The depositional Environment at Shuidonggou Locality 2 in Northwest China at -72-18 kaBP

Shuidonggou site has abundant Paleolithic remains of Late Pleistocene deposition. Studying the evolution of depositional environments is essential to the comprehensive understanding of the living conditions of ancient populations. To reconstruct the depositional environment at Shuidonggou, we carried out archaeological excavations and collected systematic deposition samples at the key position of Shuidonggou Locality 2 for grain size analysis and sporopollen statistics. The environmental evolution around the Shuidonggou site generally underwent four stages at ~72-18 kaBP. During the first stage （~72-41 kaBP）, the river developed with gravel and sand stratums. During the second stage （41-34 kaBP）, a swamp with numerous aquatic plants formed. In the third stage （34-29 kaBP）, site formation was characterized by shallow lake depositional conditions; the climate was relatively warm and humid. The marginal bank depositional conditions deteriorated during the fourth stage （29-18 kaBP）, and the site underwent several dry events; the climate also became drier and colder.