利用面积高程积分方法研究龙门山断裂带地貌隆升特征

为对龙门山断裂带区域的构造与侵蚀现状进行分析,通过利用ArcG IS对龙门山断裂带内的ASTER-DEM30 m数据进行面积-高程积分计算,并结合构造、岩性、第四系以及河流等基础资料研究了该地区隆升差异。结果表明:面积-高程积分值(hypsometric integral,HI)0. 43区域主要集中在研究区的西部及北部同时,其值与区域内的夷平面具有较好的耦合性;HI 0. 60在松潘—甘孜褶皱带内的分布较广,在扬子地台分布范围最少,龙门山构造带无分布; HI 0. 35分布主要沿着龙门山构造带为中心进行展布,以侵蚀下切为主。在构造带较为活跃的区域,构造活动依然是区域作用的主要背景,在内动力直接作用的区域内,HI0. 43,以隆升为主;河流、岩性分布特征以及构造断裂的密度会随着后期作用逐渐对抬升起到抑制作用,断裂带发育密集、第四系分布较广以及岩性复杂的龙门山构造带,HI 0. 35,是以侵蚀下切为主;扬子地台河流发育密集且发育程度高,HI偏低,以隆升停滞或侵蚀为主。可见,构造、岩性、第四系以及断裂带的分布对区域地貌特征影响较为明显,而局部区域上的差异是由影响因素发挥作用差异决定的。根据值,为避免工程选址处于构造活动强烈区域提供一定依据。

Study on the Geomorphic Uplift Characteristics of the Longmenshan Fault Zone Using Hypsometric Integral Method

In order to analyze the tectonic and erosion status of the Longmenshan fault zone, the area-elevation integral calculation was performed on the ASTER-DEM30m data in the Longmenshan fault zone by using ArcGIS, combined with structure, lithology, Quaternary and rivers. Basic data was used to investigate the ups and downs in the region. The results showed that the HI>0.43 area was mainly concentrated in the western and northern parts of the study area, and its value had good coupling with the plane in the area; HI>0.60 was widely distributed in the Songpan-Ganzi fold belt, in the Yangtze area. The distribution of the platform was the least, and the Longmenshan tectonic belt had no distribution; the distribution of HI<0.35 was mainly distributed along the Longmenshan tectonic belt, and the erosion was mainly cut. In areas where the tectonic belt was more active, tectonic activity was still the main background of regional action. In the region where the internal dynamics directly acts, HI>0.43, mainly uplifting; the distribution characteristics of rivers, lithology and tectonic faults would follow the late action gradually inhibited the uplift, the fault zone was densely developed, the Quaternary was widely distributed, and the lithology was complex. The Longmenshan tectonic belt, HI<0.35, was mainly the erosion undercut; the Yangtze platform was densely developed. The degree of development was high, and the HI value was low, mainly due to stagnation or erosion. It is concluded that the distribution of tectonic, lithologic, quaternary and fault zones had a significant impact on regional geomorphological features, while the difference in localized regions was determined by the difference in the effects of influencing factors. According to the HI value, it was necessary to provide a basis for avoiding the location of the project in a strong area of tectonic activity.