- 责任者：Gong Jianghua (Institute of Geology ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Zhang Jianxin
- 刊名：Acta Petrologica et Mineralogica
- 出版年：2011
- 卷期：30(5)
- 关键词：元古宙 ; Proterozoic ; 铀—铅计时 ; U-Pb dating ; 甘肃 ; Gansu Province
- 页码：p.795-818
- 图表：5 illus., 1 table, 41 refs.
- 分类号：1300
- issnNo：ISSN1000-6524
- isbnNo：CN11-1966/P
The Longshoushan Group is a part of Precambrian metamorphic basement of the Alxa block. Its origin is particularly important for constraining the western boundary of the North China Craton(NCC)and understanding the evolutionary history of China’s cratons. In this study, LA-ICP-MS U-Pb dating technique was used to determine the ages of different rocks from Longshoushan Group and Dunzigou Group. The results of detrital zircon grains from the metasedimentary rock in the Longshoushan Group gave two age populations: ~2.01 Ga and~2.15 Ga. The magmatic zircons and metamorphic zircons from the granitic gneiss yield age spans of 2.04~2.17 Ga and 1.89~1.93 Ga, respectively. These ages indicate that the Longshoushan Group was formed in Paleoproterozoic. These data imply that the southern Alxa block had an affinity with the NCC during early Precambrian period.