Zircon U-Pb Geochronology and Hf Isotopes of the Granitic Gneisses in the Nabang Area, Western Yunnan Province
详细信息
- 责任者：Ma Liyan (State Key Laboratory of Isotope Geochemistry ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Fan Weiming
- 刊名：Geotectonica et Metallogenia
- 出版年：2013
- 卷期：37(2)
- 关键词：花岗质片麻岩 ; granitic gneiss ; 铀—铅计时 ; U-Pb dating ; 云南 ; Yunnan Province
- 页码：p.273-283
- 图表：illus., 2 tables, 49 refs.
- 分类号：0802
- issnNo：ISSN1001-1552
- isbnNo：CN44-1595/P
摘要
This paper presents the zircon LA-ICP-MS U-Pb geochronological and in-situ Hf isotopic data for the granitic gneisses in the Nabang-Tongbiguan area,Western Yunan province. Three granitic gneisses from south nabang,west and southeast of Tongbiguan have the weighted mean 206Pb /238U ages of 55. 0 ± 0. 5 Ma( 10DX-66B),50. 4 ± 1. 3 Ma( 10DX-56B) and 51. 6 ± 1. 1 Ma( 10DX-67),respectively. 10DX-66B sample gave positive εHf( t) values of 5. 2 ±1. 0 with t DM2 modal ages of 0. 63 ～ 1. 04 Ga and 10DX-67 yielded negative εHf( t) values(- 3. 8 ± 1. 1) and high t DM2ages( 1. 12 ～ 1. 55 Ga). Our data indicate that the granitic gneisses at the Nabang-Tongbiguan area were crystallized at 50 ～ 55 Ma rather than Precambrian. In combination with the available data,it is proposed that the Pan-African orogenic and Cretaceous magmatic events probably spread to the Naban area and the collision between Eurasia and India plates might have been initiated since 50 ～ 55 Ma.
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