Zircon U-Pb Geochronology of Metabase Rocks from the Baoyintu Block in the Langshan Area, Inner Mongolia, and Its Tectonic Significance
摘要
The Baoyintu block of the Langshan area in Inner Mongolia is one of the oldest microcontinents in the the Xingmeng orogenic belt. Analysis of SHRIMP and LA-MC-ICP-MS zircon U-Pb ages was conducted for zircons from the metamorphic intrusive body and Baoyingtu Group. The results show a zircon U-Pb age of of 1672±10 Ma for the Baoyintu metamorphic intrusive body has and a low detrital zircon age of 1426 Ma is for the Baoyintu Group, which constrains the formation age of the Baoyingtu Group later than 1426 Ma. The comparison on the tectonic-thermal events of both the Baoyingtu Group detrital zircons and the North China Craton reveals that the Baoyintu Group is Mesoproteozoic in age and originated from the North China Craton, indicating that the Baoyintu Group is likely closely related with the North China Craton and is likely part of the North China Craton.