Origin and provenance of Red Clay in north Hunan Province, China: Inferred from grain-size analysis and end-member modelling

A number of open-air Paleolithic sites have been found and excavated in South China, and are characterized by Red Clay deposits. A detailed knowledge of the Red Clays is crucial for better understanding the archaeological significance of the sites and the paleoenvironments during hominin occupation. However, the origin and provenance of the Red Clays is debatable. Here, three sediment sequences from two Paleolithic sites (Wuyashan and Sandinggai) on fluvial terraces in north Hunan Province, China, were investigated using grain-size analysis and end-member modeling. The spatial distribution and grain-size characteristics of the Red Clays reveal their aeolian origin. The end-member modeling demonstrates that the Red Clays consist of two end-members (EM1 and EM2 with mode sizes of 5.6 and 11.2 mu m, respectively). The south-eastward-fining trend indicates that the EM1 component (fine dust) was transported from North China. We deduce that the EM2 component (coarse dust) is mainly from the nearby desiccated fluvial systems of the Yangtze River. The change in grain size with depth in the Red Clay sections may be caused by chemical weathering. The aeolian origin of the Red Clays may imply that the highlands occupied by hominins in the study region were not inundated with floods.

Automated summary

The research reveals that the Red Clays have aeolian origins. End-member modeling shows that the Red Clays consist of two components (EM1 and EM2 with mode sizes of 5.6 and 11.2 mu m, respectively). The south-eastward-fining trend suggests that the EM1 component (fine dust) was transported from North China, while the EM2 component (coarse dust) is mainly from the nearby desiccated fluvial systems of the Yangtze River.