Abstract: The Salawusu Valley is located in a zone between the Loess Plateau and the Ordos Desert, and it is an important part of the desertloess ecotone in north China and is very sensitive to climatic and environmental changes. In this study, the Dishaogouwan profile, a typical sedimentary sequence in the Salawusu Valley, was chosen as the study area to investigate the isotopic profiles and try to reveal the variation of sediment sources in the desertloess ecotone. The results are as follows: ① Coarse eolian deposits (>75 μm) came from wind erosion of the highlands in the centralwestern Ordos, and coarse fluviallacustrine deposits originated mainly from water erosion of underlying eolian deposits; ② Fine eolian deposits (<75 μm) with absolute  [WTBX]ΔεNd(0)[WTBZ] values ≤1 originated basically from the wind erosion of the highlands in centralwestern Ordos and the refining of coarse particles in situ, but fine eolian deposits with absolute   [WTBX]ΔεNd(0)[WTBZ] values ＞1 came from more complex sources; ③ Fluviallacustrine fine deposits of the Chengchuan and middlelower Salawusu formations came from water erosion in the central Loess Plateau, but the deposits of the upper Salawusu formation were significantly disturbed by eolian fine particles from the centraleastern Ordos Desert. This study is very helpful for understanding the evolution of the desertloess ecotone in north China.

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