⁴⁰Ar-³⁹Ar Dating of the Muscovite in the Sericite of the Qimantage Ductile Shear Zone and Its Geological Significance

Qimantage ductile shear zone is the main tectonic boundary of Qimantage ophiolite belt and North Kunlun magmatic arc,we determine granitic mylonite in shear zone with sericite ⁴⁰Ar-³⁹Ar methods.Plateau age is 271.1±2.2Ma,³⁶Ar/⁴⁰Ar-³⁹Ar/⁴⁰Ar reverse-isochron curve age is 270.5±3.7 Ma(MSWD=2.7),and ³⁹Ar/³⁶Ar-⁴⁰Ar/³⁶Ar isochron age is 270.9±4.7Ma(MSWD=0.22).Plateau age 271.1±2.2Ma close to the age of mineral formation of sericite,it represents the formation age of Qimantage ductile shear zone.Through the ductile shear zone within the kinematic characteristics,dextral shear zone has the nature of Oblique filling.The formation of Qimantage ductile shear zone related Paleo-Tethys Ocean Subduction,is the remote effects of the process of Paleo-Tethys Ocean Northward subduction orogeny.