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选择位于青藏高原和云贵高原过渡区的泸沽湖作为研究对象,对南部主湖区70个表层沉积物样品进行了粒度分析,结合湖泊周围自然地理要素,探讨了粒度各组分在空间上的分布特征及其影响因素。结果表明:泸沽湖南部主湖区表层沉积物沉积类型以黏土质粉砂为主,少数样品为砂质粉砂、砂,砾石主要分布在研究区南部和北部湖滨带,其中粉砂是该研究区的优势粒级。另外,南部主湖区表层沉积物粒度各组分分布具有明显的空间差异性,其中研究区东南侧及西南侧由于受入湖河流(山跨河、三家村河)的影响,导致黏土组分呈舌状分别向北、向东北方向延伸,但东南侧由于受湖水外流形成的定向湖流顶托作用,对研究区物源的贡献较弱;研究区西北部砂组分由于受到悬移作用和定向湖流影响,由西北向东南方向凸出;由于受反时针环流作用的影响,大量细粒物质由研究区北部和西南侧悬移至研究区南部并沉积下来,使得此处有大量细物质沉积。同时指出,泸沽湖南湖表层沉积物粒度空间分布的差异性特征受控于湖泊沉积动力过程及沉积物对环境变化响应敏感程度的差异,研究湖泊表层沉积物粒度组成不仅对于认识湖泊水动力及物质输入状况有很大的促进作用,对合理选择钻孔岩芯位置、开展湖泊沉积古气候环境变化研究具有一定的参考意义。
Based on the selection of the Lugu Lake located in the transitional areas of the Qinghai-Tibet Plateau and the Yunnan-Guizhou Plateau, the grain size of 70 surface sediment samples in the southern main lake area was analyzed and the spatial distribution characteristics of each component of the grain size were discussed in combination with the natural geographical elements around the lake And its influencing factors. The results show that the sedimentary types of the sediments in the main lake are mainly clay clayey sediments in the south of Lugu Lake. A small number of samples are sandy silt. Sand and gravel are mainly distributed in the southern and northern lakeside of the study area. The advantage of grain size. In addition, there are obvious spatial differences in the distribution of the grain size of the surface sediments in the southern main lake. In the southeast and southwestern sides of the study area, due to the influence of the inflow rivers (mountain crossing and Sanjiazucun) But the contribution to the provenance of the study area is weaker due to the directional watercropping caused by the outflow of the lake in the southeast. Due to the effect of suspended sedimentation and orientation Due to the anti-clockwise circulation, a large amount of fine-grained material suspended from the northern and southwestern sides of the study area to the south of the study area and deposited, resulting in a large amount of fine-grained sediments . At the same time, it is pointed out that the difference characteristics of spatial distribution of surface sediments in South Lake in Lugu Lake is controlled by the dynamic process of lake sedimentation and the sensitivity of sediments to environmental changes. Studying the grain size composition of surface sediments in lake is not only helpful for understanding the hydrodynamic and matter Input conditions have a great role in promoting the rational choice of drilling core location, to carry out lake sedimentary paleoclimatic environmental changes research has some reference value.