As one of the most massive accumulations of loess in the world, the Chinese Loess Plateau (CLP) has become one of the key areas to study Quaternary environmental changes. The Mangshan (MS) loess section (34°58′N, 113°22'E) locates in the southeast corner of CLP adjacent to the vast North China Flood Plain and downstream to the Sanmen Gorge,which had been the last barrier for the Yellow River to flow eastward into the sea,leading to be a critical area for understanding the evolution of the Yellow River. The physical features of the MS loess such as extremely thickness, exceptionally high accumulation rates, lower magnetic susceptibility, and coarser grain-size,show close correlation to the regional environmental changes, particularly via the comparison with other typical sections of arid Luochuan (LC) and Baishui (BS) loess in the CLP,and humid Huainan (HN) loess south to the CLP. Due to its contrast features and critical location, it has attracted study on magnetostratigraphy, sedimentology and luminescence chronology, etc. of the MS loess. Our research finds the new evidences of the headward erosion,happened around 200ka between the Sanmen Basin and the Gorge,led to the provenance change of the MS loess,and the dramatic increases of the sediment flux along the river. This paper respectively correlates the MS loess to other typical loess sections, the MS loess to the fluvial deposits along or upstream of the gorge, the upper (L_1~L_2) section, and lower (L_3~L_5) section of the MS loess,focusing on major element geochemical characteristics, which bear the information about climate change and dust sources and can provide the insight into the evolutionary history in the Sanmen Gorge area of the Yellow River. Our results present: (1) Compared with the LC loess, the MS loess shows substantial differences in the relatively active elements (e. g. Na20) and the relatively invariant elements (e.g SiO_2,Al_2O_3, and TiO_2); (2) Compared with the SM,LC,BS and HN loess, the MS loess with lower weathering intensity based on the CIA value and the A-CN-K plots reflects the source difference to the typical loess deposits in the CLP; (3) The MS loess with a higher Si02/Al_2O_3,SiO_2/TiO_2,and TiO_2/Al_2O_3 reflects a coarser grain-size and more quartz content. All of analyses indicate that the MS loess were derived from nearby area. Furthermore, UCC normalized graphs show that: (1) Compared with the LC loess, higher SiO_2 and lower Al_2O_3 in the MS loess are consistent with that of the fluvial sediments; (2) The upper MS loess sections (L_1 ~L_2) characterized by exceptional thickness show a lower weathering intensity and a higher Si02/Ti02 compared with the lower sections (L_3 ~L_5); (3) The MS loess kept similar pace with the fluvial sediments in the major element changes before and after S_2. Results suggest that the MS loess probably were derived the fluvial sediments upstream of the MS and sudden change of sediment supply happened in S2. The transition in S2 can be witnessed via dramatic increase of sediment supply and excessive deposition of the alluvial fan induced by basins connection via headward erosion along the Sanmen Gorge. Such excessive deposit compensation provided an extra source for the loess accumulation in the MS area.