漫反射光谱测定云南元谋盆地古红土铁氧化物  

Rapid Quantification of Iron Oxides in Red Paleosols in Yuanmou Basin Using Diffuse Reflectance Spectroscopy

作　　者：刘延国[1,2] 刘艳秋[1] 欧阳莉莉 蔡元峰[3] 黄成敏[1] LIU Yan-guo;LIU Yan-qiu;OUYANG Li-li;CAI Yuan-feng;HUANG Cheng-min(College of Architecture and Environment,Sichuan University,Chengdu 610065,China;School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,China;State Key Laboratory of Mineral Deposits Research,Nanjing University,Nanjing 210093,China)

机构地区：[1]四川大学建筑与环境学院,四川成都610065 [2]西南科技大学环境与资源学院,四川绵阳621010 [3]南京大学金属成矿作用机制国家重点实验室,江苏南京210093

出　　处：《光谱学与光谱分析》2018年第11期3516-3520,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41771248;41371225)资助

摘　　要：铁氧化物矿物是现代土壤和古土壤的重要组成,其数量和形态是反映土壤成土条件和土壤风化发育程度的重要指标。鉴于其粒度细小、结晶度差、含量低、与粘土矿物密切共生,加之基体效应的影响,难以快速准确测定其含量;鉴于某些测试方法自身的限制,能用于铁氧化物矿物定量分析的方法也很少。在分析目前常用测量方法的基础上,选择漫反射光谱法(DRS)对云南元谋盆地所采古红土样品中的铁氧化物进行定量研究,结果表明:漫反射光谱法测得土壤样品在400～2 500nm之间,间隔2nm共1 061个波段的光谱反射率最高45%左右,各样品反射率特征较为一致;漫反射光谱一阶导数显示,光谱主峰位于575nm处,为赤铁矿的指示波谱段,次级峰位于435nm处,为针铁矿的指示波谱段;确定云南元谋古红土存在赤铁矿和针铁矿,其含量范围3～5和5～10g·kg^(-1),此结果获得XRD方法分析方法的佐证。Iron oxide is one of important minerals in modern soils and red paleosols,whil ethe quantity and morphology of iron oxides are the critical indicators for soi l-formation and weathering development.However,identification of iron oxide sin soils and sediments is challenged by its small size,poor crystallinity,low content,close bond with clay minerals and the effect of soil matrix.Here the diffuse reflectance spectroscopy(DRS)method was adopted to quantify and sem i-quantify iron oxides of red paleosols in Yuanmou Basin,southwest China.Thespectral reflectance of paleosols was about 45%,measured over the range of 40 0~2 500 nm at an interval of 2 nm with a total of 1 061 bands.Nearly all samp les exhibited the similar spectral reflectance,while the first and secondary der ivative curve peaks occurred at 575 nm for hematite and 435 nm for goethite,respe ctively.Combination of CBD method and DRS technique the concentrations of hema tite and goethitethe in red paleosols in Yuanmou Basin were 3~5 and 5~10 g·kg-1,respectively.The estimate on goethite and hematite using DRS was suppo rted by the X-ray diffraction method.

关 键 词：元谋盆地 古红土 铁氧化物 DRS 

分 类 号：O657.3[理学—分析化学]