大兴安岭中段阿尔山地区第四纪火山地貌特征及其构造意义

Geomorphological Characteristics of the Quaternary Volcanoes and Their Tectonic Implications in Aershan Region, Central Greater Khingan Range

基于资源三号(ZY-3)的高分辨率卫星影像和数字高程模型(DEM),运用地理信息系统(GIS)技术,通过遥感影像解译以及地形起伏度和坡度的定量计算,分析阿尔山火山区的地质地貌特征。共识别出19座第四纪喷发的火山,并且将其划分为5个类型。该区火山地貌按地形起伏度可分为4个类型,以低位中山为主(39.61%),其次为低位低山(36.24%)。80%的椭圆形火山锥长轴走向介于45°～75°之间,中值为58.5°,与NE向排列的小东沟火山-十号沟盆地火山-岩山-高山火山链走向平行。火山锥的马蹄形缺口主要朝向为NE向,也有SW向和NW向。NE向与SW向马蹄形缺口的角度中值相差约180°,NW向的马蹄形缺口与NW向的断裂几乎平行,推测存在控制火山喷发和展布的NE向断裂。根据研究结果推断,中生代的基底断裂使该区形成NE走向的脆弱裂隙带,为岩浆提供良好的上侵通道;裂隙控制着岩浆的上升,形成呈NE向线性分布的火山机构,并最终影响地表火山锥的分布和地貌形态。

Based on ZY-3 high resolution satellite image and digital elevation model (DEM), the authors obtained volcanic geomorphology features in Aershan volcanic region by means of satellite image interpretation, the relief degree of surface and surficial-slope analysis. According to the results of the study, 19 Quaternary volcanos were found. They could be divided into five categories. The landforms can be divided into four classes according to relief degree of surface. Low position middle mountain is the main type (39.61%), followed by low position low mountain (36.24%). 80% of the long axis direction of the elliptical volcanic cones are ranging from 45° to 75° with a median value of 58.5°. It is parallel to the NE-trending volcanic chain of Xiaodonggou volcano-Shihaogou basin volcano-Yanshan-Gaoshan. The horseshoe-shaped craters are in the direction of NE, SW and NW. The median difference between NE and SW horseshoe-shaped craters is about 180°. The NW horseshoe craters are almost parallel to NW faults. The authors predict that there are NE faults controlling volcanic eruption and distribution. Thereby an inference can be drawn that the NE-trending fractured zones were controlled by Mesozoic basement faults in the study area, and provided the channel for magma to approach. Fracture controlled the magma ascending and the formation of NE-trending volcanic apparatus, and eventually affected the distribution of volcanic cones and morphology.