Geomorphic changes along the Yiluo River influenced the emergence of the first urban center at the Erlitou Site, Central Plains of China

Geomorphological research at archaeological sites has shown that ancient environmental conditions have significant implications for understanding changes in archaeological site distribution and layout. The Luoyang Basin in Central China was a center for early urbanism including several large cities in antiquity, but the geomorphic environments that supported these ancient cities have remained uninvestigated. From 2006 to 2011, a field project was conducted in the Luoyang Basin in attempt to understand the relationship between environmental changes and the development of urbanism. Forty-nine profiles were sampled on the alluvial terraces of the Luoyang Basin to examine the geomorphological evolutionary history of the Yi River and Luo River. Our study indicates that the T1 Terrace formed around 7000 cal yr BP and provided a stable landform for Yangshao (7000-5000 yr BP) and Longshan (5000-3900 yr BP) settlements. However, massive floods around 4000-3800 yr BP destroyed some of these late Longshan settlements and caused the Luo River to change its course to southern part of the Luoyang Basin. Those floods significantly altered the landforms and laid a solid foundation for the succeeding development of the urban center at Erlitou.