苏干湖盆地周缘分支河流体系的几何形态及影响因素分析  

Geometry and control factors of distributive fluvial system around the Sugan Lake basin

作　　者：张祥辉 张昌民[1] 冯文杰[1] 朱锐[1] 陈哲[1] 赵康 张宝进 ZHANG Xianghui;ZHANG Changmin;FENG Wenjie;ZHU Rui;CHEN Zhe;ZHAO Kang;ZHANG Baojin(School of Geosciences,Yangtze University,Wuhan,430100)

机构地区：[1]长江大学地球科学学院

出　　处：《地质学报》2019年第11期2947-2959,共13页Acta Geologica Sinica

基　　金：国家自然科学基金项目（编号41772094）;国家科技重大专项（编号2016ZX05027-002-007）联合资助成果

摘　　要：本文利用Google Earth、Global Mapper等地理信息软件和雷达数字高程数据对苏干湖盆地周缘发育的分支河流体系(Distributive Fluvial System,简称DFS)进行研究。统计了苏干湖盆地周缘DFS的坡度、扇体半径、汇水盆地面积和周长、DFS面积和周长等数据。结果表明:苏干湖盆地发育的DFS在径向剖面上表现为下凹状,横剖面上表现为上凸状,DFS上发育的河道沿顶点处往下呈现为放射状;各几何形态参数相关性分析显示扇体面积与半径表现为强的正相关,与源区面积也表现为正相关,与坡度则表现为负相关;在盆地不同部位发育的DFS其几何形态参数以及河道样式存在明显的差异,这些差异主要与DFS所处的构造位置、母岩性质、水文条件等因素有关。构造活动的强烈程度与DFS源区大小及扇体形态呈正相关性,构造活动越强烈,其扇体几何形态变化越大。母岩性质对DFS的影响主要表现在物源供给上,地表疏松、抗侵蚀风化能力差的母岩区域,DFS的沉积物供给充足,DFS半径延伸较远,扇面积也较大;水文条件通过控制不同区域水动力大小影响DFS的发育,水动力较强的区域DFS的发育规模较大。Distributive fluvial system developed around the Sugan Lake Basin was studied by using geographic information software such as Google Earth, Global Mapper and digital elevation model(DEM). The gradient, fan radius, draining basin area and perimeter, the area and perimeter of DFSs around the Sugan Lake Basin were analyzed. The results demonstrate that the DFSs developed around the margin of the Sugan Lake Basin is concave in the radial section and convex in the cross section. The channels developed on DFSs are radial distributed downstream along the apex. Correlation analysis of geometric parameters shows that the fan area is positively related the radius, and positively correlated with the source area, but negatively correlated with the slope. There are significant variations in the radius, gradient, area, draining basin area and channel pattern of different DFSs developed in different parts of the basin margin. These differences are mainly related to the tectonic settings of DFS, lithology of source rock, and hydrological conditions. The influence of tectonic setting on DFS is mainly reflected in the area of the draining basin and the slope of DFSs. The higher intensity of the tectonic activity, the greater the change of DFS geometry. The influence of source rock lithology on DFS is mainly manifested in the sediment flux, the draining basin with loose and erodibility source rock could supply more sediment for the growth of DFSs and deposit larger DFSs. Hydrological conditions play an important role during the sedimentary process of DFSs, rainwater is the elementary source of water in the draining basin, and the snowmelt water from a fraction of mountains offer an extreme hydrodynamic for the associated draining basins. A draining basin with snowmelt water fed larger DFSs.

关 键 词：分支河流体系 几何形态 影响因素 陆相盆地沉积体系 河流沉积学 苏干湖盆地 

分 类 号：R73[医药卫生—肿瘤]