Crustal Anatexis in the Tongbai Orogen: Evidence from LA-ICP-MS Zircon U-Pb Age of Migmatite
详细信息
- 责任者：Liu Xiaochi (State Key Laboratory of Geological Processes and Mineral Resources ; Faculty of Earth Sciences ; China University of Geosciences ; Wuhan 430074 ; China) ; Wu Yuanbao
- 刊名：Acta Petrologica Sinica
- 出版年：2011
- 卷期：27(4)
- 关键词：深熔作用 ; anatexis ; 混合岩 ; migmatites ; 铀—铅计时 ; U-Pb dating ; 河南 ; Henan Province
- 页码：p.1163-1171
- 图表：4 illus., 1 table, 50 refs.
- 分类号：0802
- 出版序号：845
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The Tongbai orogen is a key region to investigate the evolution of the Qingling-Tongbai-Dabie-Sulu metamorphic belt. Three migmatite samples from the Tongbai complex, including one melanosome and two leucosomes, were selected for LA-ICPMS zircon U-Pb dating. The protolith formation age might correspond to magmatism during the Mid-Neoproterozoic in the northern margin of South China Block. On the other hand, new growth zircons in the leucosome samples show planar or weakly oscillatory zoning, low Th/U ratios. The morphological and internal structure features of zircons suggest that their growths were associated with partial melting. The timing of the anatexis in the Tongbai high-grade metamorphic complex is coeval with the widespread post-collision magmatism in the Tongbai-Dabie orogen. It suggests that the onset of extensional tectonism in the Tongbai orogen is no later than 135 Ma.
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