Four natural sedimentary profiles (with a length of approximately 4.5 m and an age of around 10.0 kaBP) were selected in the vicinity of the southern section of the western city wall of Zhongdu of the Jin Dynasty, the earliest capital of Beijing. Sediment optically stimulated luminescence (OSL) dating, accelerator mass spectrometry (AMS) ¹⁴C dating and grain size analysis were conducted on the profiles. The results show that the sedimentary facies in this area can be divided into three hierarchical levels: the first-order alluvial plain facies, the second-order riverbed subfacies and floodplain subfacies, as well as six types of third-order microfacies including riverbed, distributary channels, point bars, floodplains, flooded lands and low-lying lands. The geomorphic evolution of the area is divided into the following stages: the development stage of the ancient Leishui River before approximately 7.0 kaBP, the branching channel development stage within the paleochannel from 7.0 to 6.0 kaBP, point bars and river floodplains development stage from 6.0 to 4.5 kaBP, and the flooded land and low-lying land development stage from 4.5 to 2.5 kaBP. A sand lens with an age of about 0.9 kaBP is present in the central part of the area, which is inferred to be the sediment of the moat of Zhongdu of the Jin Dynasty.

选取北京建都之始的金中都西城墙南段附近4个自然剖面(长度约为4.5 m, 年龄约为10.0 kaBP), 进行沉积物光释光(OSL)测年、AMS14 C测年和沉积物粒度分析。结果表明, 该区域的沉积相可分为一级冲积平原相、二级河床亚相和河漫亚相以及河床、分支河道、边滩、河漫滩、泛滥滩地和低洼地6个三级微相; 地貌演化分为以下几个阶段: 约7.0 kaBP以前为古㶟水发育阶段, 7.0~6.0 kaBP为故道中分支河道发育阶段, 6.0~4.5 kaBP为边滩和河漫滩发育阶段, 4.5~2.5 kaBP为泛滥滩地和低洼地发育阶段。该区域中部有约0.9 kaBP的砂层透镜体, 推测为金中都护城河沉积。