Characteristics Of Metamorphic Rock Series And It's Fluid Inclusions From Jinshuikou In Eastern Kunlun

The research of metamorphic rocks,in eastern Kunlun,had begun with regional geological survey since 1960 to 1980.Baishahe metamorphic rocks series attracts many geologist's notice because it is considered the one of oldest rock of eastern Kunlun.Baishahe has zonal wide distribution and suffered amphibolite-granulite facies metamorphism whose grade was more intensive in west and weaker in eastern.The metamorphic grade of Qingshuiquan,Jinshuikou,Bairiqiligou and Tiantaishan reached granulite facies in where was found granulite and Al-rich gneiss of granulite facies.The granulite facies Al-rich gneiss has the metamorphic assemblage of Cord+Gt+Sill+Bi+Kf+Pl+Q that is the character of low pressure granulite facies metamorphism.The age of granulite facies metamorphism of Baishahe rock series is early Paleozoic rather than early Proterozoic,it was certified by zircon SHRIMP age of from Al-rich gneiss.Thus it can be seen a important structure-heat event in eastern Kunlun,the result of the event is that has reset old formation of petrology and system of isotope. Metamorphic fluid research related early Paleozoic granulite facies metamorphism in eastern Kunlun Mountains is blank,therefore going on the system research to the Paleozoic metamorphism characteristic and the metamorphic fluid,opening out the metamorphic fluid origin,the migration,the rock-fluid affects,as well as eastern Kunlun Mountains orogenic zone p-T path and so on is a quite vital significance. This research work designated Baishahe metamorphic rock series from Jinshuikou this typical area as a goal,from the petrography,the geochemistry, the isotope chronology,to the research of fluid inclusions,discusses Early paleozoic metamorphism characteristic of metamorphic rock series from the Jinshuikou,the age,the metamorphic fluid ingredient characteristic and its evolution. We can draw the following conlusions from the researchs of metamorphic petrology and fluid inclusions of Jinshuikou's metamorphics series: 1. Baishahe metamorphics series from Jinshuikou had suffered granulite facies metamorphism in early eopaleozoic(460Ma).Qingshuiquan,Jinshuikou,Bairiqiligou and Tiantaishan of easternern Kulun were underwent the granulite facies metamorphism,Baishahe metamorphics from these regions reach the scope of temperature and pressure of granulite facies.Granulite facies metamorphism character as appearance of Cord±(Gt)+Bi+Pl+Kf+Q from politic metamorphics,appearance of Fo+Phl+Ca from carbonate rock and appearance granulites form regions such as Qingshuiquan,Jinshuikou ,Bairiqiligou and Tiantaishan of easternern Kulun.Isotopic ages,which are SHRIMP U-Pb of zircon from Jinshuikou,Bairiqiligou,make clear that large-scale anatexis is impossible during granulite facies metamorph-ism,Extensive anatexis had occered 40-60Ma after 460Ma. 2. Granulite in Jinshuikou defferent with other granulites on low K ,Na,unconspicuouly negative of Rb.Character of Sr-Nd show that granulite is the result of metamorphic crust and. 3. Decompression was obvious during the ganulite facies metamorphism because garnet widely has reaction rim of cordierite.Temperature of metamorphics was worked out at 850℃of two pyroxene geothermometer of basic granulites.Pressure was worked out at 6KBar-4KBar from mineral assemblage of metapelites. 4. Fluid inclusions of metamorphic rocks from Jinshuikou can be classify the following five stag:Ⅰp rimary CO2-rich fluid inclusions during peak stage of granulite-facies metamorphism,ThCO2=-2.5℃～7.2℃; Ⅱsecondary CO2-rich fluid inclusions which has more CH4 than first stage,it's ThCO2 is -2.5℃～7.2℃;ⅢH2O-rich fluid inclusions that belong to system of H2O-CO2 ,the particl homogenization temperature of CO2 is TCO2=17.3℃～25.2℃,the finally homogenization temperature of inclusions is 290～394℃;ⅣSecondry...