祁连山内部门源盆地地貌特征及构造意义  

Geomorphic features of the Menyuan basin in the Qilian Mountains and its tectonic significance

作　　者：李红强 袁道阳 苏琦 文亚猛 苏瑞欢 孙浩 陈艳文 于锦超 张梨君 LI Hongqiang;YUAN Daoyang;SU Qi;WEN Yameng;SU Ruihuan;SUN Hao;CHEN Yanwen;YU Jinchao;ZHANG Lijun(School of earth Sciences,Lanzhou University,Lanzhou 730000,Gansu,China;Faculty of Arts and Sciences,Beijing Normal University,Zhuhai 519000,Guangdong,China)

机构地区：[1]兰州大学地质科学与矿产资源学院,甘肃兰州730000 [2]北京师范大学珠海校区文理学院地理系,广东珠海519000

出　　处：《地质力学学报》2023年第6期824-841,共18页Journal of Geomechanics

基　　金：第二次青藏高原综合科学考察研究项目(2019QZKK0901);国家自然科学基金项目(42172227)。

摘　　要：祁连山位于青藏高原东北部边缘,是青藏高原向北东方向挤压扩展的前缘部位,其典型流域地貌特征记录了该地区的新构造活动和地貌发育演化过程。门源盆地是位于祁连山中段内部的一个典型的山间盆地,其发育模式和地貌特征与构造活动有着直接的关系。为探究门源盆地北缘断裂及其不同区段构造活动性的差异及其成因,文中基于30m分辨率数字高程模型(DEM)数据,采用ArcGIS空间分析技术,提取了盆地北缘横穿山体的15条河道的面积-高程积分(HI)和积分曲线(HC),再利用克里金插值法得到HI值在盆地空间上的分布特征。结果表明,以门源盆地北缘断裂走向转折处——老虎沟为界,其西侧河道流域的HI值整体较高,东侧HI值普遍较低;结合野外活动构造调查结果,发现老虎沟东侧断裂已经挤压扩展到盆地内部,并发育一系列的活动逆断层-褶皱带,由此推断断裂走向变化及北东向断裂导致了流域HI值的分布差异。同时,盆地内部青石嘴镇附近出现一处HI高值异常,结合大地电磁探测结果推测盆地内部存在一条隐伏断层。另外,多数河道在主断裂通过上游一定位置时出现了河长坡降指数(SL)峰值波动,说明SL波动位置与断裂通过河道位置具有良好的相关性,即构造活动可以对SL产生显著影响;而处于岩性变化位置附近的波动异常,可能表明局部河段的岩性变化对SL也有一定影响。综合分析表明,门源盆地北缘东、西段的地貌发育具有显著差异,主要受该区域活动构造即门源盆地北缘断裂的控制和影响,上述地貌参数是较为敏感的构造活动性评价指标。The Qilian Mountains are situated on the northeastern margin of the Tibetan Plateau and serve as the leading edge of the plateau's northeastward expansion.The Menyuan Basin,characterized by typical basin landforms,provides valuable insights into the region's neotectonic activity and geomorphic evolution.As a representative mountain basin located in the central part of the Qilian Mountains,the Menyuan Basin's development pattern and geomorphic features are closely linked to tectonic activity.This study aims to investigate the variations in tectonic activity and their underlying causes along the north margin fault and different zones of the Menyuan Basin.To achieve this,30 m resolution digital elevation model(DEM)data and ArcGIS spatial analysis technology were employed to extract the hypsometric integral(HI)and hypsometric integral curve(HC)of 15 rivers that traverse the northern edge of the basin.Subsequently,kriging interpolation was utilized to obtain the spatial distribution characteristics of HI within the basin.The findings reveal that HI values generally exhibit higher values on the western side and lower values on the eastern side of the Menyuan Basin,with the turning point(Laohugou)of the northern fault at the Menyuan Basin serving as the boundary.By combining the distribution of HI with field investigation results of active structures,it is observed that the eastern fault has extended into the basin's interior,giving rise to a series of active reverse fault–fold zones.This phenomenon may be attributed to changes in fault trends and the presence of northeastward faults.Additionally,a high HI anomaly is detected near Qingshizui Town in the basin's interior.Based on previous electromagnetic detection results,it is inferred that a buried fault exists within the basin.Furthermore,the study demonstrates that most rivers exhibit peak fluctuations in the stream length–gradient index(SL)at a specific position upstream of the main fault,indicating a strong correlation between the location of SL fluctuations an

关 键 词：门源盆地 逆冲断裂 面积-高程积分 Hack剖面 河长坡降指数 构造地貌 

分 类 号：P931.2[天文地球—自然地理学]