The Emplacement Temperature And Pressure Conditions Of Late Triassic Granites In Qinling Orogen And Their Geological Significance

The intensely collision orogeny during the Indosinian period laid the basic tectonic framework of the Qinling orogen and developed a large number of granitic plutons.During last two decades many geochronology and geochemistry studies have been carried out on these Late Triassic granites.However,little attention has been paid to the temperature and pressure conditions of granite emplacement and the dynamic process of emplacement uplift of rock mass.This thesis select the representative granite plutons in the Qinling orogeni as the main research objects,such as the Mishuling pluton,the Dongjiangkou pluton,the Laojunshan and the Qinlingliang plutons.By means of amphibolite-plagioclase thermometer and biotite pressure gauge,the conditions of temperature and pressure in the process of emplacement of rock mass are defined,fluid inclusion microthermometry limits the process of fluid evolution after rock mass emplacement and emplacement,to ensure the depth of the granite emplacement,the physical and chemical state of the emplacement of the rock mass,and the related processes of uplift.And research the relationship between emplacement uplift process and regional structure of rock mass.In order to provide key constraints for the emplacement uplift process of the late Triassic granitic plutons in the Qinling orogeny.There are some results and awareness as follows:(1)pluton intrusive depth,Mishuling 9.5~16.6 km,Dongjiangkou 5.6~10.9 km,Qinlingliang 6.6~12 km,Laojunshan 4.8~8.9 km;(2)surface uplift thickness,Mishuling 6.5 km,Dongjiangkou 3.8 km,Qinlingliang 4.5 km,Laojunshan 3.4 km;(3)denudation thickness,Mishuling 7.5 km,Dongjiangkou 4.7 km,Qinlingliang 5.3 km,Laojunshan 4 km;(4)The Mishuling pluton rises rapidly to the surface of the earth's surface less than 50 Ma after emplacement,the rate of surface uplift is 130 m / Ma,the rate of erosion is 150m/Ma.