地貌形态指标揭示的北天山乌鲁木齐河流域新构造活动特征  

NEOTECTONIC ACTIVATION OF THE URUMQI RIVER BASIN REVEALED BY GEOMORPHIC INDICES

作　　者：武登云[1] 张天琪[1] 程璐[1] 王振[1] 吕红华[1] 郑祥民[1] 

机构地区：[1]华东师范大学地理科学学院地理信息科学教育部重点实验室,上海200241

出　　处：《第四纪研究》2018年第1期193-203,共11页Quaternary Sciences

基　　金：国家自然科学基金项目（批准号：41371031）和国家理科人才培养基地项目（地理学）（批准号：J1310028）共同资助

摘　　要：如何从现有的地貌形态定量提取构造活动信息是构造地貌研究的重要内容。乌鲁木齐河是天山北麓发育的主要河流之一，构造上可分为天山主脉、后峡断陷、南山隆起和山前坳陷等4个构造分区。本文运用河流坡降指标sL和Hack剖面以及标准化坡降指标SL／K等地貌计量指标，结合地层岩性等信息，探讨了乌鲁木齐河流域4个构造分区的新构造活动特征。结果显示，乌鲁木齐河流域干流全河段Hack剖面形态上凸，同时均衡坡降指标值（K）较高（K=531），表明其目前构造仍较为活跃；天山主脉和南山隆起分区于流河段Hack剖面曲线形态表现为上凸，显示分区内部处于相对强烈的构造隆升状态；后峡分区除局部因规模较大的支流汇入导致干流河段SL／K异常偏高外，其整体Hack剖面曲线形态趋于下凹，表明其内部构造活动性较弱；在南山隆起和山前坳陷过渡带，受准噶尔南缘断裂带的影响，干流河段的Hack剖面曲线形态表现为“上凸下直”，表明这部分河段目前尚处在向新均衡剖面调整的阶段；乌鲁木齐河流域干流河段SL／K在多处出现了异常高值，研究表明这和构造活动、岩性改变、支流汇入有关。How to extract tectonic activity information from the existing geomorphic form is an important part of geomorphic research. The river slope index SL can indicate the local slope of the longitudinal profile of the river, and is often used to discuss the problem of tectonic activity （fault） or lithology difference. The Hack profile can reflect the changes in the longitudinal profile of the river and is often used to indicate the structural movement of larger time scales. In this paper, we choose the stream length-gradient SL index, Hack profile and gradient index （SL/K）with the method of ArcGIS statistical analysis technology to interpolate the basin K value and meanSL/K value. Combining the spatial distribution characteristics of the K value and the meanSL/K value with the lithology, we discusses four partitions tectonic division of neotectonic activity and landform evolution stage of the Urumqi River. The Urumqi River is one of the main rivers in the northern Tian Shan foreland, which flows through the Tianshan uplift zone, Houxia graben, Nanshan uplift zone and piedmont depression successively. The strata are distributed in succession from old to new. The Tianshan uplift zone is mainly Paleozoic. The Houxia graben is mainly dominated by Mesozoic strata. The Nanshan uplift zone is composed mainly of Carboniferous tuff and tuffaceous siltstone. The piedmont depression is mainly composed of Quaternary alluvial and gravel. The digital elevation model（DEM）data used in this paper are derived from the ASTER GDEM elevation data with an initial resolution of 30 m × 30 m. Based on the analysis of SL and Hack profiles of river slopes in the mainstream of the Uramqi River Basin and its four major structural strata, this paper draws the following conclusions： （1） The whole Hack profile of the Urumqi River basin is on convex form and the balancing grade index K value is high （K = 531 ）, which shows that current structure in this basin is still active. （2） Analysis of 4 partitions in the Urumqi Riv

关 键 词：河长坡降指标SL Hack剖面 新构造 乌鲁木齐河 天山北麓 

分 类 号：P931.2[天文地球—自然地理学] P542