Identification and provenance analysis of sediments’ end-members in the typical black soil area of northeast China

Introduction The Songnen Plain is a significant black soil region in China, where the sedimentary processes and provenance of sediments are crucial for reconstructing the regional environmental evolution. Methods In this study, end-member modeling analysis coupled with geochemical proxies of major and trace elements was applied to systematically investigate the grain-size distribution and sediment sources in the northwestern margin of the Songnen Plain. Paired samples from surface (0.2 m) and subsurface (1.0 m) layers across different geomorphic units were compared. Results Four to six distinct grain-size end members were identified, with their number and characteristics varying across geomorphic units. Discussion These include long-range aeolian dust (EM1), mid-range suspended aeolian material (EM2), mid-to short-range wind-sorted sand (EM3), fluvial suspended and channel deposits (EM4-5), and slope mud-flow deposits (EM6). Aeolian end-members (EM1-3) dominate both surface and subsurface sediments (>71%), whereas fluvial components (