内蒙中部辉腾锡勒第四纪火山群初步研究

辉腾锡勒火山群位于内蒙古中部卓资县、察哈尔右翼中旗和后旗交界处的高山草原区。处于中国东部大同-阿尔山-诺敏河第四纪火山喷发带南段。火山群坐落在太古宙变质岩系、二叠纪花岗岩和新近纪汉诺坝玄武岩之上。平面上呈低洼的菱形台地,四周为山地,总面积约260km²。因上覆在汉诺坝玄武岩台地之上,故以往将其误归为新近纪汉诺坝玄武岩。火山群内发育近百座火山,大多数火山形貌保存基本完整。火山产物主要为一套碱性橄榄玄武岩,次为不同成因的火山碎屑物（岩）。碱性玄武岩覆盖在晚更新世坡积物和黄土之上。火山活动的时代主体为晚更新世,可进一步分为早、中、晚三期。早期为裂隙-中心式喷发,火口已剥蚀殆尽;中期主要形成"地池式"和玛珥式火山,火山形貌较完整,火口呈特征的圆形或椭圆形,大部分积水成湖,当地习称"九十九眼泉"或"海子"。晚期以熔浆的溢流为主,形成结构完整的盾片状火山。火山活动经历了沿裂隙的喷溢到中心式弱爆发、溢流-射汽岩浆爆发-溢流再到溅落堆积的演化过程。辉腾锡勒火山群是在新近纪汉诺坝玄武岩台地上新解体确定的第四纪火山群,这为研究蒙古高原南部地壳深部结构及其活动性提供了又一天然窗口,对了解新构造活动、环境及灾害预警研究都具有重要的理论和实际意义。

Preliminary study on Quaternary volcanic cluster in Huitengxile, central Inner Mongolia

Huitengxile volcanic cluster is located at the junction of Zhuozi County, Chahar Right-Middle and Right-Back Banners, central Inner Mongolia, situated in the alpine grassland area. It belongs to the southern part of the Quaternary volcanic eruption belt of Datong-Arxan-Nuomin River in the east of China. The volcanic cluster is located on the Archean metamorphic rock series, Permian granites and Neogene Hannuoba basalts. On the plane, it is a low-lying diamond platform surrounded by mountains, with an area about 260km². Because it is superimposed on Hannuoba basalt platform, it was mistakenly classified as Neogene Hannuoba basalt in the past. There are above 100 volcanoes in the volcanic cluster, most of which are basically intact. The volcanic products are mainly alkaline olivine basalts, followed by pyroclastic materials (rocks) of different genesis. The alkaline basalts are overlying the Late Pleistocene slope deposits and loess. The volcanic activity is mainly in the Late Pleistocene, which can be further divided into three stages:early, middle and late. In the early stage, it was fissure-central eruption, and the crater had been denuded completely. In the middle stage, it mainly formed "Dichi-type" and Maar-type volcanoes, with relatively complete volcanic morphology. The craters were characterized by round or oval shapes, most of which accumulated water into lakes, commonly known as "ninety-nine eye springs" or "Haizi". In the late stage, lava overflowed and formed shield volcanoes with complete structures. The volcanic activity has experienced the evolution process of extrusive, center-type weak eruption and overflow, phreatomagmatic eruption, overflow and then sputtering along the fractures. Huitengxile volcanic cluster is a Quaternary volcanic cluster newly disintegrated on the Hannuoba basalt platform of Neogene, which provides another natural window for the study of the deep crustal structure and its activity in the south of the Mongolian Plateau, and has important theoretical and practical significance for studying neotectonics, environment and disaster warning.