金川泥炭沉积中火山喷发物的发现及其意义  

DISCOVERY OF VOLCANIC EXPLOSION-DERIVED MATERIALS IN JINCHUAN PEAT AND ITS SIGNIFICANCE

作　　者：毛绪美[1] 洪业汤[1] 朱咏煊[1] 王华[1] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550002

出　　处：《矿物学报》2002年第1期9-14,共6页Acta Mineralogica Sinica

基　　金：国家自然科学基金资助项目 (批准号 :4973 3 10 )

摘　　要：对金川西大甸子干玛珥泥炭沉积中部一段泥砂状物质进行鉴定 ,首次发现火山玻璃 ,确定为近源火山一次爆炸式喷发的原地沉积物。在排除来自长白山天池火山和龙岗金龙顶子火山约 1 60 0a前喷发的可能性后 ,据该火山喷发物主要化学成分特点 ,推测其为龙岗火山群早于金龙顶子火山约 1 60 0aBP喷发的另一次喷发产物。据该火山喷发物所在泥炭层的年龄 ,推测这次喷发的可能年代为 1 5BC～ 2It is the first time that volcanic glass has been foud in Jinchuan peat of Xidadianzi dry maar, suggesting that the volcanic materials deposited in situ following the eruption of a near source volcano.The volcanic materials are impossible to come from the Tianchi volcano at Changbaishan, which erupted 5000 a B.P. and 800 a B.P. known, nor from the Jinlongdingzi volcano which erupted at about 1600 years ago. Because of their main chemical compositions and depletion in SiO 2, enrichment in alkalies, the volcanic materials are similar to those of the Longgang volcano group and probably come from the Longgang volcano group. According to the age of the peat in which volcanic sediments are contained, it is considered that the age of this possible earlier eruption of the Longgang volcano group is 15BC～26AD.

关 键 词：火山喷发物 西大甸子 干玛珥 金川泥炭 火山玻璃 龙岗火山群 

分 类 号：P317.3[天文地球—固体地球物理学]