- 责任者：He Zhengjun (Institute of Geology ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Zhang Xinyuan
- 刊名：Earth Science Frontiers
- 出版年：2011
- 卷期：18(4)
- 关键词：奥长环斑花岗岩 ; rapakivi ; 风化壳 ; weathering crust ; 常州沟组 ; Changzhougou Formation ; 北京 ; Beijing
- 页码：p.123-130
- 图表：4 illus., 32 refs.
- 分类号：0801
- issnNo：ISSN1005-2321
- isbnNo：CN11-3370/P
The Changchengian System serves actually as an absorbing Proterozoic research field in Chinese geological circle. Using SHRIMP and LA-ICP-MS dating methods, the authors obtained the U-Pb dating ages of (1682±20) Ma and (1 708±5.6) Ma from the detrital zircons sampled in the rocks; those age data are the same with the nearby Miyun Rapakivi Granite. Preliminary analysis has revealed that the Miyun Rapakivi granite and its synchronic dikes had once been uplifted and outcropped in the air after they were emplaced. According to the analysis of the dating results of the in-situ rapakivi-sourced sedimentary clastics and the correlative age data, the authors propose a new age of the lower limit of the Changchengian System to be about 1 665~1 670 Ma in North China.