Zircon U-Pb Age and Petrogenesis of Intrusions from Mengzi Area in the Northern Margin of Yangtze Plate
详细信息
- 责任者：Xu Xueyi (Xi’an Center of Geological Survey ; CGS ; Xi’an 710054 ; China) ; Li Ting
- 刊名：Acta Petrologica Sinica
- 出版年：2011
- 卷期：27(3)
- 关键词：侵入体 ; intrusions ; 铀—铅计时 ; U-Pb dating ; 扬子地台 ; Yangtze Platform
- 页码：p.699-720
- 图表：8 illus., 3 tables, 63 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The combined U-Pb and Lu-Hf in situ LA-ICPMS analyses of zircons and the geochemistry studies reveal that the gabbronorite, bojite, granodiorite, quartz diorite and moyite along the northern margin of the Yangtze Plate are all formed during the Middle-Neoproterozoic and Late-Neoproterozoic. The analysis reflects that the gabbronorite and bojite have experienced significant crustal contamination, most likely Meso-proterozoic crustal contamination. Besides, the quartz diorite is formed at (774±34) Ma. The granodiorite and quartz diorite are calc-alkaline series, both of them have similar geochemical features and are rich in LILE and depleted in HFSE. The results shows that the moyite is the produce of the partial melting of ancient crust with little additions of Neoproterozoic juvenile crust. Consistent with the characteristics of regional geology, the intrusions are formed in an active continental margin tectonic setting, which is the geological record of south-directed subduction by Mianlue oceanic crust in Neoproterozoic.