摘要
西秦岭位于青藏高原东北缘,是青藏高原向北东方向扩展的前缘地带,在中—晚新生代时期经历了复杂而强烈的构造活动。对西秦岭嘉陵江水系流域的构造地貌特征和活动程度的研究,有助于理解该地区地貌演化对青藏高原新生代隆升的响应,并在一定程度上限定其北东方向扩张的范围。本文在30 m分辨率的ASRTM DEM数据基础上,结合ArcGIS软件,对嘉陵江上游45个子流域的地貌形态进行了详细分析。采用了5种地貌指数,包括面积高程积分值(HI)及曲线(HC)、标准化河流阶梯指数(SL/K)及Hack剖面、流域盆地不对称度(AF)、盆地延伸率(Re)和河谷宽高比(VF),并计算了各子流域的相对活动构造指数(IAT)。结果表明,研究区45个子流域中,42个子流域面积高程积分介于0.35与0.6之间且积分曲线呈“S”形,表明西秦岭嘉陵江流域处于地貌演化的壮年期阶段。根据综合地貌指数分析结果,西秦岭嘉陵江地区经历了较为强烈的构造活动。在研究区的三条主要断裂中,徽成盆地南缘断裂的构造活动性最强,其次为徽成盆地北缘断裂,麻沿河断裂活动性最弱。这表明青藏高原向北东方向扩张已经影响到了西秦岭嘉陵江地区的构造变形及现代地貌的演化过程。
The Western Qinling is located at the northeastern margin of the Tibetan Plateau,serving as the frontal zone of the Tibetan Plateau's northeastward expansion.During the Middle-Late Cenozoic,the region experienced complex and intense tectonic activity.The study of the tectonic-geomorphic features and degree of tectonic activity in the Jialing River drainage basin of the West Qinling helps understand the response of the region's geomorphic evolution to the Cenozoic uplift of the Tibetan Plateau,and to a certain extent constrain the scope of the Tibetan Plateau's northeastward expansion.In this study,the morphology of 45 sub-basins of the upper reaches of the Jialing River was analyzed in detail based on 30 m-resolution ASRTM DEM data,using ArcGIS sof tware.Five geomorphic indices were used,including hypsometric integral(HI)and its curve(HC),standardized stream length-gradient index(SL/K),Hack prof ile,basin asymmetry factor(AF),basin elongation ratio(Re),and valley floor width-to-height ratio(VF);additionally,the index of relative active tectonics(IAT)was calculated for each sub-basin.The results show that 42 out of the 45 sub-basins in the study area have hyp-sometric integrals(HI)between 0.35 and 0.6 and the integration curves are“S”-shaped,indicating that theJialing River Basin in the Western Qinling is in the mature stage of geomorphic evolution.A comprehensive analysis of geomorphic indices shows that the Jialing River basin area in the West Qinling has experienced relatively intense tectonic activity.Among the three major faults in the study area,the Southern Margin Fault of the Huicheng Basin has the strongest tectonic activity,followed by that of the Northern Margin Fault of of the Huicheng Basin,and that of the Mayanhe Fault is the weakest.This indicates that the northeastward expansion of the Tibetan Plateau has already affected the tectonic deformation and evolution of modern geomorphology in the Jialing River basin area of the Western Qinling.
作者
胡金鑫
周小虎
尤继元
李勇杰
黄琪
HU Jinxin;ZHOU Xiaohu;YOU Jiyuan;LI Yongjie;HUANG Qi(State Key Laboratory of Continental Dynamics,Department of Geology,Northwestern University,Xi'an,Shaanxi 710069,China;School of Energy Engineering,Yulin University,Yulin,Shaanxi 719000,China)
出处
《现代地质》
北大核心
2025年第6期1684-1701,共18页
Geoscience
基金
陕西省自然科学基础研究计划项目(2022JM-162)。
关键词
西秦岭
嘉陵江流域
地貌指数
青藏高原东北缘
West Qinling
Jialing River Basin
geomorphic indice
Northeastern Margin of the Tibetan Plateau
