长江口潮滩植物对沉积物铁的地球化学循环及磁性特征的影响  

Influence of Plant on Geochemical Cycling of Iron and the Magnetic Properties of Intertidal Sediments in the Yangtze Estuary

作　　者：韩晓非[1] 张卫国[2] 陈满荣 俞立中[2] 

机构地区：[1]华东师范大学地理系,上海200062 [2]华东师范大学河口海岸国家重点实验室,上海200062 [3]扬州大学地理系,江苏扬州225009

出　　处：《沉积学报》2003年第3期495-499,共5页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目 (批准号 :40 1 31 0 2 0 ;40 0 0 1 0 2 0 ;49871 0 68);教育部博士点基金项目 (980 2 691 5);上海市重点学科建设项目;上海市科委青年科技启明星项目 (0 1QC1 4 0 1 6)资助

摘　　要：通过长江河口高潮滩芦苇带沉积物柱状样CYLWA 1活性铁、有机质、粒度分析及磁性测量 ,探讨潮滩植物对沉积物铁的地球化学循环及磁性特征变化的影响。结果显示 ,沉积物柱状样总体上以Fe2 + 占优势 ,且含量随深度逐渐增加。但在亚表层 (10～ 2 0cm) ,由于根系的释氧作用 ,存在着以Fe3 + 占优势的氧化层。在 10～ 2 0cm这一氧化层 ,指示细颗粒磁性矿物的参数 (χfd、χARM)明显减小 ,而反映磁性矿物类型的参数 (BCR、SIRM/ χ)显著增大 ,指示了亚铁磁性矿物颗粒变粗 ,不完整反铁磁性矿物明显富集 。One core (CYLWA-1) from Phragrmites australis vegetated tidal flat, the Yangtz e Estuary, is selected to investigate the effect of plant on geochemical cycling o f iron and the magnetic properties of the sediments. The results show that Fe 2+ dominates in most layers of the sediments and increases with depth, except at a depth of 14～20 cm, where Fe 3+ dominates due to the abundant distribution of live roots. In the oxidized layer of 14～20 cm , χ fd , χ ARM and χ ARM /SIRM decline, sug gesting coarsening of ferrimagnetic minerals. On the contrary, the obvious incre ase in B CR and SIRM/ χ indicates relative increase of imperfect an ti-ferromagneti c minerals. It is suggested that ferrimagnetic minerals be transformed into impe rfect anti-ferromagnetic iron oxides under oxidizing environment.

关 键 词：长江口 潮滩植物 沉积物 铁 地球化学循环 磁性特征 

分 类 号：P736.41[天文地球—海洋地质]