内蒙锡林浩特鸽子山火山地质研究  

Study on the geology of Gezi Shan volcano in Xilinhot,Inner Mongolia

作　　者：杨若昕[1] 白志达[1] 谭庆伟[2] 吴之理[2] 王妍[1] 

机构地区：[1]中国地质大学,北京100083 [2]内蒙古国土资源厅,呼和浩特010011

出　　处：《岩石学报》2012年第4期1181-1188,共8页Acta Petrologica Sinica

基　　金：国家地震局公益性科研专项(20007-8-27-13);内蒙古国土资源厅地质遗迹保护专项(2010-1030)联合资助

摘　　要：鸽子山火山位于内蒙古自治区锡林浩特市东南,处于大兴安岭-大同新生代火山喷发带中段,是锡林浩特-阿巴嘎火山群中保存最为完好的一座玄武质火山。火山喷发物的分布面积约55km2,主要为降落火山渣、溅落熔结火山碎屑岩和熔岩流,成分主要为碧玄岩,晚期有少量的橄榄拉斑玄武岩,碧玄岩中含有较多二辉橄榄岩包体和辉石及歪长石巨晶。火山由锥体、熔岩流和火山碎屑席组成,锥体由早期的降落锥和晚期溅落锥复合而成。火山口经历多次塌陷而成为破火口。锥体西侧及北东侧出露两个仍保留了原始形态的熔岩溢出口,熔岩流类型为结壳熔岩,由多个岩流单元组成,局部地区的熔岩流中发育较多保存完好的喷气锥、喷气碟或喷气塔。火山碎屑席主要分布在锥体的东侧,厚度由锥体向外逐渐减薄。火山活动可分为早、晚两个阶段,早期为爆破式喷发,形成火山渣锥和碎屑席,属亚布里尼型喷发,晚期主要为溢流式喷发,形成溅落锥和大规模熔岩流,其活动时代为晚更新世末-全新世。Gezi Shan volcano is located in the southeastern Xilinhot of XilinGol League in Inner Mongolia Autonomous Region and tectonically belongs to the central part of Daxing＇anling-Datong volcanic belt,It is the most intact basaltic volcano in the Xilinhot-Abaga volcanic cluster,The distribution area of the volcanic products is about 55km2,The main products of Gezi Shan volcano are landed scoria,splashdown welded pyroclastic rock and lava flows,They are main basanites,with minor late-stage olivine tholeiites,The basanites contain abundant lherzolite xenoliths,pyroxene and anorthoclase megacrysts,Gezi Shan volcano comprises volcano cone,lava flows and volcano clastic seats,The volcano cone is the composite of early landed cone and later splashdown cone,The crater was changed into a typically broken crater due to multiple collapses,Two lava overflow ports,which still keep their original forms,are observed in the west and the northeast sides of the cone,The type of the lava flows is encrustant lava,composed of several lava flow units,There are lots of well-kept fumarolic cones of different kinds in some parts of the lava flows,Clastic seats in the volcano are mainly distributed in the east side of the cone,The further from the volcano cone,the thinner the volcano clastic seats are,The volcanic activity of Gezi Shan can be divided into two stages,The volcanic activity during early stage was explosive eruption and produced the landed scoria cones and the clastic seats,The eruption belongs to week-brinley type,Late-stage volcanic activity was overflow eruption and produced the splashdown cones and massive lava flows,The eruption era of the Gezi Shan volcano is the end of Late Pleistocene to Holocene.

关 键 词：鸽子山火山 碧玄岩 亚布里尼型 全新世 锡林浩特 

分 类 号：P588.145[天文地球—岩石学]