Zircon U-Pb Geochronology and Hf Isotopic Composition of the Xin’anzhai Granite along the Ailaoshan Tectonic Zone in West Yunnan Province
详细信息
- 责任者：Liu Huichuan (State Key Laboratory of Isotope Geochemistry ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Wang Yuejun
- 刊名：Geotectonica et Metallogenia
- 出版年：2013
- 卷期：37(1)
- 关键词：花岗岩 ; granite ; 铀—铅计时 ; U-Pb dating ; 铪同位素 ; hafnium isotopes ; 哀牢山 ; Ailao Mountains
- 页码：p.87-98
- 图表：illus., 2 tables, 61 refs.
- 分类号：0801
- issnNo：ISSN1001-1552
- isbnNo：CN44-1595/P
摘要
Summary name="EnDivSummary">A set of zircon U-Pb geochronogical and in-stiu Hf isotopic data was presented for the Xin′anzhai granite along the Ailaoshan tectonic zone in west Yunnan province. Our dating results show that zircon grains separated from the two samples (10HH-43B and 10HH-45B) from the Xin′anzhai granite yield weighted mean 206Pb/238U ages of 251.9±1.4 Ma and 251.2±1.4 Ma, respectively, which are interpreted as the crystallization age of the Xin′anzhai pluton. This indicates that the Xin′anzhai pluton emplaced at P-T boundary rather than during the Yanshanian period or late Triassic previously perceived of. Their εHf(t) values range from -9.8~-6.2 for 10HH-43B and -11.1~-3.1 for 10HH-45B with mean values of -7.6 and -6.9, respectively. The corresponding two-stage Hf model ages range from 1.67~1.90 Ga and 1.47~2.00 Ga. These data together with other observations indicate that the Xin′anzhai peraluminous biotite monzonitic granite originated from the metagreywacke in the Proterozoic Ailaoshan metamorphic complex and formed in the syn-collisional setting in response to the assemblage of the Yangtze with Simao-Indochina Blocks.