利用^(137)Cs示踪和孢粉分析法对喀斯特峰丛草地洼地泥沙沉积及侵蚀环境的研究  

Sediment Deposition and Erosion Environment in a Karst Peak-Cluster Grassland Depression Studied by ^(137)Cs Tracing Technology and Pollen Analysis

作　　者：何永彬[1] 张信宝[2] 贺秀斌[2] 

机构地区：[1]云南大学云南省地理研究所,云南昆明650223 [2]中国科学院水利部成都山地灾害与环境研究所,四川成都610041

出　　处：《水土保持通报》2013年第1期246-250,共5页Bulletin of Soil and Water Conservation

基　　金：国家重点基础研究发展计划课题"西南喀斯特山地土壤侵蚀过程与水土流失危险度评价"(2006CB403203);国家自然科学基金项目"滇东高原喀斯特环境石芽因素对土壤侵蚀相关作用的研究"(40861016);云南省应用基础研究重点项目"云南高原干旱河谷植被成因与河谷的资源环境效应"(2009CC003)

摘　　要：在贵州省茂兰喀斯特峰丛草地洼地联合运用137 Cs示踪和孢粉分析的方法,对洼地沉积泥沙剖面进行了研究。草地洼地泥沙剖面的137Cs垂直分布显示了泥沙沉积特征,以地层孢粉为主的孢粉组成显示了洼底泥沙主要来源于由碳酸盐岩石风化成土后随水流侵蚀搬运的坡地土壤颗粒。从沉积泥沙剖面的137 Cs含量、土壤颗粒结构、孢粉总浓度的垂直变化说明洼地土壤侵蚀经历了一个相对的轻微侵蚀—剧烈侵蚀—侵蚀显著减缓的变化过程;沉积泥沙剖面样品中的现代孢粉组成出现从蕨类、草本、乔木(松)孢粉占优势到以适应喀斯特石生环境的蕨类孢粉和草本孢粉占优势的变化,指示了洼地环境植被出现从含稀疏常绿落叶松的草丛退化为草丛的变化。喀斯特峰丛草地洼地的泥沙沉积过程与洼地植被演变和洼地侵蚀环境变化具有密切联系。^137Cs tracing technology and pollen analysis were jointly used to study sediment profile in a karst peak cluster grassland depression in Maolan, Guizhou Province. Vertical variations of ^137Cs, soil particle structure and pollen composition in the profile showed that soil erosion in the grassland depression occurred in a relatively varied process from slight erosion to intensive erosion and then to rapidly decreased erosion. Those modern pollen of deposited sediment samples in the profile showed that the plant constitution domina- ted by fern seed, herb seed and tree seed changed to that dominated by fern seed and herb seed which adapted to the karst rocky habitation. This means that herbosa including sparse Pinus plants degraded to herbosa in the depression. Sediment deposition process is closely associated with plant regression and erosion environ ment change in the karst peak-cluster grassland depression.

关 键 词：泥沙沉积 137Cs 孢粉分析 土壤侵蚀环境 喀斯特峰丛草地洼地 

分 类 号：P515.2[天文地球—地质学] Q914.2[天文地球—古生物学与地层学]