西秦岭南部地形异常隆起与构造解释——兼论东昆仑断裂东段的走滑转换  

The topographical uplift of the southern part of the west Qinling Mountains and its tectonic interpretation:A discussion on the strike-slip transition at the eastern end of the east Kunlun Fault

作　　者：张波 田勤俭 朱俊文 姚赟胜 王爱国 何文贵 ZHANG Bo;TIAN Qinjian;ZHU Junwen;YAO Yunsheng;WANG Aiguo;HE Wengui(Gansu Lanzhou Geophysics National Observation and Research Station,Lanzhou 730000;Gansu 2.China Earthquake Disaster Prevention Center,Beijing 100029)

机构地区：[1]甘肃兰州地球物理国家野外科学观测研究站,甘肃兰州730000 [2]中国地震灾害防御中心,北京100029

出　　处：《第四纪研究》2022年第3期704-716,共13页Quaternary Sciences

基　　金：中国地震局地震预测研究所基本科研业务费项目(批准号:2021IESLZ06);地震科技星火计划项目(批准号:XH19045Y);科技部第二次青藏高原综合科学考察研究项目(批准号:2019QZKK0901);国家重点研发计划项目(批准号:2018YFC1503206)共同资助

摘　　要：西秦岭造山带位于东昆仑断裂和西秦岭北缘断裂的应变转换区,关于该区宏观地形地貌与构造活动的关系研究仍较薄弱。文章基于分辨率为30 m的SRTM1-DEM数据,利用ArcGIS 10.2软件的空间分析工具集(地表分析、水文分析等),提取西秦岭地区的地形地貌参数(坡度、起伏度)、流域地貌参数(流域盆地不对称度)和3条地形条带剖面,据此分析西秦岭地区的宏观地形地貌特征,结合区域活动断裂的几何图像和走滑分解,探讨西秦岭地区宏观地形地貌与构造活动的关系。研究结果如下:第一,西秦岭南部为坡度和起伏度的高值区,呈帚状散开形态,以3像素×3像素为统计单元的坡度可达86°,起伏度可达694 m;当步长为0.54 km时,西秦岭南部白龙江流域的平均地形起伏度(862 m、1104 m、1200 m)显著高于西秦岭北部的洮河-渭河流域(489 m、594 m、526 m),白龙江流域的河谷横剖面呈窄“V”形,以上结果表明西秦岭南部为地形异常隆起区,受到了强烈的构造抬升与河流下切;第二,白龙江流域盆地不对称度为67.5,远离对称状态(流域盆地不对称度=50),白龙江南西侧的流域面积远大于北东侧,说明白龙江流域南西侧受到了更强的构造抬升,发生由南西向北东的构造掀斜;洮河流域盆地不对称度为48.7,接近对称状态(流域盆地不对称度=50),洮河上游南、北两侧的流域面积相当,未受到明显的差异抬升,洮河下游西侧的流域面积明显大于东侧,说明西侧受到了更强的构造抬升,发生由西向东的构造掀斜;第三,西秦岭南部的地形异常隆起区与活动断裂图像均呈帚状散开形态,空间分布近重合,说明西秦岭南部的地形隆起与构造活动关系密切,由于活动断裂(塔藏断裂、白龙江断裂和光盖山-迭山断裂)的走向顺时针旋转,部分走滑分量转换为北东向的挤压缩短和垂向抬升分量,促使西秦岭南部发生异常强烈的地形隆起和The West Qinling Mountains is located at the strain transfer zone between the East Kunlun fault and the West Qinling fault,while the relationship between topography and tectonic activity in this zone remains poorly studied.Based on the SRTM 1-DEM data with a resolution of 30 m,this paper uses Spatial Analyst Tools(Surface,Hydrology,etc.)of ArcGIS 10.2 software to extract the topographic and geomorphological parameters(slope,range),watershed geomorphological parameters(drainage basin asymmetry),and three topographic swath profiles,based on this,we analyze the macro-topographic and geomorphological features of the West Qinling Mountains,combined with fault geometry of regional active faults and strike-slip transfer,we explore the relationship between the macro-topography and tectonic activities in the West Qinling Mountains.The research results are as follows.First,the southern part of the West Qinling Mountains is a broom-shaped high-value area of slope and range,the slope can reach 86°and the range can reach 694 m in a 3 pixels×3 pixels unit;when the statistic spacing of each swath profile is 0.54 km,the average topographic relief of the Bailong River basin(862 m,1104 m and 1200 m)in the southern part of the West Qinling Mountains is significantly higher than that of the Taohe-Weihe River basin(489 m,594 m,and 526 m)in the northern part of the West Qinling Mountains.The cross section of the Bailong River valley shows a narrow"V"shape.The above results show that the southern part of the West Qinling Mountains is an abnormally uplifted area,which has been subjected to strong tectonic uplift and river incision.Second,the drainage basin asymmetry of the Bailong River is 67.5,which is far from the symmetrical state(asymmetric factor is 50),the watershed area on the southwest side is significantly larger than that on the northeast side,suggesting tectonic tilting from southwest to northeast;the drainage basin asymmetry of the Tao River basin is 48.7,which is close to a symmetrical state(asymmetric factor is 50),while

关 键 词：西秦岭南部 地形隆起 东昆仑断裂东段 走滑转换 白龙江流域 构造掀斜 

分 类 号：P546[天文地球—构造地质学]