壳幔混染成矿机制的流体包裹体证据——以滇西老王寨金矿为例  

Fluid Inclusion Evidences of Crust-mantle Mixing Ore-formation Mechanism for Laowangzhai Gold Deposit in Western Yunnan

作　　者：邓碧平[1,2] 刘万顺[1] 曾东[1] 唐东渤 武继雷[1] 缪榆辉 

机构地区：[1]新疆生产建设兵团十三师,哈密839000 [2]成都理工大学地球科学学院,成都610059

出　　处：《科学技术与工程》2015年第23期15-20,共6页Science Technology and Engineering

基　　金：国家自然科学基金(40773031);教育部高等学校博士学科点专项基金(20105122110010;20115122110005);四川省教育厅自然科学重点项目(12ZA006);成都理工大学矿物学岩石学矿床学国家重点(培育)学科建设项目(SZD0407)资助

摘　　要：深部地质过程的流体包裹体示踪显示,老王寨金矿床含矿石英中NaCl-H2O包裹体和CO2-H2O包裹体发育,含矿热液从成矿前阶段→成矿阶段→成矿后阶段,其均一温度、成矿压力、盐度与侵位深度变化依次表现为226.2～374.9 ℃→173.1 ～251.1℃→107.2 ～ 170.9℃、（827 ～1 084）×10^5 Pa→（711 ～736）×10^5 Pa→（410～460）×10^5 Pa、9.208％ ～9.857％→4.496％ ～4.651％→2.736％ ～4.651％和3.19～4.18 km→2.74 ～2.84 km→1.59～1.78 km.综合研究表明,矿区初始含矿流体主要为含CO2的地幔流体,随着成矿作用的进行,含矿热液温度、压力、盐度和侵位深度不断降低,导致成矿流体由高温熔浆性质向低温热液性质演变,从而表现出壳幔混染特征.这一深部地质演化过程反映,高温高压的含矿地幔流体,在参与成矿过程中,与地壳岩石相互作用,引发交代蚀变及壳幔物质混染叠加成矿.Fluid inclusion tracer for deep geological processes reveals that NaCl-H2O inclusions and CO2-H2O inclusions widely develop in ore-bearing quartz veins; that homogeneous temperature of ore-bearing hydrotherm varies from 226. 2 - 374.9 ℃→173.0 - 251.1 ℃→107.2 - 170.9 ℃, metallogenic pressure of ore-bearing hydro- therm varies from （827 -1 084） × 10^5 Pa→（711 -736）× 10^5 Pa→（410 -460）× 10^5 Pa, salinity of ore-bearing hydrotherm varies from 9. 208% - 9. 857%→4. 496% - 4. 651% →2. 736% - 4. 651% and that emplacement depth of ore-bearing hydrotherm varies from 3.19 - 4. 18 km→2.74 - 2. 84 km→1. 59 - 1.78 km from the pre- metallogenic stage→the metallogenic stage→the post-metallogenic stage in Laowangzhai gold deposit. Comprehen- sive studies have indicated that the original ore-bearing fluid is mainly the mantle fluid with CO2 , the temperature- pressure-salinity-emplacement of the ore-bearing hydrotherm continually lower and at the same time the ore-bearing fluid evolves from the high temperature molten lava to the low temperature hydrotherm along with mineralization, which leads to crust-mantle materials mixing. This deep geological evolution process reflects that the ore-bearing mantle fluid interacts with crustal rocks in participating in the metallogenetic course, which causes metasomatic al- teration and results in the mixture of crust-mantle materials to be favourable for mineralization.

关 键 词：深部地质过程 流体包裹体示踪 含矿地幔流体演化 壳幔物质混染叠加成矿 滇西老王寨金矿 

分 类 号：P618.51[天文地球—矿床学]