季风边缘区湖泊表层沉积物粒度组分分布特征与影响因素  

Within-lake distributions of grain-size components and environmental implications based on the survey of lake surface sediment of Chinese monsoon marginal area

作　　者：郭晓阳[1,2] 王维[1,2] 王国良[1,2] 刘立娜[1,2] 马玉贞[3,4] 何江[1,2] 

机构地区：[1]内蒙古大学环境与资源学院,呼和浩特010021 [2]内蒙古大学环境地质研究所,呼和浩特010021 [3]北京师范大学环境演变与自然灾害教育部重点实验室,北京100875 [4]北京师范大学地表过程与资源生态国家重点实验室,北京100875

出　　处：《地理研究》2016年第4期677-691,共15页Geographical Research

基　　金：国家自然科学基金项目(41562009;41162004;41271207);内蒙古教育厅高等学校青年科技英才计划(NJYT-14-A01)

摘　　要：对内蒙古等地68个湖库共139个表层沉积物样品的粒度组分分布及其影响因子进行研究,探讨湖泊沉积物粒度分布特征及其成因机制和粒度组分的环境指示意义。结果表明：湖泊表层沉积物粒度可分为C1~C6共6个组分（0.4~1.9μm、2.0~12.0μm、17.0~58.0μm、70.0~150.0μm、170.0~500.0μm和〉600.0μm）,近湖心样品粒度组分以C1、C2、C3为主,过渡带样品以C3和C4为主,近湖滨样品以C5主导。受入湖河流影响的样点处水动力条件决定了粒度组分的空间分布,波浪作用造成的二次悬移再沉积可能造成了C3组分向湖心迁移并导致近岸C5组分富集。C1及C2组分中径流输入不容忽视,C3组分中风力悬移搬运贡献较大。C4、C5和C6含量可指示样点距河口的相对位置,C3可反映样点距岸相对位置。In this paper, within- lake grain- size components distribution was disclosed and its relationship to the controlling and influencing environmental factors were explored, to present bases for interpretation of core grain- size data. Specifically, 139 lake surface sediments were achieved from 68 lakes and reservoirs in the Inner Mongolia Autonomous Region, Gansu Province and Ningxia Hui Autonomous Region. The grain- size of surface sediments was measured using Microtrac S3500 particle size analyzer, and the grain- size components were fitted and partitioned using lognormal distribution function. Correlation analysis and ordination analysis including detrended component analysis（DCA） and redundancy analysis（RDA） were used to analyze the relationships between grain- size components distribution and influencing factors, including water depth（De）, the distance to shoreline（Ds）, the distance to river mouth（Dr）, the ratio between the distance to shoreline and the lake’s radius（Ds/R）, and the ratio between the lake’s radius and the distance to river mouth（R/Dr）. These factors can reflect the re-suspension caused by wave action（De）, the transport of shoreline clastic deposit（Ds and Ds/R）, the riverine clastic deposition and erosion process（Dr）, and the overall influence of riverine clastic deposition under specific hydraulic conditions（R/Dr）. Thus, the fitting and partitioning yields six components（i.e., C1： 0.4-1.9, C2： 2.0-12.0, C3： 17.0-58.0, C4： 70.0-150.0, C5： 170.0-500.0 and C6： 〉600.0 μm）. The grain-size components of the samples near lake center mainly contain clay（C1）, fine silt（C2） and medium-to-coarse silt（C3）. The grain-size components of the samples in the transitional area mainly include medium- to- coarse silt（C3） and fine sand（C4）. The grain- size components of samples near the shoreline mainly contain medium- tocoarse sands（C5）. The results of scatter plot show that the R/Dr is extremely significant positively corre

关 键 词：湖泊表层沉积物 粒度组分 影响因子 环境意义 

分 类 号：P343.3[天文地球—水文科学] P512.2[天文地球—地球物理学]