| In recent years, fluid inclusion and structure are getting closer. Tectonite or fluid inclusion of syntectnic-hydrotherm vein are just like the"black gaine", they record the evolution of the fault and the paleo- circumstance.The Daqingshan overthrust structures are located in the east inner Mongolia Baotou city, the middle area of Daqingshan orogenic belt. There is Rift-Subsidence Basin in the side of the The Daqingshan overthrust structures. The Daqingshan overthrust structures are part of Yinshan fault-uplift of North China Craton. From Trias to Cretaceous, The Daqingshan overthrust structures, which were composed by a series of tectonic slice from south to north, were built slowly in the Pulsative Orogenic Process including times deformation. In the view of texture, The Daqingshan overthrust structures were composed four tectonic belt or tectonite slice zone dividing up by three backbone fault.. The four tectonic belt are the outer tectonic belt, the north front extrusion belt, meddle inclined-overturned folds and thrust belt, and south metamorphic thrust belt. In the paper, combining some research result of this area, we focus on the The Daqingshan overthrust structures and figure out new result, as follows: 1. The thrusting tectonics in Daqingshan region can be divided into two periods. The earlier happened in the Indo-Chinese epoch and the thrusting deformation action of the Indo-Chinese epoch happened from 228 to 193Ma. The later happened in the Stage of Yanshan and 121.6±1.6Ma could represent the time of thrusting deformation action of the Stage of Yanshan. The Stage of Yanshan can be divided into two stages further, the first stage happened from Late Jurassic epoch to Lower Cretaceous, and the second stage happened in advanced stage of Lower Cretaceous or later.2. The first stage was Indosinian crust Thrust-nappe metamorphism. According to the study on the fluid inclusions, it is suggested that in this stage (there is daughter crystal-bearing 3-phase and aqueous 2-phase, and pure gas and pure aqueous phase in the quartz vein) the range of the temperature of aqueous 2-phase is from 108.1 to 228.4℃,and the peak value is between 120 to 150℃(Bb2—3);temperature from 95.7 to 263.7℃with peak value between 120 and 250℃(Bb3—1); and from 92.3 to 157.6℃with peak value between 95 and 135℃(BY3). The salinity ranges from 3.2 to 8.1 wt﹪NaCl, and the peak value is from 5.0 to 7.0wt﹪NaCl(Bb2—3);from 2.1 to 6.9 wt﹪NaCl,with majority from 3.4 to 5.7 wt﹪NaCl(Bb2—3)and from 3.9 to 17.3 wt﹪NaCl(BY3) separately. Similarly, the temperature of 3-phase fluid inclusions is from 246.6 to 372.1℃,with peak value from 320 to 345℃(Bb2—3); range from 222.2℃to 314.4℃with peak value from 240 to 300℃(Bb3—1)and between 257.5 and 373.2℃with peak value from 273.2 to 318.9℃.The second stage is the first period of Yanshanian crust Thrust-nappe metamorphism in late Jurassic. According to the study on the fluid inclusions, it is suggested that the range of the temperature of aqueous 2-phase is from 110.3℃to 180.9℃, and the peak value is between 130℃to 160℃ (Bb2—1);temperature from 130.2 to 160.9℃with peak value between 135 and 155℃(Bb2—2); and from 100.8 to 260.7℃with peak value between 200 and 250℃(Bb5—1). The salinity ranges from 4.2 to 12.5wt﹪NaCl , and the peak value is from 4.5 to 6.9 wt﹪NaCl;from 2.9 to 8.3 wt﹪NaCl,with majority from 2.7 to 5.7 wt﹪NaCl. separately.The third stage is the second period of Yanshanian crust Thrust-nappe metamorphism in at the end of early Cretaceous or later. According to the study on the fluid inclusions, it is suggested that in this stage ,the range of the temperature of aqueous 2-phase in calcite vein is from 78.0℃to 260.4℃, and the peak value is between 130℃to 160℃(Bb2—1);temperature from 130.2 to 160.9℃with peak value between 85 and 110℃. The salinity ranges from 2.6 to 4.8 wt﹪NaCl; in quartz vein (including CO2) is from 169.8 to 200.3℃, with salinity from 2.9 to 4.2 wt﹪NaCl; and in quartz vein (barring CO2) is from 94.3 to 110.7℃, with peak value between 95 and 105℃. Accordingly, the salinity ranges from 3.1 to 5.7 wt﹪NaCl.3. The evidences of stable isotope shows that the fluid of the first period mainly comes form deeper and probablely it comes form mantle or lower crust; the fluid of second period mainly comes from atmospheric precipitation; the C of the fluid of third mainly comes from sedimentary carbonas.4. Comprehensive study on fluid inclusion (including measurement of tempreture , after-testing data analysis and mapping)indicated that Daqingshan thrust nappe structures can be divided into three stages,concord with the stages established by regional geological data with strata relationship and occurrence of ore bodies. These two are inter-identified.An other evidence to establish structure stages and evolution sequence is as follows: the sample Bb-3(carbonate lode) consists of quartz which can also be characterized into two types:one concludes CO2 inclusions with relitively higher tempreture of gas and fluid phases whereas the other with no CO2 inclusions and relitively lower temperture of both phases. Results from testing implied that the region had gone through three structure-thermal stages: the early stage with high tempreture and CO2 inclusions;the second stage with relitively lower tempreture and the last one with intruding cabonite lodes.5. According to the uniform temperature and salinity of fluid inclusion, utilizing the conversion expressions between pressure and depth, we conclude that the temperature falls,pressure diminishes and depth shoals when the fault was forming from the first to the third phase of thrust nappe structures in Daqing mountain.
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