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南海东北陆坡区铁锰结核的特征和成因
CHARACTERISTICS AND ORIGIN OF FERROMANGANESE NODULES FROM THE NORTHEASTERN CONTINENTAL SLOPE OF THE SOUTH CHINA SEA
【摘要】 对取自南海东北陆坡区的铁锰结核成分进行了X射线衍射、中子活化和电子探针研究。结核的组成矿物有δMnO2、针铁矿、水针铁矿、石英、斜长石、角闪石、钾长石、伊利石和白云母等。铁锰成分变化较大:Fe为7 1%~16 0%;Mn为5 8%~7.7%。Cu、Co、Ni、Pb含量低,分别为0 04%~0 06%、0 11%~0 15%、0 02%~0 03%和0 05%~0 07%。Mn/Fe比值为0 7。铁锰结核从内壳层向外壳层含铁量逐渐增加,Cu、Ni含量波动降低,反映在其形成过程中受到沉积环境波动、陆源碎屑物供给增加和Mn、Cu、Ni、Co元素来量变化的影响,具有典型边缘海水沉积成因铁锰结核的特征。
【Abstract】 The compositions of ferromanganese nodules collected from the northeastern slope of the South China Sea were studied using Xray diffraction (XRD), neutron activation analysis (NAA) and electron microprobe analysis. The nodule minerals consist of quartz, plagioclase, amphibole, Kfeldspar, goethite, lepidocrocite, δMnO2, illite, and muscovite etc. The contents of iron and manganese vary largely in the nodules: Fe 7.1%~16.0%,and Mn 5.8%~7.7%. And the concentrations of Cu, Co, Ni, and Pb are lower in the nodules, which are 0.04%~0.06%, 0.11%~0.15%, 0.02%~0.03%, and 0.05%~0.07% respectively. The Mn/Fe ratio is 0.7.The concentration of Fe increases from the inner crust to the outer one, with those of Cu and Ni decreasing in different ways. It shows that the growth of the nodules was infected by the environmental fluctuations and changing supply of the terrigenous sediments and Mn, Cu, Co,and Ni. The nodules are typically hydrogenetic in margin sea environment.
【Key words】 continental slope; ferromanganese nodule; geochemistry; origin; the South China Sea;
- 【文献出处】 海洋地质与第四纪地质 ,Marine Geology & Quaternary Geology , 编辑部邮箱 ,2003年01期
- 【分类号】P744.3
- 【被引频次】28
- 【下载频次】545