Landform basis for the rise of early cities in the upper Jialu river basin, central China

As a significant emblem of human culture, the emergence and evolution of early cities represent 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 conducted a comprehensive investigation of early cities and their landform basis in the upper Jialu River basin of Central China. By field surveys, OSL dating, and grain size analysis, we reconstructed the fluvial geomorphic evolution since the late Pleistocene and examined how landforms influenced the distribution of early city sites. The results showed that the water system pattern, including the Jialu River and its tributaries, had been established during the early Pleistocene. At 80-16 ka BP, there was continuous accumulation in the area. From 15 to 9.8 ka BP, the river incision resulted in the formation of the expansive T3 terrace. Between 9.8 and 2.5 ka BP, the regional geomorphology stabilized. Around 2.5 ka BP, river downcutting resulted in the formation of the T2 terrace. Following a minor accumulation phase, the T1 terrace emerged during the late historical period. The region's distinctive through-shaped landform was instrumental in the emergence and evolution 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.