格尔木河上游水成沉积物矿物元素时空变化、流域风化及其驱动机制

Temporal and spatial variations of mineral elements in hydrogenic sediments, basin weathering and its driving mechanism in the upper Golmud River

中文关键词:  格尔木河  矿物元素  区域风化  季风西风作用

英文关键词:Golmud River basin  Mineral element  Chemical weathering  Westerly action of monsoon

中文摘要:

      格尔木河流域中成盐矿物的风化迁移规律对察尔汗盐湖中盐类资源的补给具有重要意义。本文对格尔木河流域的纳赤台（NCT）和小干沟（XGG)剖面的形成年代、成盐元素变化规律进行了研究，并结合流域内上下游不同类型沉积物的元素特征进行对比分析，得出如下结论：（1）末次间冰期以来，格尔木河中游河谷沉积物中主要成盐矿物较上游西大滩、昆仑河小流域次级盆地中要高，表现出较为明显的富集状态。（2）流域上游湿冷山麓地带河谷沉积物的风化程度明显高于中游干热河谷，表明上游冰川融水、较充沛的降水条件和较好的水岩反应过程是主导流域风化的主要因素。物质在流域各个次级盆地间物质输送具有跳跃性、传递性和继承性。（3）流域内的风化过程与晚更新世以来的冰期-间冰期气候旋回和季风-西风相互作用密切相关，即暖湿阶段主要受季风控制，以化学风化为主；干冷阶段受西风控制，风化以物理风化为主。总之，格尔木河流域上游山麓地区元素的风化迁移和中游河谷沉积物对元素的继承转移是流域内物质流动的主要形式。

英文摘要:

      The weathering and migration rule of salt-forming minerals in Golmud River basin is of great significance to the replenishment of salt resources in Qarhan Salt Lake. In this paper, the formation ages and changes of salt-forming elements of Nachitai (NCT) and Xiaogangou (XGG) profiles in the Golmud River Basin were studied, and the element characteristics of different sediment types in the upper and lower reaches of the basin were compared and analyzed, and the following conclusions were drawn: (1) Since the last interglacial period, the main salt-forming minerals in the sediments of the middle Golmud River valley are higher than those in the upper Xidatan and Kunlun River sub-basins, showing obvious enrichment status. (2) The degree of weathering of the sediments in the wet and cold foothills of the upper reaches of the basin is significantly higher than that in the hot and dry valleys of the middle reaches, indicating that the meltwater of glaciers, more abundant precipitation conditions and better water-rock reaction process in the upper reaches are the main factors leading to the weathering of the basin. The material transport in each sub-basin has the characteristics of jump, transfer and inheritance. (3) Weathering processes in the basin were closely related to the glacial-interglacial climatic cycles and monsoon-westerly interactions since the late Pleistocene, that is the warm and wet stages were mainly controlled by seasonal risks and were dominated by chemical weathering. The dry and cold stage is subject to western risk control, and the weathering is mainly physical weathering. In conclusion, the weathering and migration of elements in the foothills of the upper reaches of Golmud River Basin and the inheritance and transfer of elements in the sediments of the middle reaches of Golmud River Basin are the main forms of material flow in the basin.