Geochemical compositions of the Onqin Daga Sand Land and Horqin Sand Land and their implications for weathering, sedimentation and provenance

Sand and fine sand fractions (＜10 μm and＜63 μm) collected from the Onqin Daga Sand Land and the Horqin Sandy Land are analyzed for geochemical elements including major elements, trace elements, rare earth elements and Sr-Nd isotopes, in order to evaluate the chemical weathering, sedimentary characteristics, source areas, and the contribution of the Xar Moron River to the mass exchange between the two sands. The sediments are characterized by such features as low CIA, PIA and CIW values, high WIP and ICV values, low Zr/Sc ratio, A-CN-K and MFW diagram suggesting that the sediments are in the early stage of chemical weathering and low in maturity, and only experienced a simple process of sedimentary recycling. The provenance discrimination diagram shows that the parent rocks of Onqin Daga Sand and Horqin Sandy Land are dominated by intermediate-acid granitic rocks and have a mixed source from the western part of the Great Hinggan Mountains and the northern part of the North China Craton. In addition, the fine components, especially the component＜10 μm, are very similar in geochemical composition for the two sandy areas, and it is believed that fine grain matters may have been transported from the Onqin Daga Sand Land to the Horqin Sand Land taking the Xar Moron River as a bridge. At the same time, atmospheric dust transport under prevailing winds may also play a certain role in fine sediment transportation.