Geochemical features and their implication of provenances of riparian dunes in the northern China deserts

Rivers in deserts present unique geographical features owing to aeolian-fluvial interactions. In this study, 510 surface sediment samples were gathered from eight watersheds to systematically examine the major element characteristics of riparian sand dunes in northern China deserts. The findings revealed that these dunes could be categorized into three primary zones: Type I, comprising Keriya, Tora, Heihe, and Langqu rivers in the west; Type II, featuring the Maquan River in the Tibetan Plateau; and Type III, including Mu Bulag, Kuye, and Xar Moron rivers in the east. Specifically, the Type III region is characterized by a limited fresh material supply, a relatively high Chemical Index of Alteration (CIA), and the influence of nearby rivers on the provenance of riparian dunes, leading to a higher degree of chemical weathering than that of Type I in the west. Notably, Type II is marked by weak-moderate chemical weathering degree and a comparatively higher CIA value. These classifications and their difference of degree of chemical weathering are possibly governed by the type of parent rock and the availability of material. This research offers new insights into the classification of riparian dunes impacted by aeolian-fluvial interactions in arid regions of the northern China deserts. Furthermore, it provides valuable implications for studies focusing on the provenance of sediments.