Geochemical and isotopic characteristics of sediments for the Hulun Buir Sandy Land, northeast China: implication for weathering, recycling and dust provenance

Fluvial, lacustrine and aeolian sediments in the Hulun Buir Sandy Land (HBSL), northeast China are investigated for the first time to be a key supplementation of the Asian aeolian dust system. Fine-grained components (< 10 mu m, < 30 mu m and < 63 mu m) were separated for elemental and isotopic analyses. Major and trace elements, Rare Earth Elements (REE) and Sr-Nd isotopic compositions were employed to evaluate their source-area chemical weathering, sediment recycling and source-rock composition, and to infer their contribution to aeolian deposits to the proximal Northeast China Plain (NCP) and the distant regions such as the Japan Sea. Low chemical index of alteration (CIA) and high weathering index (WIP) indicate that the sediments in the HBSL were characterized by weak chemical weathering and moderate sedimentary recycling. Volcanic ash components were detected in these sediments, implying that the parent rocks are dominated by felsic with minor contribution of intermediate igneous rocks. These sediments were originated from the weathering-eroding products of the Great Xing'an Range terrane via fluvial process. Based on multiple tracers such as the ratio of immobile elements, REE and Sr-Nd isotopic compositions, and the vegetation, geomorphic and meteorological features, it is suggested that the sediments in the HBSL have limited contribution to the aeolian deposits in the eastern and central NCP, as well as further-away areas such as the Japan Sea.