Geological features and age of the Wenquan Rapakivi granite, Chicheng County, Hebei

Abstract：The Wenquan Rapakivi granite is distributed in the Wenquan area, Chicheng County, Hebei Province, covering an area of about 50 km2. Based on the regional geological survey of the 1:250000 Yanqing County Sheet, the authors studied the mode of occurrence and intrusive relationships of the Wenquan Rapakivi granite and discussed its age according to the petrological, geochemical and isotope age evidence. Study shows that the intrusion is A-type granite with higher contents of K, Al and Fe and lower contents of Ca and Mg. It was formed in the Mesoproterozoic, which is equivalent to the Dahongyu Stage of the Changchengian System and can be correlated with the Shachang Rapakivi granite, Miyun County, Beijing. In addition, the study also provides petrological and isotope age evidence for the study of the time of cratonization of the basement of the North China plate and event of its break-up during the Mesoproterozoic.