岭南东江流域末次间冰期强网纹红土主元素特征  

Major element characteristics of strong reticulate red earth in Dongjiang River Valleys,southern Nanling Mountains during Last Interglacial Stage

作　　者：温小浩[1] 李保生[1] 郑琰明[1] 叶建萍[1] 李后信[2] 范小平[1] 吕映霞[1] 杜恕环[1] 牛东风[1] 

机构地区：[1]华南师范大学地理科学学院,广东广州510631 [2]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地球化学》2008年第5期445-454,共10页Geochimica

基　　金：国家自然科学基金(40471139);高等学校博士学科点专项科研基金(20070574005);国家重点基础研究发展计划项目(2004CB720206);中国科学院地球环境研究所黄土与第四纪地质国家重点实验室开放基金项目(SKLLQG0309);中国科学院知识创新工程重要方向项目(KZCX2-SW-118)

摘　　要：岭南东江流域临江剖面下部含一套总厚约4.35m的弱网纹红土和强网纹红土,其顶部热释光(TL)年龄为(71.4±6.6)kaB.P.;与邻区地层对比推测,该强网纹红土形成时代为末次间冰期。该强网纹红土主元素分析结果显示,其以湿润型元素SiO2、Al2O3和TFe为主,分布范围依次60.32%～67.81%、17.52%～21.32%和4.17%～5.96%;干旱型元素Na2O、CaO和MgO含量均小于0.50%,表现为强烈淋溶。该强网纹红土主元素分布特征、风化特征值、CIA(化学蚀变指数)值都表明其属中等富铝化红土,其风化强度稍低于广西百色网纹红土而接近于江西修水网纹红土。A series of weak and strong reticulate red earth with total thickness of 4. 35 m was found at the lower part of Linjiang Profile in the Dongjiang River Valleys of southern Nanling Mountains. The thermoluminescence age at the top of the weak reticulate red earth was （71.4 ± 6. 6） ka B. P., and in contrast to the Linjiang Profile and other profiles in adjacent regions, it could be presumed that the age of the strong reticulate red earth was within the Last Interglacial Stage. The results of major elements show that the strong reticulate red earth was mainly composed of SiO2, Al2O3 and TFe, which tend to be easily assembled under warm and wet conditions, and their contents range from 60. 32% to 67.81%, 17.52% to 21.32% and 4. 17% to 5.96%, respectively; other major elements such as Na2O, CaO and MgO, which tend to be easily eluviated under warm and wet conditions, and their contents are all below 0. 50%, showing being violently eluviated. The strong reticulate red earth belonged to moderate abundant-aluminium on the bases of the major element distributings, weathering eigenvalues and CIA values （weathering intensity index）, and its weathering intensity was much close to that of the reticulate red earth in the Xiushui Profile of Jiangxi Province but weaker than that of the reticulate red earth in Baise of Guangxi.

关 键 词：末次间冰期 强网纹红土 主元素 风化强度 临江剖面 东江流域 

分 类 号：P595[天文地球—地球化学] P534.63[天文地球—地质学]