阿尔金东段断裂带流域地貌特征及其构造活动  

Fluvial Geomorphology of the Eastern Altyn Tagh and Its Tectonic Activity Implications

作　　者：路芳 高明星 周书贤 王顺 LU Fang;GAO Mingxing;ZHOU Shuxian;WANG Shun(School of Geology and Mining Engineering,Xinjiang University,Urumqi,Xinjiang 830017,China)

机构地区：[1]新疆大学地质与矿业工程学院,新疆乌鲁木齐830017

出　　处：《现代地质》2023年第5期1100-1109,共10页Geoscience

基　　金：新疆维吾尔自治区科技厅自然科学基金面上项目(2022D01C361);新疆维吾尔自治区高层次人才项目(TCBR202105);新疆大学博士启动基金(620320044)。

摘　　要：阿尔金走滑断裂带是青藏高原北缘边界主控断裂,对高原新生代地壳变形起着重要作用。本文主要以阿尔金东段走滑断裂带附近流域为研究区,利用ArcGIS软件提取并计算了173个子流域的5个地貌参数(坡度、起伏度、分形维数、面积高程积分和河长坡降指数),将各个子流域的地貌参数分为5个等级,并利用其算术平均值作为相对构造活动指数,用以定量分析研究区的地貌特征及构造活动强度。研究结果表明:阿尔金东段断裂带是整个研究区相对活动构造强度的分界线,研究区从南到北,由高山区至低山区过渡,相对活动构造指数等级逐渐降低;由相对活动构造指数等级空间分布可知,自西向东,相对活动构造强度逐渐降低,党河、野马河流域构造活动较活跃,反映该区域相对活动构造强度受区域隆升的作用明显。此外,结合岩性、降雨量及构造等因素对地貌指数的影响分析,表明构造运动是控制阿尔金东段断裂带流域地貌发育的主要因素,即地震点所处的流域、断裂带两侧的流域以及阿尔金东段断裂带与其他断裂交汇处子流域的相对构造活动强度等级均高于周围其他流域。The Altyn Tagh strike-slip fault zone is the major control fault at the northern margin of the QinghaiTibet Plateau,and plays a vital role in the Cenozoic crustal deformation of the plateau.We extracted and calculated five geomorphic indices(slope,relief amplitude,fractal dimension,hypsometric integral,and stream length gradient)of 173 sub-basins by ArcGIS software.The geomorphic indices of each sub-basin were classified into five types.Their arithmetic mean values were used as relative tectonic activity indices,in order to quantitatively analyze the topographical features and the tectonic activity intensity.We show that Altyn Tagh strike-slip fault zone is the dividing line for the relative tectonic activity intensity of the whole study area,and the relative tectonic activity index level gradually decreases from south to north,and from high to low mountainous areas.From the spatial distribution of the relative activity tectonic index grade,the tectonic activity in the Danghe and Yemahe River basins appears to be stronger,and the intensity gradually decreases from west to east.In addition,we combine the influence of rocks,precipitation,and tectonics on the geomorphic index.Our results show that tectonics is the main factor controlling the geomorphic development in the watershed of the Altyn Tagh strike-slip fault zone,the relative tectonic activity intensity in the watershed where the seismic point is located,the watershed on both sides of the fracture zone,and the stress transition zone are higher than those in other surrounding watersheds.

关 键 词：地貌参数 阿尔金断裂 相对构造活动强度 走滑断层 

分 类 号：P546[天文地球—构造地质学]