察尔汗盐湖线形沙丘沙物质来源及输移路径

采用地球化学元素方法，探讨了察尔汗盐湖北岸线形沙丘的沙物质来源，并对区域物质输移路径进行了讨论。结果表明：戈壁、雅丹廊道流沙和线形沙丘的常量元素均以SiO₂、Al₂O₃和CaO为主，微量元素均以Cl、Ba、Sr和Co含量较高；线形沙丘与戈壁表层沉积物的常量与微量元素的UCC标准化值分布模式均较一致，且与距盐湖较近的雅丹廊道流沙也存在一定程度的相似性；沉积物的化学风化程度较弱，均处于早期的脱Na、Ca阶段，且在A-CN-K三角图中均位于大陆风化趋势线的反向延长线上，可能代表河流溶质的风化趋势。因此，戈壁表层沉积物和雅丹廊道流沙在线形沙丘形成过程中均可提供沙物质来源，且前者提供的沙物质应该更多。柴达木盆地可能为其下风向黄土的物质源区之一，但是提供的粉尘颗粒有限。

Provenance and Transport Pathways of Linear Dunes in the Northern Margin of Qarhan Salt Lake of China

By using geochemistry method, this paper investigates the sediment provenance and transport pathways of linear dunes in the northern margin of Qarhan Salt Lake. Major elements of gobi, sands in the yardang corridors and linear dunes are predominated by SiO₂, Al₂O₃, and CaO, while the higher content trace elements are Cl, Ba, Sr and Co. The linear dunes' UCC-normalized patterns of major and trace elements are in consistent with the gobi surface sediments, respectively; and with some similarity between the sands in the yardang corridors close to the salt lake. The chemical weathering degree of sediments in the study area is too weak, because they all in the early stage of losing Na and Ca. They all are located on the opposite direction of traditional continental weathering trend line in the A-CN-K ternary plot, which indicate they may represent the weathering trend of fluvial dissolved loads. Therefore, all the sediments in gobi and yardang corridors can transport sands to linear dunes, and the former may provide much more sands. The Qaidam Basin may be the provenance region of the downwind loess, with limited silt particles supply.