强烈风化条件下玄武岩发育土壤的元素地球化学特征  

Mobilization and Redistribution of Elements in Soils Developed from Extremely Weathered Basalts on the Hainan Island

作　　者：李建武[1,2] 张甘霖[1] 李德成[1] 张鑫慧[1,2] 

机构地区：[1]土壤与农业可持续发展国家重点实验室,中国科学院南京土壤研究所,南京210008 [2]中国科学院研究生院,北京100049

出　　处：《地球与环境》2012年第4期491-498,共8页Earth and Environment

基　　金：国家自然科学基金(No.41071142);中国科学院知识创新工程重要方向项目(KZCX2-EW-405-1)共同资助

摘　　要：海南岛地处热带,晚第三纪以来喷发的玄武岩上广泛发育铁铝土。土壤剖面的常量元素、微量元素、化学风化指标及元素迁移率的研究表明:(1)土壤Al2O3、Fe2O3、SiO2和TiO2元素富集,水溶型元素强烈淋失,高CIA值和低ba值均显示其经历强烈的化学风化作用;(2)元素含量和元素迁移率的计算结果显示,温带难迁移的Ti、Zr、Hf和Nb等元素在高温多雨的热带环境下也会发生强烈的淋失,究其原因主要受湿热环境下高有机质含量和强酸性条件影响;(3)Fe、Al、Cu和Ni等元素的迁移则反映了基岩发育土壤自下而上的风化渐进特征;(4)表层土壤K、Na和Sr元素的强烈富集则与大气沉降有关。The Hainan Island is located in a tropical zone and most of the ferralsol profiles that developed on Neogene basalt in this region have undergone extensive weathering. Major, trace and organic elements of a laterite profile were reported to inves- tigate elements mobilization and redistribution in tropical regions. The results indicate that SiOz, A12O3 and Fe2O3 are the dom- inant chemical components, CaO, Na2O, MgO and K2O concentrations are extremely low and CIA and CIW values are high for ali soil samples. These results suggest that the profile has undergone extremely strong weathering. The strongly acidic environ- ment and organic matter （OM） can remarkably improve the transfer of insoluble elements. As for the general conservative ele- ments during incipient chemical weathering, such as Ti, Zr, Hf and Nb, the removals are up to 30%-40% in the upper pro- file; and Fe, A1, Cu and Ni are removed from the upper profile, transferred downwards, and then precipitated in the lower profile. In addition, atmospheric inputs, including sea salt aerosol and dust, have a profound effect on the budgets of elements that are susceptible to leaching-induced losses （e. g. K, Na and Sr）. The overall elemental behaviors in this profile suggest that organic matter and atmospheric inputs play a very important role in the mobilization and redistribution of elements during ex- treme weathering in tropical regions.

关 键 词：玄武岩 土壤 痕量元素 海南岛 

分 类 号：P595[天文地球—地球化学]