柴达木盆地那棱格勒河流域表层沉积物微量元素组成及其对流域内锂的物源制约意义

Trace Element Geochemistry and Constrain on Lithium Provenance of River Sediments in the Nalinggele River Catchment of Qaidam Basin

中文关键词:  那棱格勒河流域  微量元素  卤水锂矿  物源属性  源岩风化作用

英文关键词:The Nalinggele river catchment  Trace elements  Li-rich brine  Provenance  Weathering process

中文摘要:

      柴达木盆地那棱格勒河流域是我国目前最大的盐湖型锂矿区和工业设施最为完备的卤水锂工业基地,长期以来关于其尾闾盐湖区锂的物源问题备受关注。尽管目前的众多研究已经对流域内地表水体及尾闾区盐湖中锂的物源有了较为一致的看法,但盆地周缘围岩风化在其中起到的作用仍缺乏系统性认识。基于部分保守性微量元素在物源示踪研究中的重要作用,通过对流域内河流表层沉积物中的REEY、Li、Sc、Co、Nb、Ta、Th等微量元素开展其地球化学行为方面的分析,探讨了沉积物的物源属性特征及其中锂元素的主要来源,为深入认识盐湖区可溶态锂资源的物源来源提供了新的证据。结果表明,那棱格勒河流域与毗邻的东、西对比区河流沉积物有着相似的化学风化背景和基岩类型,源岩均具有显著的长英质岩和基性岩的二元混合特征,且基性源岩所占比重更大；除尾闾盐湖区表层沉积物中的锂明显受到富锂孔隙水体夹带的影响外,其它地区锂的来源特征与沉积物的物源特征相同,表明地表迁移过程对沉积物中锂的通量影响较弱,沉积物中的锂更多是以赋存在相关矿物结构中的形式存在；研究区来自源岩风化作用提供的可溶态锂的量较为有限,尾闾盐湖中的锂资源主要以昆仑山深大断裂带涌出的富锂热泉水的长年补给为主。

英文摘要:

      The Nalinggele River Catchment in Qaidam Basin is the largest Li-rich brine mining area and the industrial base with complete industrial facilities in China.The matter source of lithium in its salt lake region has attracted much attention for a long time.Although many current studies have reached a relatively consistent view on the source of lithium in the study area,there is still a lack of systematic understanding for the role of the surrounding rock weathering process.Based on the characteristics of some conservative trace elements in tracing research,through analyzing the geochemical behavior of trace elements such as REE,Li,Sc,Co,Nb,Ta and Th in river surface sediments in the catchment, the provenance characteristics of river sediments and the lithium in those sediments were discussed.It provides new evidence for further understanding the provenance of dissolved lithium in the study area.The results show that the river sediments of Nalinggele River catchment and the adjacent east and west areas have similar chemical weathering background and bedrock types.The source rocks have significant binary mixing characteristics of felsic rocks and basic rocks,and the proportion of basic source rocks is larger.The source of lithium in sediments are the same as those of sediments,indicating that the surface migration process has a weak impact on the flux of lithium in sediments,and lithium in sediments mostly exists in the mineral structures.The amount of dissolved lithium provided by the weathering of source rocks in the study area is relatively limited.The lithium resources of salt lakes are mainly supplied by the hot spring water gushing from the deep fault zone of Kunlun Mountain for a long time.