Zircon U-Pb Age and Hf Isotope of the Gujiashan Pluton, Southeast Hubei Province: Implications for the Magma Source
详细信息
- 责任者：Xia Jinlong (Wuhan Center of China Geological Survey ; Wuhan 430205 ; China) ; Huang Guicheng
- 刊名：Geology and Mineral Resources of South China
- 出版年：2013
- 卷期：29(2)
- 关键词：铀—铅计时 ; U-Pb dating ; 花岗闪长斑岩 ; granodiorite porphyry ; 湖北 ; Hubei Province
- 页码：p.116-125
- 图表：illus., 3 tables, 44 refs.
- 分类号：0801
- issnNo：ISSN1007-3701
- isbnNo：CN42-1417/P
摘要
We report the integrated study of zircon U-Pb age and Lu-Hf isotope composition for a granodiorite porphyry sample of Gujiashan area,southeast Hubei province,in the Yangzte block.Cathodoluminescence images of zircon grains reveal that the zircons are magmatic origin,most of which enwrap inherited zircons undergone certain degree metamorphic recrystallization.The 206Pb/238U mean age of magmatic zircon is 145.4±1 Ma(MSWD=1.5),indicating Gujiashan granite porphyry formed in the Late Jurassic-Early Cretaceous.Lu-Hf isoptope compositions in magmatic zircons indicate that εHf(t)=-4.33~-17.41,two-stage model ages(tDM2) range from 1470 Ma to 2294 Ma.The 207Pb/206 Pb model ages of the inherited zircons range from 1746 Ma to 2959 Ma,mainly distributed in Paleoproterozoic and the corresponding εHf(t) ranges from-18.2 to 2.65,which yields the reworking of ancient crust and the growth of crust during Archean-Paleoproterozoic.Combinating the field geological survey,petrochemistry and the in situ analysis of zircons of Gujiashan granite porphyry,we draw the conclusion that magma source of the rock mass is Paleoproterozoic basement.Thus,it is suggested that an unexposed old basement spreads beneath the southeast Hubei province,and the entire Yangtze block,which supply new clue for the study of the Precambrian basement evolution of Yangtze block.
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