富水水库中微生物成因的显微针铁矿及其对微量元素的富集

通过对湖北省富水水库坝基渗漏水及其析出物的研究,探讨了现代沉积环境(水库)中显微铁矿物形成的机理及微生物在铁的生物矿化中的作用和意义.对析出物中微量元素的富集特征也进行了初步研究.用化学分析方法测试出坝基渗漏水中阳离子以Ca2+、Mg2+、k+、Na+为主,Fe2+和Fe3+含量极少,阴离子以HCO-3为主.析出物的化学成分以铁的氧化物为主.采用X射线衍射、差热分析、红外光谱和穆斯堡尔谱,以及透射电镜和扫描电镜等测试手段,分析研究了析出物的物相和形貌特征.析出物的主要矿物相为针铁矿、石英、伊利石、蒙脱石及微量方解石,呈弱结晶状态.由析出物中显微针铁矿特殊的形貌特征及其特征的穆斯堡尔谱图推测出富水水库沉积环境中显微针铁矿是由铁细菌形成.ICP-MS测试测试结果表明,析出物中不仅富集了铁,还富集了Yb、Pb、Dy、Zn、Co、Be、Eu、Sm和Tb等微量元素.微量元素的富集是微生物与显微针铁矿共同作用的结果.

The Micro-goethite of Microorganism Origin in Fushui Reservoir and Its Enrichment of Trace Elements

In this paper, the authors have studied the sediments from the percolation water in Fushui Reservoir, discussed the cause for the formation of micro goethite in modern depositional environment (reservoir) as well as the action and the significance of microorganism in the mineralization of iron. The enrichment of trace elements has also been investigated. Tests show that the main cations in the percolating water include Ca 2+ ,Mg 2+ ,K + and Na+,with minor Fe 2+ and Fe 3+ ,whereas the main anion is HCO - 3.The sediments from the percolating water are mainly oxidized products of iron.The mineral phase and the form of the sediments from percolating water in Fushui reservoir were studied by such means as X ray diffraction,infrared spectroscopic analysis,Mossbauer spectrum,transmission electron microscope (TEM) and scanning electron microscope (SE M).The main mineral phases include goethite,quartz,illite,montmorillonite and small amounts of calcite, in the form of slight crystallization. The Mossbauer spectral characteristics and the special form of goethite imply that goethite owes it formation to ferrobacteria. The trace elements were determined by ICP-MS. The sediments concentrate not only iron but also several trace elements such as Yb, Pb, Dy, Zn, Co, Be, Eu, Sm and Tb. The enrichment of trace elements results from the reaction between microorganism and micro goethite.