- 责任者：Wang Jilin (Faculty of Earth Science ; China University of Geosciences ; Wuhan 430074 ; China) ; He Bin
- 刊名：Geotectonica et Metallogenia
- 出版年：2013
- 卷期：37(3)
- 关键词：变质岩 ; metamorphic rocks ; 庐山 ; Lushan Mountains
- 页码：p.489-498
- 图表：4 illus., 2 tables, 32 refs.
- 分类号：0802
- issnNo：ISSN1001-1552
- isbnNo：CN44-1595/P
The mesometamorphic strata of the Xingzi Group developed in the Lushan area, whose zircon U-Pb age of 1869i40 Ma is widely accepted, was supposed to belong to Paleoproterozoic, and experienced two stages of metamorphism. The first phase of metamorphism which reached to amphibolites facies was defined as regional metamorphism occurred in the Neoproterozoic and the second phase was dynamic metamorphism occurred in the Mesozoic. However, recent research shows that the Xingzi Group belongs to Neoproterozoic. And this result contradicts the revolution history built by previous researches. So studying the age and mechanism of the metamorphism of the Xingzi Group will have a significant influence in unveiling the revolution history of the Xingzi area and even South China. We acquire the age of 142.6±1.5 Ma（MSWD=0.49）from the metamorphic zircons in the leucosomes of the migmatite from the Xingzi Group by SIMS U-Pb method, and we advocate this age represents the time of the peak metamorphism. For this reason, we argue the regional metamorphism in the Neoproterozoic is not exactly existed. In addition, the age of 136.08±1.78 Ma obtained by Ar-Ar dating of metamorphic muscovite in the schist from the Xingzi Group also supports the conclusion above. Besides, the migmatite shows the characteristic of fluid metasomatism whose fluid might include metamorphic fluid and magmatic fluid. Combining the development of Mesozoic veins in the study area, it can be inferred that the metamorphism of the Xingzi Group might have been induced by the Mesozoic magmatic events in the Lushan area. And the mesometamorphic strata resulted from thermodynamic metamorphism. This conclusion is of great significance on rediscovering the tectonic evolution pattern of the Lushan area, especially on re-examining the Xingzi metamorphic core complex.