SEISMOLOGY AND GEOLOGY ›› 2016, Vol. 38 ›› Issue (3): 560-581.DOI: 10.3969/j.issn.0253-4967.2016.03.005

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GEOMORPHIC FEATURES OF THE HEIHE RIVER DRAINAGE BASIN IN WESTERN QILIAN SHAN-HEXI CORRIDOR AND ITS TECTONIC IMPLICATIONS

SU Qi1, YUAN Dao-yang1,2, XIE Hong1,2   

  1. 1 Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China;
    2 Lanzhou National Observatory of Geophysics, Lanzhou 730000, China
  • Received:2015-06-02 Revised:2016-06-28 Online:2016-09-20 Published:2016-10-15

祁连山-河西走廊黑河流域地貌特征及其构造意义

苏琦1, 袁道阳1,2, 谢虹1,2   

  1. 1 中国地震局兰州地震研究所, 兰州 730000;
    2 兰州地球物理国家野外科学观测研究站, 兰州 730000
  • 通讯作者: 袁道阳,男,研究员,电话:0931-8276712,E-mail:daoyangy@163.com
  • 作者简介:苏琦,男,1990年生,2015年在中国地震局兰州地震研究所获构造地质学专业硕士学位,研究方向为活动构造与构造地貌,电话:18810715875,E-mail:xbdsq11@163.com。
  • 基金资助:

    中国地震局地震行业科研专项(201308012)与国家自然科学基金(41030317)共同资助

Abstract:

Using quantitative geomorphic factors for regional active tectonic evolution is becoming more and more popular. Qilian Mountains-Hexi Corridor which locates in the northern edge of Qinghai-Tibet plateau is the most leading edge of the plateau's northward extension. The uplift rate of all segments and the intensity of influence from tectonic activity are the important evidences to understand the uplift and extension of the plateau. Heihe River Basin is located at the northern piedmont of the western segment of Qilian Mountains, the development of the rivers is influenced by the tectonic activity of the Qilian Mountains, and the unique river morphology is important carriers of the regional tectonic uplift.
Geomorphologic indexes such as hypsometric integral, geomorphologic comentropy and river longitudinal profiles were extracted by GIS tools with free access to the Shuttle Radar Topography Mission(SRTM)DEMs, and according to the different expression of the geomorphological indexes in the Heihe River Basin, we divided the drainage basin into two parts and further compared them to each other.
Recent studies reveal that obvious differences exist in the landscape factors(hypsometric integral, geomorphology entropy and river profiles)in the east and west part of the Heihe Basin. The structural intensity of the west part is stronger than that of the east, for example, in areas above the main planation surface on the western part, the average HI value is 0.337 8, and on the eastern part the HI value is 0.355. Accordingly, areas under the main planation surface are just on the contrary, indicating different structural strength on both sides. Similar phenomenon exists in the whole drainage basins. Furthermore, by comparing the fitting river profiles with the real river profiles, differential uplift is derived, which indicates a difference between west and east(with 754m on the western part and 219m on the east). Comprehensive comparison and analysis show that the lithologic factors and precipitation conditions are less influencing on the geomorphic factors of the study area, and the tectonic activities, indicated by field investigation and GPS inversion, are the most important element for geomorphic evolution and development. The variation of the geomorphologic indexes indicates different tectonic strength derived from regional structures of the Qilian Shan.

Key words: the western region of the Qilian Mountains, DEM, Heihe drainage, geomorphology, tectonic activity

摘要:

采用定量化的地貌因子研究区域构造活动及其演化已成为构造地貌学的一种常用手段。祁连山-河西走廊位于青藏高原东北部边缘,是高原向NE方向挤压扩展的前缘部位,该区河流水系的地貌发育过程记录了高原隆升与挤压扩展及其气候环境效应的重要信息。位于祁连山北部山前的黑河流域向N穿过河西走廊和北山地区,其河流地貌的发育与祁连山的构造隆升直接相关。基于诸多地貌因子(面积-高程积分、地貌信息熵以及河流纵剖面)的研究结果均显示黑河流域所涉及的祁连山东、西段的构造活动存在明显差异,具有西强东弱的特点,如西段流域的平均面积高程积分值(HI)为0.541而东段仅为0.466 1;并且根据河流纵剖面分析得到的差异隆升值西段为754m,也远高于东段的219m;而降雨等气候因素则存在东强西弱的特点。综合对比分析发现,本区岩性与降水条件等对研究区地貌因子的影响有限;构造活动是地貌演化发育的主控因素,控制着该区现今的构造变形、地貌发育及其演化历史。

关键词: 祁连山西段, DEM, 黑河流域, 地貌, 构造活动

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