腾冲火山区上新世以来的火山活动  

Volcanic activities in the Tengchong volcano area since Pliocene.

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,北京100029

出　　处：《岩石学报》2000年第3期362-370,共9页Acta Petrologica Sinica

基　　金：中国地震局"九五"重点项目 (95 -11)的资助

摘　　要：对腾冲火山区上新世以来的火山 ,尤其是具有最新活动的黑空山、打鹰山和马鞍山进行了比较系统的 K- Ar年龄分析。去除样品中含有过剩氩的斜长石斑晶和橄榄石斑晶以后获得了一系列准确的基质 K- Ar年龄。根据火山活动的时空变化把腾冲火山活动分为三个期。第一期为上新世晚期 ,火山活动集中于火山区的西北和东南两端 ;第二期为早更新世期间 ,火山活动向腾冲盆地中心迁移和扩展 ,活动规模和分布面积最大 ;第三期为早更新世末期至全新世 ,早更新世末期至中更新世火山活动规模逐渐减小 ,集中于盆地中部南北向条带上 ,晚更新世以来收缩于黑空山、打鹰山和马鞍山三个地区 ,马鞍山到全新世仍有岩浆活动。第三期活动的起始和终止过程在空间上呈现由中北部向南部逐渐变新的规律 。Systematic KAr Dating has been yielded for Pliocene Recent volcanic eruptions in the Tengchong volcano area, mainly for latest eruptions of Heikongshan, Dayingshan and Maanshan craters. After distignishing plagioclase phenocryst and olivine phenocryst with excess argon from samples, a series age of the matrix of volcanic rocks has been obtained. From time space exchanges and distribution, the activities of the Tengchong volcano could be divided into three stages. The first stage developed in the late Pliocene, when the volcanic eruptions occurred in southeastern and northwestern ends of the Tengchong volcano area. The second stage experienced in the early Pleistocene suggests that the volcanic activities were migrated and transferred to central areas of the basin. At this stage, volcanic scale and distribution were largest compared with that in other stages. The third stage occurred during the early Pleistocene Holocene. During the late of Early Pleistocene Middle Pleistocene, volcanic scales were decreased, and mainly distributed on a NS trending belt in the center of the Tengchong basin. Since late Pleistocene, the volcanic activities have been focused on Heikongshan, Dayingshan, and Maanshan areas. There was volcanic activity in Maanshan area in the Holocene. The third volcanic stage is characterized as from central northern to southern parts, it qets younger and younger. This means that the volcanic activities are transferred from north to south.

关 键 词：腾冲 火山活动 上新世 钾-氩年龄 

分 类 号：P317.4[天文地球—固体地球物理学] P597.3[天文地球—地球物理学]