Metamorphism Characteristics of Songduo Group in Menba Township Mozhugongka County, Tibet and the Discussion on Its Age
YANG De-ming, HE Zhong-hua, HUANG Ying-cong, ZHAO Liang, DAI Lin-na (College of Earth Sciences, Jilin University, Changchun130061, China)
Songduo Group in Mozhugongka County, Tibet had undergone deformation and metamorphism for three times. The main metamorphism (500~553, 0.93~1.15 GPa) belongs to middle-low temperature and middle-high pressure dynamo-thermal metamorphism, and is similar to the metamorphism formed in a plate collision zone. Isotope ages indicate that the Songduo Group is the product of metamorphism in Caledonian. The appearance SmNd age(1 516 Ma) of actinote schist may imply the original rocks of Songduo Group formed in middle proterozoic era.