东营凹陷平南地区火山岩中发现含石盐子晶流体包裹体及其对岩浆脱气的启示  

The Discovery of Bearing Halite Daughter Minerals Fluid Inclusions in Volcanic Rocks at Pingnan Area in Dongying Depression and Implications to Magma Degassing

作　　者：陈勇[1] 周瑶琪[1] 肖焕钦[2] 任拥军[1] 孙锡年[3] 王强[1] 颜世永[1] 刘超英[1] 

机构地区：[1]中国石油大学地球化学与岩石圈动力学开放实验室,山东东营257061 [2]中国石化胜利油田勘探处,山东东营257015 [3]中国石化胜利油田地质科学研究院,山东东营257015

出　　处：《地质学报》2006年第11期1699-1705,共7页Acta Geologica Sinica

基　　金：国家973项目(编号G199043302);中国石油大学研究生院创新基金项目(编号B2004-05);胜利油田科技攻关项目子课题"平南油田油气成藏模式研究"资助成果(编号M040118)资助的成果

摘　　要：本文报道在东营凹陷平南地区滨古斜15井火山岩岩心中发现含石盐子晶流体包裹体。流体包裹体赋存于石英闪长玢岩的石英矿物之中，经显微观察和-185℃低温原位拉曼光谱分析．确定子晶为石盐矿物。显微测温分析结果显示．原生包裹体的均-温度在359～496℃，流体的盐度为43．26%～54．51％。研究样品中5种类型流体包裹体共生．说明流体发生了不混溶作用。岩浆上升过程中温度和压力的降低导致流体发生强烈的不混溶作用．并促进岩浆脱气。由于富CO2流体以岩浆脱气的方式逃离岩浆．而高盐度流体作为脱气之后的残余流体保存在包裹体中．所以包裹体中以高盐度流体（NaCl-H2O体系）为主，而另一端元组分（富CO2流体）较少。含石盐子晶流体包裹体的发现证实平南地区岩浆中存在高盐度流体．研究结果表明该区的岩浆脱气过程与高盐度流体不混溶作用有关。这个发现对进一步了解岩浆脱气机制和中国东部无机成因CO2成藏有重要的启示意义。This paper has reported the discovery of bearing halite daughter mineral fluid inclusions in volcanic rocks at Pingnan area in Dongying depression. The samples were collected from BGX-15 well drill cores and the interested fluid inclusions are hosted in quartz of diorite-porphyrite. The daughter minerals are NaCl crystals which were identified by observation under microscope and analyzed by in situ Raman spectroscopy at -185 ℃. The results of micro-thermal analysis show that the homogenization temperatures of primary fluid inclusions are between 359℃ and 496℃, and the salinities of fluid inclusions are from 43. 26% to 54. 51%. All fluid inclusions in studied samples can be divided into five types including primary fluid inclusions and secondary fluid inclusions. Five type fluid inclusions were symbiotic in a same quartz grain, which imply that immiscibility happened in magma. Due to the decreases of temperature and pressure during magma ascending, the fluids became intensively immiscible. This process will accelerate degassing of CO2 from magma, and the result of the CO 2-rich fluids had got away from magma by degassing, but the remnant fluids with high salinity were saved in fluid inclusions. So, the primary fluid inclusions are mainly in NaCl-H2O fluids, poor in CO2. The results of our study indicate that the degassing of magma and accumulation of CO2 gas at Pingnan area are relative to the immiscibility of high salinity fluids. This discovery is important degassing and accumulation of inorganic CO2 in eastern China.

关 键 词：石盐子晶 流体包裹体 岩浆脱气 不混溶作用 东营凹陷 平南地区 

分 类 号：P588.14[天文地球—岩石学]