华南地质与矿产2012，Vol.28Issue(2)：124-131,8.
黄陵野马洞基性岩脉中锆石的U-Pb年龄和Hf同位素组成
Zircon U-Pb Age and Hf Isotope Composition from Yemadong Mafic Dikes in the Huangling Area
摘要
Abstract
By LA-ICP-MS methods,the U-Pb dating and Lu-Hf isotopic analysis were carried out for zircons from Yemadong mafic dikes in Huangling area,we can ascertain the forming and metamorphic age of TTG granites,and discuss whether there were some crustal remnants older than Kongling Group in the Huangling area.The Yemadong doleritic dikes intruded in the TTG gneisses,and captured many xenocrystic zircons from the country rocks.The xenocrystic zircons show the core-rim structure,the cores have magmatic oscillatory zoning,and the rims are not zoning,The thirty individual U-Pb spot analyses were done on magmatic cores of 30 xenocrystic zircon grains,and yielded three ages of 2949 Ma,2900 Ma and 2842 Ma,these indicate that the TTG granites is a complex intrusive which experiencing at least three stages of magmatism including 2949 Ma,2900 Ma and 2842 Ma.One U-Pb spot analysis was done on metamorphic rim of zircon grain,and yielded a concordant age of 2557 Ma,which is responsible for the timing of metamorphism.This provides the first demonstration for the occurrence of tectono-thermal event at about 2557 Ma,which has been connected to the Shuiyuesi movement.In the same time,the TTG granite has been metamorphism into the TTG gneisses during the tectono-thermal event resulted from the Shuiyuesi movement in the Huangling area.The xenocrystic zircons have the negative εHf（t） values of-9.85～0.89 with the average values of-4.07,and the Hf model age of 3.6～3.2 Ga,these reveals the existence of old crustal relicts with the age of 3.6～3.2 Ga rocks,which is older than the Kongling Group（3.2 Ga） in Huangling area.关键词
TTG片麻岩/基性岩脉/锆石U-Pb年龄/Hf同位素/黄陵地区Key words
TTG gneiss/mafic dike/zircon U-Pb age/Hf isotope/Huangling area分类
天文与地球科学引用本文复制引用
赵敏,魏君奇,王建雄..黄陵野马洞基性岩脉中锆石的U-Pb年龄和Hf同位素组成[J].华南地质与矿产,2012,28(2):124-131,8.基金项目
国家自然科学基金项目（编号：40972050）资助 （）
