Liu Jiale, Zhang Changmin, Zhang Xianghui, Zhu Rui, Shaohua Zhao
Yangtze University College of Earth Sciences, Wuhan, 430100, China.
Sci Rep. 2024 Sep 12;14(1):21329. doi: 10.1038/s41598-024-72102-x.
The characteristics of fan sediment in the distributive fluvial system are evaluated based on a thorough analysis of modern silt in the Guertu river distributive fluvial system, as well as data obtained from UAV aerial photography and satellite remote sensing. The Guertu River Distributive Fluvial System (DFS) is classified into three stages, namely "proximal," "middle," and "distal," based on the examination of river morphology, sediment variations, sedimentary attributes, and other relevant aspects throughout different sections of its tributaries, from the source to the mouth. At the upstream section of the downstream fining sequence, the slope is the steepest and the hydrodynamic conditions are intense, resulting in the formation of a predominantly big gravel braided river. The river bed section has a morphology resembling a combination of a "V" and a "U" shape. It is characterized by a narrow and deep configuration, with a relatively short breadth. The sediment primarily consists of medium to large-sized gravel with minimal sand content. The gravel exhibits good roundness and displays a considerable degree of orientation. The primary microfacies present are braided channel and flood plain. The slope of the central area is decreased in comparison to the nearby end, primarily due to the presence of extensive braided rivers. The river bed has a greater width, with minor eolian dunes visible in the river channel. The gravel particles are predominantly fine to medium in size, and there is an increased amount of sand present. The predominant microfacies are braided channels, floodplains, and eolian dunes. At the distal end, the slope is minimal, the landscape is level, the braided river transitions into a meandering river, the sediment consists primarily of sand, and the signs of bioturbation are clearly visible. The primary microfacies consist of braided channels, meandering channels, floodplains, eolian dunes, lakes, and swamps.
基于对格尔图河分流河道系统现代粉砂的全面分析以及无人机航空摄影和卫星遥感获取的数据，对分流河道系统中的扇状沉积物特征进行了评估。通过对格尔图河分流河道系统（DFS）各支流从源头到河口不同断面的河流形态、沉积物变化、沉积属性及其他相关方面的考察，将其分为三个阶段，即“近端”、“中段”和“远端”。在下游变细序列的上游段，坡度最陡，水动力条件强烈，形成以大砾石为主的辫状河。河床断面形态类似“V”形和“U”形的组合。其特点是狭窄且深，宽度相对较短。沉积物主要由中大型砾石组成，砂含量极少。砾石圆润度好，具有相当程度的定向性。主要微相为辫状河道和泛滥平原。与附近末端相比，中心区域坡度减小，主要是由于存在大量辫状河。河床宽度更大，河道中可见少量风成沙丘。砾石颗粒主要为细到中等大小，砂含量增加。主要微相为辫状河道、泛滥平原和风成沙丘。在远端，坡度最小，地形平坦，辫状河转变为曲流河，沉积物主要由砂组成，生物扰动迹象明显可见。主要微相包括辫状河道、曲流河道、泛滥平原、风成沙丘、湖泊和沼泽。
