摘要
冀东高级变质的石榴石斜长片麻岩、含或不含石榴石的角闪二辉斜长片麻岩、紫苏花岗岩、斜长角门岩等岩石中的流体包裹体主要有４类，按形成的先后顺序依次为：（１）Ｈ２Ｏ和ＣＯ２两液相包裹体，ＣＯ２的部分均一温度是－１２℃，密度１．０４ｇ／ｃｍ３，Ｈ２Ｏ含量２１％～３９％（ｍｏｌｅ％），ＣＯ２含量５０％～７１％（ｍｏｌｅ％）；（２）ＣＯ２液相包裹体，冰点温度－５６℃～－６１℃，均一温度－７．４℃～－３５．１℃，ＣＯ２密度约为１．０５ｇ／ｃｍ３，ＣＯ２含量８２．１％～９８．４％（ｍｏｌｅ％），还有少量的ＣＨ４、Ｎ２和Ｈ２等组分；（３）Ｈ２Ｏ和ＣＯ２多相包裹体，ＣＯ２的部分均一温度７℃～２８℃，ＣＯ２密度为０．６４～０．９３ｇ／ｃｍ３，气相组分以ＣＯ２、ＣＨ４和ＣＯ为主，液相成分主要是Ｈ２Ｏ和ＣＯ２；（４）多世代盐水溶液包裹体，冰点温度－０．５℃～－２０℃，盐度０．８７％～２２．８％（ｗｔ％），盐水密度０．７～１．０５ｇ／ｃｍ３，均一温度在１５０℃～２００℃和约３００℃，存在两个峰值。不同世代的流体包裹体记录了等密度降温的Ｐ－Ｔ路径。包裹体反映的变质作用早期降温过程流体的Ｈ２Ｏ／Ｈ２Ｏ＋ＣＯ２（ｍｏｌｅ）比值降低。
Fluid inclusions from high grade metamorphosed garnet plagioclase gneisses, garnetbringfree honblende two pyroxene gneisses, charnockite, amphibolite and trondhjemites in East Hebei province can bedivided into four types by trapped order. The first type is H2O and CO2 two liquid phase inclusions, in whichCO2 partial homogenization temperature is-12℃, density 1. 04g/cm3 and H2O content about 21 %～39%(mole% ). The second type is CO2 liquid phase inclusions with freezing temperature of-56℃～61℃, homogenization temperature of-7. 4℃～-35. 1℃, CO2 density about 1. 05g/cm3 and CO2 content 82. 1～98. 4 %(mole), having a little of CH4, N2 and H2. The third type is H2O and CO2 multiple phases inclusions in whichCO2 partial homogenization temperature is about 7℃～28℃ and CO2 density 0. 64～0. 93g/cm3. In this type offluid inclusions, CO2, CH4 and CO are major components in gas phase and H2O and CO2 in liquid phase. The lasttype is multiple generations brine inclusions in which freezing temperature is -0. 5℃～20℃, salinity 0. 87 %～22. 8% (wt% ) and brine density 0. 7～1. 05g/cm3. Their homogenization temperature shows two peaks at150℃～200℃ and about 300℃. Fluid inclusions in different generations record isodensity decreasing temperature P-T paths. H2O/H2O+CO2 (mole) ratio reduces from peak metamorphism to earlier decreacing temperaturemetamorphic processes, but this ratio increases in late retrograde metamorphism and uplifting processes.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第4期375-385,共11页
Acta Petrologica Sinica
基金
博士后基金
关键词
变质岩
液包体
岩石样品
High grade matamorphic rock
Inclusions
Fluid composition
P-T path
East Hebei Province
