Methods for Choosing Target Points In-situ Zircon U-Pb Dating
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摘要: 锆石微区原位U-Pb定年时,测定位置的选择至关重要,直接影响锆石测年结果.锆石内部结构研究是锆石测定位置选择的重要依据,本文结合不同成因锆石的内部结构特征及其年代学意义,总结了岩浆锆石、变质锆石、热液锆石以及蜕晶化锆石的测定位置选择方法,认为组成单一的岩浆锆石是理想的U-Pb定年对象,对于成因复杂的锆石尽量选取单一成因的颗粒或晶域,避免跨晶域选择测定位置.对于跨晶域选择测定位置测定得到的年龄结果必须做适当的(如不一致线的方法)校正,才可以用于地质成因的解释,否则得到的是没有地质意义的混合年龄.Abstract: Choosing the target points in the testing zircons is very important as it directly affects the zircon dating results during the in-situ zircon U-Pb dating.In this paper,the methods of choosing target points were summa-rized for magmatic zircons,metamorphic zircon,hydrothermal zircon and metamictization zircons based on their internal structure and the Geochronology.The conclusion is that magmatic zircons with simple composition are ideal minerals for zircon U-Pb dating.The simple genetic zircon grains or crystal domains are chosen for the com-plex zircon.The results abtained from across-domains can only be used after correction by inconsistent line,oth-erwise,it is meaningless.
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Key words:
- in-situ /
- zircon U-Pb dating /
- choosing the target point
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