滇池宝象河表层沉积物粒度与元素地球化学特征研究  

Grain size and element geochemical characteristics of surface sediments in Baoxiang River of Dianchi Lake

作　　者：肖冬冬 苏斌 XIAO Dongdong;SU Bin(Kaili University,Kaili 556011,China;Faculty of Geography,Yunnan Normal University,Kunming 650500,China)

机构地区：[1]凯里学院,贵州凯里556011 [2]云南师范大学地理学部,云南昆明650500

出　　处：《水利水电快报》2024年第11期93-99,共7页Express Water Resources & Hydropower Information

基　　金：云南师范大学博士科研启动项目“滇池宝象河径流溶解态氮和颗粒态氮转化特征及机理研究”(01300205020503197)。

摘　　要：为揭示滇池入湖河流宝象河表层沉积物的粒度和元素地球化学特征,于旱、雨两季在宝象河干支流采集了20个表层沉积物样品。利用马尔文Mastersizer 2000型激光粒度仪和X射线荧光光谱仪分别进行粒度实验分析测试和地球化学元素测试。结果表明:宝象河表层沉积物以黏土质粉砂、粉砂和砂质粉砂为主,占总量的74.22%;粒径分形维数值为2.007~2.947,其中粉砂的分形维数值波动最小,粒度参数反映了宝象河沉积物以细粒物质为主的沉积学特点,且物源单一,搬运方式以悬移质为主,体现了城市河流宝象河水动力特征较弱的特点。对沉积物元素地球化学特征的分析结果表明,Zn,Cu,Ni,Pb,Cr平均含量值分别是区域背景值的2.71,4.13,1.64,1.63和1.76倍,其中Cu元素含量与背景值的比值远高于其他几种微量元素。沉积物大部分风化指数CIA值为65~85,部分为85~100,揭示了宝象河流域处于北亚热带湿润季风气候区干、湿两季分明的气候特征下岩石所经历的风化情况。In order to reveal the grain size and elemental geochemical characteristics of surface sediments in the Baoxiang River,which is a river that flows into the Dianchi Lake,20 surface sediments were collected from the mainstream and tributaries of Baoxiang River during the dry and rainy seasons.The particle sizes test and geochemical elements test were carried out by Malvern Mastersizer 2000 laser particle size analyzer and X-ray fluorescence spectrometer respectively.The results showed that the surface sediments of Baoxiang River were mainly clay silt,silty sand and sandy silt,accounting for 74.22%of the total.The fractal dimension of particle sizes were between 2.007 and 2.947,in which the fractal dimension of silt fluctuates the least.Particle size parameters reflected the Baoxiang River were dominated by fine grained matter,with single source and mainly suspended mass transport,which also reflected the weak hydrodynamic characteristics of the urban river.Geochemical analyzed of elements in sediments showed that the average content of Zn,Cu,Ni,Pb and Cr were 2.71,4.13,1.64,1.63 and 1.76 times of the regional background value,respectively,and the ratio of Cu was much higher than that of other.The weathering index CIA values of the sediments were between 65~85 and 85~100,which indicated the weathering conditions of the rocks in the Baoxiang River basin under the distinct climatic characteristics of dry and wet seasons in the North subtropical humid monsoon climate region.

关 键 词：沉积物 粒度 元素地球化学特征 宝象河流域 滇池 

分 类 号：P512.2[天文地球—地质学] P595