提出过剩氩的二元混合模式 ,结合实验数据定量研究过剩氩对年轻火山岩真实K Ar年龄的影响 .结果表明 :样品中含 5 %过剩氩组分对 2Ma以上的K Ar年龄影响 <7.36 % ,对 0 .5Ma的样品可使K Ar年龄升高约 32 .4% ;而 1 %的过剩氩组分则使 0 .5Ma样品的K Ar年龄升高 6 .2 6 % .因此 ,经过预处理后过剩氩成分≤ 1 %时 ,老于 0 .5Ma样品的K Ar年龄应是可信的 .利用基质测定年轻火山岩的K Ar年龄时 ,对小于 0 .2Ma的样品 ,在过剩氩含量很高的情况下 ,即便基质中只含有 1 %过剩氩组分也会对K Ar年龄产生很大影响 The binary mixed mode of excess argon was proposed and the effects of excess argon on the true K Ar ages of young volcanic rocks were quantitatively analyzed with the experimental data.The results show that the influence of 5% excess argon components on the K Ar ages above 2Ma is <7.36% For 0.5Ma samples, the KAr age was increased by about 32.4%, while the 1% excess argon component increased the KAr age of the 0.5Ma sample by 6.26%. Therefore, after pretreatment The K Ar ages of samples older than 0.5 Ma should be credible when the post-excess argon content is less than 1%. When K Ar ages of young volcanic rocks are measured by matrix, the samples with less than 0.2 Mpa are highly enriched in excess argon , Even if only 1% excess argon is present in the matrix, it can have a significant impact on K Ar age