岭南东江流域一级阶地网纹红土的时代及其粒度特征  

Ages and Grain-Size Characteristics of Reticulate Red Clay on First Terrace in Dongjiang River Basin,Southern Nanling Mountains

作　　者：温小浩[1] 李保生[1,2] 郑琰明[1] 杜恕环[1] 牛东风[1] 李后信[3] 叶建萍[1] 

机构地区：[1]华南师范大学地理科学学院,广东广州510631 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安710061 [3]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地理与地理信息科学》2009年第5期59-63,共5页Geography and Geo-Information Science

基　　金：国家自然科学基金项目(40471139);高等学校博士学科点专项科研基金项目(20070574005);国家重点基础研究发展计划项目(2004CB720206);中国科学院西安地球环境研究所黄土与第四纪地质国家重点室开放基金项目(SKLLQG0809);中国科学院知识创新工程重要方向资助项目(KZCX2-SW-118)

摘　　要：岭南东江流域临江剖面含一套总厚约4.35 m的弱网纹红土和强网纹红土,其顶部年龄为71.40±6.60 TLkaB.P.,近底部50 cm年龄为99.10±5.90 OSL kaB.P.。粒度结果显示,弱网纹红土和强网纹红土都为粉砂质粘土,但前者颗粒比后者要粗,前者含较多的砂(>50μm),在粒度频率分布上呈显著双峰态;后者含较多粉砂和粘土,呈近似单峰态。以粘土或胶体粘土含量反映的强、弱网纹红土的风化程度与深海Specmap和Sulu sea氧同位素曲线指示的末次间冰期-末次冰期早期的全球冰量和西太平洋海面温度变化的趋势均颇为相似。这些证据表明,临江剖面网纹红土的形成时代应属晚更新世,即末次间冰期至末次冰期早期。A series of weak reticulate red clay and strong reticulate red clay with total thichness of 4.35 m were observed at Linjiang profile on the first terrace,Dongjiang River Basin, southern Nanling Mountains. The top age of weak reticulate red clay is 71.40±6.60 TL kaB. P. ,and the age near the bottom of the reticulate red clay is 99.10±5.90 OSL kaB. P.. The results of grain-size analyses show that both reticulate red clay are mainly composed of silty clay, but weak reticulate red clay is more coarser than strong reticulate red clay,the former contains more sand（〉50 μm） contents and displays markedly bimode grain size distribution;the latter consists of more silt and clay and displays approximately single peak in grain-size distribution. The weathering degree reflected by clay or colloid clay of strong and weak reticulate red clay corresponds to the peak values of Specmap and Sulu sea oxygen isotope curves,which is indicative of the fairly warm and humid periods from the last interglaciation to the early of last glacial. All these evidences make clear that the reticulate red clay in Linjiang is likely to be formed during the early late Pleistocene,i. e. ,from the last interglacial to the early last glacial.

关 键 词：东江流域 临江剖面 一级阶地 网纹红土 粒度特征 

分 类 号：S151.9[农业科学—土壤学]