文章选择了晋陕峡谷北段的保德府谷地区作为研究区域。通过对区域内黄河高阶地18个地点沉积物特征的观察和9个剖面的详细描述，以及21个砾石样品成分和形态特征的统计分析，揭示出研究区域内基岩面呈宽谷形态；基岩面上存在河流相砾石层，该砾石层成分较复杂，磨圆度好，ab面倾向主体指向北，是古河流存在的证据；有的地区砾石层之上为湖相沉积，总体呈透镜体状；湖相层和砾石层之上的三趾马红土底部和下部含有洪积相的砾石透镜体和略微倾斜的钙板层，其中的砾石成分相对简单，磨圆度也差；研究区域内沉积序列缺失午城黄土和离石黄土的下部。基于上述沉积物的特征和分布可以得出结论：保德府谷地区在中新世保德红土堆积之前就存在南北向的河流，应为古黄河。在现代晋陕峡谷区，地貌经历了宽阔的古黄河－古黄河河谷洼地积水成湖，湖泊突然干涸－保德红土堆积－长期弱侵蚀－峡谷下切与黄土堆积的演化过程。而且红土堆积过程中，当地存在一定的起伏，以红土的缓慢堆积与微弱侵蚀为特点。古黄河积水成湖可能与鄂尔多斯周缘地区的新构造运动有关，晋陕峡谷的形成则与鄂尔多斯整体抬升、黄河快速下切相关。

This study focuses on the Baode-Fugu region at the north part of Jinshan Gorges and the fluvial sediments were observed at eighteen sites and 9 sections were described in details. The gravels of 21 samples were analyzed with statistical analysis of their components and morphological features. The results show that an open bedrock valley is located high above the modern Yellow River Gorges. The fluvial gravel layers sitting on the bedrock surface is an evidence of the once existence of an ancient river. The lacustrine deposits can be found at the top of gravel layers in some places which build up a big lens under the red clay layers. The red clay in this area is characterized with Hipprion fauna and is identified belong to the Miocene and Pliocene. At the bottom and lower part of the red clay, there are some big lenses of angular gravels. The general features of it are layers of hard calcific concretions inter-bedded with red clay layers. Both the calcic horizons and clay layers are tilted at some locations which indicate a gentle relief of the ancient landforms during their formation. Between the red clay and the overlying loess, there is an erosional surface and the Wucheng loess and lower part of Lishi loess are lacked in this area. Based on the observations and analyses, it can be concluded that a river running north to south existed before the Miocene red clay in Baode-Fugu area, which should be the ancient Yellow River. In the modern Jinshan Gorges, the landform has experienced a history of the ancient Yellow River – an ancient lake and its disappearance – the slow accumulation of red clay and a longtime week erosion – the down-cutting of the valley and loess deposition. The formations of lake from the ancient Yellow River might be related to the neotectonic movement of the marginal areas around the Erdos Plateau, while at the same time, the formation of the Jinshan Gorges might be related to the whole uplift of the Erdos and the rapid undercutting of the Yellow River.