摘要
粒度分析是研究沉积物组成特征,重建古气候变化的重要手段之一.由于有机质会影响沉积物颗粒的组成状态,因此其去除程度会对粒度测试结果产生很大影响.粒度分析是风成沉积最常用的分析方法,本研究选取古土壤、弱发育古土壤、黄土、砂黄土四种有机质含量不同的沉积物样品为对象研究有机质去除程度对粒度测量结果的影响.结果显示,彻底去除有机质后的古土壤平均粒径明显增加,说明在古土壤中有机质主要以细颗粒形式存在;弱发育古土壤和黄土的平均粒径随着有机质的去除逐渐降低,说明其中的有机质以较大颗粒的形式存在并且对沉积物产生了胶结作用;而对于砂黄土,有机质的去除程度对样品粒度测量结果影响不大,因为有机质含量较少.同时文章分析了不同有机质去除方法的优缺点,并探讨了本研究的发现对于光释光测年等需要进行有机质去除的实验的应用意义.
Grain size analysis is one of the important indicators of studying aeolian deposits and re-building the paleo-climate change. There are large amounts of organic matter and carbonate in sediments which will make the soil particle glue together, so they have great influence on grain size results. This ar-ticle selects four kinds of sediment samples which have different organic matter content as the research object. These samples were performed using different pretreatment methods before their grain-size distri-bution were measured, respectively. The experimental results show that the pretreatment methods and time for the grain size measurement procedures have certainly influenced on results of grain size distribu-tion. The mean grain size of paleosol sediment after removal of organic matter increased significantly,in-dicating that the accumulation of organic matter in the paleosol is mainly associated with the fine particu-late component occurs. The mean grain size of weakly developing paleosol and loess are bring down with the removing of organic matter. It suggests that the organic matter is in the form of larger particles and the cementation of the sediments. The measurements of sandy loess show that the removal of organic matter in these samples are inapparent. Because there is little organic matter in sandy loess. At the same time,this article analyzes the advantages and disadvantages of different pretreatment methods and dis-cusses the research significance of other experiment such as optically stimulated luminescence dating.
出处
《聊城大学学报（自然科学版）》
2016年第4期39-45,89,共8页
Journal of Liaocheng University:Natural Science Edition
基金
国家自然科学基金项目(41462006
41672167)
山东省自然科学基金项目(ZR2015JL015
ZR2015DL008)资助
关键词
有机质
粒度分析
古土壤
前处理方法
organic matter,grain size analysis,paleosol,pretreatment methods
