K-Ar age of muscovites from pelitic schists in the Neldy Formation, Makbal area, Kyrgyz Northern Tien-Shan

Abstract

Study area is located in the Neldy Formation, Makbal Complex, Kyrgyz Northern Tien-Shan. White mica in garnet and chloritoid-bearing pelitic schists shows zoning, phengite core and muscovite rim and white mica in pelitic schist shows core and rim is phengite. Obtained white mica K-Ar age of 474±12 Ma for garnet and chloritoid-bearing pelitic schists and age of 524±13 Ma pelitic schists. The age 524 represent high P/T metamorphism as first high-pressure metamorphism in the garnet and chloritoid-bearing pelitic schists. The age of 474 Ma is a mixed age corresponds as high pressure metamorphism and amphibolite facies metamorphism.