Poorly-ordered iron-rich precipitates from springs and streams on andesitic volcanoes
Poorly-ordered iron-rich precipitates from springs and streams on andesitic volcanoes
复制标题
安山质火山泉水和溪流中排列不良的富铁沉淀物
DOI：
10.1016/0016-7037(80)90144-1
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发表时间：
1980
影响因子：
5
通讯作者：
R. Parfitt
中科院分区：
文献类型：
--
作者：
T. Henmi;N. Wells;C. Childs;R. Parfitt
用矿物学技术研究了新西兰北岛的四个富铁矿床，其中两个出现在泉水中，一个出现在溪流中的巨石上，第四个出现在安山岩火山的河床上。它们的结构无序，成分介于水合铁和镁铁之间。电镜观察发现直径为30 Å的实心球体形成0.1 ~ 0.5 μm的聚集体。乙二醇单乙醚测量的表面积接近600 m2/g。x射线衍射显示出类似于水合铁和银辉石的弱模式。红外吸收表明，随着Fe含量的减少和Si含量的增加，Si- o的拉伸带从965到1020 cm−1发生了变化。这些频率意味着这些材料中存在Fe-O-Si键。在实验室用KOH处理脱硅，导致这些中间体转化为水合铁。
Four Fe-rich deposits, two occurring at springs, one on boulders in a stream and the fourth in a stream bed on andesitic volcanoes in the North Island, New Zealand, have been investigated by mineralogical techniques. They have poorly-ordered structure with compositions intermediate between those of ferrihydrite and hisingerite. Electron microscopy revealed solid spheres of 30 Å dia which formed 0.1-0.5 μm aggregates. Surface areas, as measured by ethylene glycol monoethyl ether, were close to 600 m2/g.X-ray diffraction gave weak patterns similar to both ferrihydrite and hisingerite. Infrared absorption showed a shift in the Si-O stretching band from 965 to 1020 cm−1with decreasing amounts of Fe and increasing amounts of Si. These frequencies imply the presence of Fe-O-Si bonds in these materials. Desilication, by treatment with KOH in the laboratory, resulted in a conversion of these intermediates towards ferrihydrite.