腾冲火山岩斜长石斑晶的过剩氩兼论火山活动的分期  

Excess Argon in Plagioclase Phenocryst of Tengchong Volcanics and the Related Volcano Erupting Stages

作　　者：李大明[1] 李齐[1] 陈文寄[1] 

机构地区：[1]中国地震局地质研究所,北京1000029

出　　处：《地质论评》1999年第S1期892-894,共3页Geological Review

基　　金：中国地震局"九五"重点项目(编号95-11)的资助

摘　　要：在腾冲黑空山、打鹰山和马鞍山火山岩的斜长石斑晶里首次发现存在过剩氩,并从基质中得到比以往的全岩年龄更年轻的K-Ar年龄,论证了以往所发表这一时间段的K-Ar年龄结果可能因过剩氩而偏老,结合马鞍山已经取得的10ka左右的U系年龄结果认为,腾冲最近一期火山活动的终止时间应为全新世。It has been found for the first time that excess argon exists in plagioclase phenocryst in Tengchong Heikongshan, Dayingshan and Maanshan volcanics. The K-Ar ages obtained from the matrix are younger than those of the whole rocks, which demonstrates that the published volcanic ages belonging to the Quaternary are older than their forming time because of the excess argon. Combined with the U-series dating in the Maanshan volcano, it was considered that the end time of the latest volcanic eruption in the Tengchong area was in Holocene.

关 键 词：腾冲 斜长石斑晶 过剩氩 火山活动 

分 类 号：P588.14[天文地球—岩石学]