广西北部湾地区表层土壤中Cu地球化学分布特征及影响因素研究

Geochemical and distribution characteristics of copper in topsoil of Beibu Gulf Zone in Guangxi and its influencing factors

选取广西北部湾地区表层土壤为研究对象,采集7327件土壤样品,400件岩石样品,分析K_2O、Na_2O、CaO、MgO、SiO_2、Al_2O_3、TFe_2O_3和有机碳,探讨了土壤成土母岩、成土作用、土壤组成和土壤性质等对表层土壤Cu元素的影响。结果表明,研究区表层土壤Cu元素含量低于中国土壤背景值;风化作用对于Cu元素的次生富集起到极为重要的作用,强于成土母岩元素含量背景的影响。Pearson相关分析和主成分分析结果表明,土壤组成和土壤性质等因素中,含Al矿物、含Fe矿物和有机碳(SOC)对土壤Cu的富集起到主导作用;pH和含Ca矿物起到次要作用,而含K矿物、含Na矿物和含Mg矿物的作用较弱,可以忽略不计,SiO_2则起反作用。

This paper set the topsoil of Beibu Gulf Zone in Guangxi as its object of study,and collected 7327 pieces of topsoil samples and 400 pieces of rock samples.Then it conducted analysis on K_2O,Na_2O,CaO,MgO,SiO_2,Al_2O_3,TFe_2O_3 and organic carbon,and discussed factors like soil forming rock,pedogenesis,soil constitution and soil properties.The results indicated that Cu in topsoil is less than China＇s soil background value,and weathering is more important to downward enrichment of Cu than the element content background of soil forming rocks does.According to the results of Pearson correlation analysis and principal component analysis,in terms of factors like soil constitution and soil properties,Al-bearing and Fe-bearing minerals and organic carbon have predominant influence on the enrichment of Cu in soil,and pH value and Ca-bearing minerals have subordinate influence while the influence of K-bearing,Na-bearing and Mg-bearing minerals is little and negligible.However,the content of SiO_2 has negative influence.