K-Ar age of young volcanic rocks and excess argon——Binary mixing model and quantitative study of excess argon effect

作     者：Darning Li Wenji Chen Qi Li 

作者机构：China Seismol Bur Inst Geol Beijing 100029 Peoples R China 

出 版 物：《Chinese Science Bulletin》 (Chin. Sci. Bull.)

年 卷 期：2000年第45卷第7期

页      面：659-664页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：China Seismological Bureau Foundation(95-11) 

主　　题：young volcanic rock K-Ar age excess argon binary mixing model. 

摘      要：A binary mixing model for excess argon is suggested in the note. According to thismodel and the data of excess argon component obtained in our experiment, a quantitative study of the effect of excess argon on real K-Ar age of young volcanic rocks is done. The result indicates that the effect of 5% excess argon component in samples on K-Ar age of the samples more than 2 Ma is less than 7.36% and can lead K-Ar age of 0.5 Ma samples to increase by 32.4%, while 1% excess argon component leads K-Ar age of 0.5 Ma samples to increase by 6.26%. Therefore, when pre-processed excess argon component is ≤1%, K-Ar age of the samples more than 0.5 Ma should be credible. On this basis we suggest a principal opinion for evaluation of previous K-Ar dating results and propose that the matrix is used to determine K-Ar age of young volcanic rocks. For the samples less than 0.2 Ma, in the case of high excess argon content, even if only 1% excess argon component exists in their matrix, it can also greatly affect their K-A