段;(3)石英-绢云母阶段;(4)石英-萤石-石膏阶段。蚀变及矿化特征显示,沙坪沟钼矿床的钼矿化开始于石英-钾长石阶段晚期,结束于石英-绢云母阶段早期,石英-硫化物阶段是辉钼矿主要的形成阶段。沙坪沟钼矿床经历了多期次脉动式成矿流体的蚀变与矿化过程,在不同蚀变-矿化阶段中,成矿流体的物化条件和组分的变化是控制各阶段蚀变类型和脉体中矿物组合的主要因素。产于以伸展为主的板内环境的沙坪沟钼矿床与其他构造环境下的斑岩钼矿床在与成矿关系密切的岩石、蚀变分带等方面相似,但由于围岩性质的差异,矿体赋存位置及产状不同;而在矿物种类、矿化产出位置及产状、与矿化关系最为紧密的蚀变类型等方面存在差异。斑岩型钼矿床的构造背景可能控制了其岩浆的形成、演化以及含矿性,而岩浆岩最终定位的深度、围岩等条件也是控制蚀变和矿化特征的重要因素。
The Shapinggou molybdenum deposit is the newly discovered porphyry molybdenum deposit in the Dabie Mountain area, the second largest in the world. On the basis of previous work and predecessors’ work, this paper detailedly studied the alteration and mineralization characteristics of the Shapinggou molybdenum deposit through detailed field geological observation, systematic petrography, mineralogy and probe testing. The results show that the alteration types of molybdenum deposit in Shapinggou molybdenum deposit mainly include potassium silicate, metamorphic rocks and sericite rocks. The sericite rocks can be subdivided into quartz and sericite . There are 16 vein types in the ore deposit, and four ore-forming stages are divided according to the vein type of the deposit: (1) quartz-potassium feldspar stage; (2) quartz-sulfide stage; (3) quartz- Stage; (4) quartz - fluorite - gypsum stage. The alteration and mineralization characteristics show that the molybdenum mineralization of the Shapinggou molybdenum deposit began in the late stage of the quartz-potassium feldspar and ended in the early stage of the quartz-sericite. The quartz-sulphide stage was the major formation stage of molybdenite. The Shapinggou molybdenum deposit undergoes the alteration and mineralization process of multi-stage pulsatile ore-forming fluids. During different alteration-mineralization stages, the physicochemical conditions and compositional changes of the ore-forming fluid are controlled by the types of alteration And the main factors in the pulse combination of minerals. The Shapinggou molybdenum deposit produced in extensional slab environment is similar to the porphyry molybdenum deposit under other tectonic setting in terms of rock and alteration zonation closely related to metallogenesis. However, due to the difference in the properties of surrounding rock, There are differences in the locations and occurrences of ore bodies; however, there are differences in the types of minerals, the location and occurrence of mineralization, and the type of alteration most closely related to mineralization. The tectonic setting of the porphyry molybdenum deposit may control the formation, evolution and ore-bearing of the magma. The final location of the magmatic rocks and the surrounding rock are also important factors controlling the alteration and mineralization.