腾冲、长白山年轻火山岩铀系不平衡热电离质谱法年代学研究  

Chronology of Young Volcanic Rocks of Changbaishan Tianchi and Tengchong,China,by Using the Uranium-series TIMS Method

作　　者：王非[1] 陈文寄[1] 彭子成[2] 张仲禄[1] 胡玉台[1] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]中国科学技术大学地球与空间科学系,合肥230026

出　　处：《地质论评》1999年第S1期914-925,共12页Geological Review

基　　金：国家"九五"重点项目(编号95-11)的成果

摘　　要：在国内首次建立了铀系不平衡热电离质谱法年轻火山岩年龄测定的试验流程,并研究了云南腾冲、吉林长白山天池火山岩的年龄。划分出腾冲晚更新世以来的5个喷发期次:220 ka、80 ka、20 ka、12.8～13 ka、0.75～0.79 ka和长白山天池全新世以来的3次喷发:5.3 ka、1.0ka、0.75 ka。这些年龄值和其他的方法所得的结果基本一致,表明本方法的可靠性。此外,还介绍了铀系不平衡法火山岩年代学的基本原理,讨论了样品的封闭性、火山岩中钍同位素初始组成均一性等问题。The experimental procedure of the Uranium Series Disequilibrium TIMS Method for dating volcanic rocks was set up for the first time in China, and the ages of samples from the Tengchong volcanic field, Yunnan Province, and Changbaishan Tianchi volcano, Jilin Province, were obtained. Based on this ages, the cycles of volcanic eruption can be inferred as follows: 220 ka, 80 ka, 20 ka, 12. 8～13 ka, 0. 75～0. 79 ka for the Tengchong volcanoes since the late Pleistocene and 5. 3 ka, 1. 0 ka, 0. 75 ka for the Tianchi volcano since the Holocene. All these ages are almost same as those given by variable other methods indicating that they are reliable. In addition, the principle and some problems such as closed system of the samples and homogeneity of Th isotope composition in magma are discussed.

关 键 词：腾冲 长白山 年轻火山岩年龄 铀系不平衡 热电离质谱法 

分 类 号：P597.3[天文地球—地球化学]