Abandonment of ancient cities near the Salawusu River valley, China, triggered by stream capture

Abstract

AbstractSeveral cities in the Salawusu River basin in the western Mu Su Desert of China were abandoned after the Yuan Dynasty (1271 to 1368 CE). Incisions of rivers caused by earth uplift coupled with a drier climate after the Yuan Dynasty have previously been attributed to such irreversible abandonments. Here we use geomorphological analyses, coupled with hydrological reconstructions to investigate the ancient stream patterns in the period leading up to the abandonments. We find that the abandonment of wells, the thermoluminescence age of which is about 640 years before present, in these cities coincided with a stream capture event that led to rapid river valley incision of up to 95 mm/year. We suggest that this stream piracy event lowered the water table in the area and triggered the abandonment of settlements, rather than a change to a drier climate as previously believed. We conclude that when considering environmental influences on archaeological records, geographic events must be considered in addition to climatic change.