Research In The Features Of Neoproterozoic Metamorphic Rock Intrusion In Shengge Area

Shengge area of Qinghai province is in Northern qaidam basin tectonic belt.This articleis based on the basis of field rock assemblage, metamorphic degree, contact relationship andisotopic age data about EKen rock mass (Pt3Egn) in shengge area Qinghai province and fullyproperly apply the new theory, new method for mapping and geological research to rebuiltstructural-rock units.For that, we separate the old EKen rock mass (Pt3Egn) from the originalDa Ken Osaka terrain(Pt1D).The rock mass in the study area which toward the north, in line with regional tectonicline is divided into two zone.It mainly contains Migmatization dark clouds plagioclase gneissand Augen migmatite. Degree of migmatization from south to north is enhanced.Itsemplacement mechanism has the characteristics of active (strong) emplacement. Its tectonicenvironment is likely to be a land-continental collision incident between Qaidam landmassand Qilian landmass.In the process of collision, there is a partial melting of the crust materiallet the magma intruded along the fault,and bacome neoproterozoic gneissic rock mass.According to U-Pb test results,842±62Ma age of selected samples truly reflects the timeof the metamorphic intrusion emplacement, the intersection point of254±12Ma age agereflects the late thermal events, while1026±24Ma reflects the inheritance of theMesoproterozoic contamination, thus age of the rock should be neoproterozoic which is morereasonable.According to rock macroscopic characteristics and chemical graph analysis, the originalrock of the Neoproterozoic gneissic rock mass is calc-alkalic rock series, granitic plutonicrock.It is from crustl or crust granite (S).