摘要
In this paper are reported the SHRIMP U-Pb zircon ages of the Neoarchean Zhuzhangzi and Dantazi Groups in the Qinglong area, eastern Hebei Province. Based on data obtained in this study and by others, some conclusions can be drawn as follows: 1) the Zhuzhangzi and Dantazi Groups were formed in an arc environment at the end of Neoarchean; 2) the age gap between deposition of the Zhuzhangzi and Dantazi Groups was very short although there indeed was a unconformity between them; and 3) the Zhuzhangzi and Dantazi Groups of greenschist-amphibolite facies and the Santunyun-Taipingzhaiand-Qianxi magmatic complex of amphibolite-granulite facies are different in metamorphic grade but were formed almost at the same time, being a result of late crustal movement which overthrust these deep-seated rocks to the same crustal level.