Fluvial-aeolian interactions in northern China (Upper Yellow River): Implications for provenance and paleoenvironmental interpretations

Abstract

Investigating fluvial-aeolian interactions is important for understanding Earth surface processes in arid regions. In this study, we conducted detailed grain size, geochemical, and heavy-mineral analyses of the 21.25-m-long HDZ core to determine the provenance of Holocene aeolian deposits in Inner Mongolia and their relationships with the Yellow River and surrounding desert areas. Significant differences in grain-size parameters and concentration of geochemical elements with stratigraphic depth were highlighted. Compositional data and heavy-mineral assemblages indicate that aeolian sediments blown into the Yellow River channel were largely derived from the Ulan Buh Desert or Kubq Desert and supplied by the Ten Tributaries during the rainy season. Chemical indices depicta particularly low weathering intensity during the late Holocene between 3.3 and 1.0 ka, when the dry-cool climate led to desert expansion in the Inner Mongolia region of the Yellow River. Starting from ∼2000 BP during the Han Dinasty, large-scale immigration, extensive agricultural activities, and intensified animal grazing compromised the stability of surface soil, leading to desertification and enhanced aeolian-sand transport across the Inner Mongolia region. Our research helps understand the extreme sensitivity of vulnerable dry environments to climate change at different time scales and provide a reference for provenance identificationin a region of extensive fluvial-aeolian interactions.