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

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.