长江中下游地区第四纪红土中铁锰结核空间分异的规律及机理

Quaternary Red Clay is widely distributed in the middle and lower reaches of the Changjiang River. Generally, its standard profile is including roof loess layer, typical Red Earth, Vermicular Red Earth and gravel deposits. Because of the different degrees of eroding, the roof loess layer is sometimes disappeared. The typical Red Clay is usually in brown-red or dark red color, and have the homogeneous color. In the bottom of the typical Red Clay layer, we can usually see some ferromanganese film and nodules. Vermicular Red Clay is usually composed with dark bedrock and yellow or white stripe. In the top of Gravel deposits is, sometimes, appear the vermicular styles.There are many stratiform ferromanganese nodules in the typical Red Clay and Vermicular Red Clay..So far, there are many researches about the ferromanganese nodules in soil, such as the character of geochemistry, the cause of formation, and so on. As the offspring of environment change, the ferromanganese nodules must have inspected by nature factors. As we know, the nature factors are different in different place. Through the research of the differentiation of the ferromanganese nodules in the area, contrast the differentiation of the nature factors, we can know the relationship between the ferromanganese nodules and the nature factors. But the research of the relationship is very simple. .The main study area of this project is the middle and lower reaches of the Changjiang River, such as Hunan, Jiangxi, Zhejiang, Anhui, etc. With the integrated use of the theory and methods in the field of ICP-AES, XRD, SEM, Laser Particle Analyzer, the project planed to study the layer characteristics, the external morphological characteristics, internal structure, geochemistry characteristics and the chronology of the ferromanganese nodules in the Red Clay. Through the analysis of spatial differentiation and it's Mechanism of the ferromanganese nodules in the Red Clay, compared to previous research on Quaternary Red Clay, the project planed to clarify the relationship between the ferromanganese nodules and the natural environment, summed up the role and significance of Quaternary red ferromanganese nodules in the study of environmental change, enriched Quaternary red clay sediment contents, provide some basic data and theoretical support.

长江中下游低山丘陵区广泛分布着第四纪红色粘土，第四纪红土中发育大量富含铁锰的、成层状分布的次生结核体。目前对土壤中铁锰结核的研究集中在其物质组成的测定、形成原因的推测等方面，忽略了结核在空间上的分异特征及其与降水、气温等自然环境要素空间分异的关系。本项目以长江中下游地区的湖南、江西、浙江、安徽等地为主要研究区，综合运用电感耦合等离子光谱法、X荧光衍射法、扫描电子显微镜法及激光粒度法、筛分法等方法和技术，对第四纪红土结核的发育层位特征、外部形态特征、内部构造特征及地球化学特征等方面做系统研究，探究第四纪红土结核在水平及垂直空间的分异规律，对比前人关于第四纪红土的研究成果，分析自然因素对铁锰结核空间分异的作用机理，进一步明确铁锰结核在第四纪红土与环境变化研究中的作用与意义，项目将丰富长江中下游地区第四纪红土沉积物的研究内容，为该地区古气候与古环境研究提供一些基础数据和理论支撑。

长江中下游低山丘陵区广泛分布着第四纪红色粘土，第四纪红土中发育大量富含铁锰的、成层状分布的次生结核体。本项目以长江中下游地区的湖南、江西、浙江、安徽等地为主要研究区，通过对第四纪红土及其中发育的铁锰结核的发育层位特征、颜色、大小、圆度等外部形态特征及地球化学特征等方面做系统研究，获得了第四纪红土结核在水平及垂直空间的分异规律。运用漫反射光谱环境磁学等方法对结核及其母质中的铁矿物类经进行了分析，阐述了结核发发育过程的环境变化特征。通过对结核发育的红土母质的粒度、常微量元素、稀土、环境磁学等指标的分析，阐述了红土母质的物质来源、搬运动力以及风化过程等，对结核的形成提出了初步的研究结论。在实验过程中发现并阐述了铁锰结核的存在对红土粒度分析的影响。