【作者】 方福康；

【导师】 杜杨松；

【作者基本信息】 中国地质大学(北京) ， 矿产普查与勘探， 2012， 硕士

【摘要】 城门山铜矿床位于长江中下游成矿带九瑞矿集区的南东端，由“斑岩型+矽卡岩型+块状硫化物型”三种矿体类型组成，在长江中下游成矿带具有典型意义。本文选择与石英斑岩体密切相关的斑岩型铜钼矿作为研究对象，通过流体包裹体对城门山斑岩铜钼矿的成矿流体进行了详细的研究，取得了以下主要认识和成果。1、城门山斑岩铜钼矿经历了岩浆期和热液期的成矿过程。岩浆期流体包裹体均一温度集中于220-540℃，盐度集中在28-54%NaCleq，流体密度集中在0.9-1.2g/cm³，压力集中在3-60MPa；而热液期包裹体的均一温度集中在220-460℃，盐度集中在30-45%NaCleq，密度集中于1.0-1.2g/cm³，压力集中在3-55MPa。结合同位素资料分析，认为岩浆期成矿流体来自岩浆，热液期成矿流体主要来源于岩浆，但受到少量大气降水的混合。2、城门山斑岩铜钼矿两期成矿流体的气相成分都以H2O为主，液相成分中阴离子为Cl^-、SO₄^2-、F^-等，阳离子为K⁺、Na⁺、Ca²⁺、Mg²⁺等，但以Na⁺、K⁺、Cl^-为主。另外在多相包裹体中普遍存在黄铜矿，表明成矿流体中富含Cu²⁺，Fe²⁺等金属离子。因此，推断城门山斑岩铜钼矿的成矿流体为富矿质的NaCl-KCl-H₂O体系。3、城门山斑岩铜钼矿的成矿母流体为高温中低盐度的超临界流体，该流体在上升过程中发生过两次明显的沸腾作用。这一过程导致成矿体系的物理化学条件发生变化，特别是导致温度突降。该变化有助于大量矿物质沉淀富集，是控制该矿形成的主要因素。4、城门山斑岩铜钼矿与世界上大型斑岩铜钼矿流体特征相似，具备大型铜钼矿的形成条件，就目前的开采情况以及成矿深度来说，其深部和边部具有成矿远景。更多还原

【Abstract】 The Chengmenshan copper deposit is located in the southeast of theJiujiang-Ruichang ore concentration area of the Middle-Lower Yangtze Rivermetallogenic belt, consisting of three ore types, namely porphyry, skarn and MassiveSulfide. This thesis focuses on the porphyry Cu-Mo deposit which is related to quartzporphyry from the perspective of fluid inclusions.The following are the major achievements obtained in this thesis.1) The formation process of Chengmenshan porphyry copper-molybdenumdeposit can be divided into the magmatic stage and the hydrothermal stage. Thehomogenization temperatures, salinity, density and pressure of magmatic stage aredefined mainly in the ranges of220-540℃,28-54wt%NaCl equiv,0.9-1.2g/cm³and3-60MPa; the hydrothermal stage are defined mainly in the ranges of220-460℃,30-45wt%NaCl equiv,1.0-1.2g/cm³and3-55MPa. The stable isotopic analysesindicated a derivation of the ore-forming fluids of the two stages from magmaticwater, while the ore-forming fluids of the hydrothermal stage mixed with a littlemeteoric water.2) The geochemical and petrographical study of fluid inclusions indicates thatthe gas component is mainly H₂O and the fliud component is mainly Cl-, SO₄^2-, F^-, K⁺,Na⁺, Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl-, Cu²⁺，Fe²⁺ and other metal ions, which indicates thatthe ore-forming fluids of Chengmenshan porphyry copper-molybdenum depositmostly belong to the NaCl-KCl-H₂O system with rich mineral.3) The fluids freshly derived from magma was high temperature and middle tolow salt supercritical ones, it had occurred twice boiling in evidence while itsintrution,which changes the physical and chemical conditions of the ore-formingsystem, especially for abrupt temperature dropping.And the abrupt temperaturedropping contribute to mineral enrichment, which is the main factor ofore-controlling.4) The fluid characteristics of Chengmenshan porphyry Cu-Mo deposit aresimilar to those of the large porphyry Cu-Mo deposits in the world, which indicates that Chengmenshan is capable to form a large copper-molybdenum deposit, andaccording to mining depth and ore-forming depth, Chengmenshan has mineralizingprospect.更多还原