Landform basis for the rise of early cities：A case from the upper Jialu River basin in Central China

As a significant emblem of human civilization, the emergence and development of early cities represents a pivotal milestone in the chronicles of human history. However, the environmental mechanisms underlying the rise of early cities are still ambiguous.  In this study, we have selected the upper Jialu River basin in Central China as our research area, which holds significance for the origin and development of Chinese civilization, with a multitude of Neolithic-Bronze city sites dispersed throughout. Using comprehensive field surveys, OSL dating, and grain size analysis, we have reconstructed the river's geomorphic evolution since the late Pleistocene. The influence of landforms on the intensive distribution of early city sites was also discussed. The results showed that the Jialu and its tributaries had been established during the early Pleistocene. At 80-16 ka BP, there was continuous accumulation in the area. From 15-9.8 ka BP, the river incision resulted in the formation of the expansive T3 terrace. Between 9.8-4 ka BP, the regional geomorphology stabilized. After 4 ka BP, tectonic uplift and subsidence resulted in the formation of the T2 terrace. After a minor accumulation, the T1 terrace was formed during the late historical period. The unique trough-shaped landform in the region played a pivotal role in the origin and development of early cities. The landscape stability resulting from the river incision facilitated early urbanization and the expansion of urban areas. The river incision also fixed river channels in the plain areas, which were previously occupied by swamps and wetlands that gradually transformed into land, providing a foundation for the establishment of Zhengzhou Shang City, the capital of the early Shang Dynasty.