Electron Microscoplc and mineralogical studies on biologically induced metal ores and minerals

研究生物诱导的金属矿或矿物相是一个有趣的课题。这些过程对地球的表面环境和地球历史都有很大的影响。本课题选择了三个主要的子课题：（1）生物成因铁矿的形成过程，如群马狮子矿，（2）古老和现代叠层石构造及其特征，（3）生物成因（磁铁矿到细菌）磁铁矿。这些研究的主要成果之一是关于（1）群马铁矿。以下是摘要。本文对该铁矿的沉积铁矿石进行了理论描述。该铁矿石由纳米晶针铁矿、结晶良好的黄钾铁矾和极少量的硫铁矿组成。特征矿石类型包括厚条带状铁矿、薄条带状狮子矿和富含苔藓和/或树叶的化石集合体矿石。在粗带状矿石中，针铁矿带中保存有明显的藻类化石。晶格成像显示针铁矿纳米晶体的特征晶体学取向。细条带状狮子矿可能是细菌铁生物矿化作用的产物。这些条带可能归因于生物或季节性节律。在pH值为2-3、富Fe ~（2+）和SO_4 ~（2+）的水流中，发现了各种生物矿化产物<2->：Fe-P-（S）到Fe-S-（P）沉淀。苔藓和绿色藻类也在细胞内和细胞周围收集铁沉淀物。这些矿石被认为是生物成因的铁矿。(2)锰叠层石既见于日本（作为现代温泉沉积物），也见于澳大利亚前寒武纪地层。(3)对磁铁矿进行了矿物学和晶体异相检验。

It is interesting to investigate biologically Induced metal ore or rnineral phases. The processes have much impact to Earth'ssurf ace environments and also on Earth History. In this project, three major sub-themas were selected : that is, (1) Formation processes of biolocgically induced iron ore, such as Gunma lion Mine, (2) Old and recent stromatoilte structures and their characteristics, and (3) biogenic (magne to tactic bacterial) magnetite. One of the major results of these studies is about (1) on Gunma Iron mine. The following is the summary. Sedimentary iron ores From the Iron Mine were mine ralogically described .The Iron ore is composed of nanocrystalline goethite, well crystallized jarosite and very small amounts of strengite. Characteristiciron-ore types include thick-banded iron, thin-banded lion ore and fossil-aggregate ore rich in moss and/or leaves. Algal fossils are clearly preserved in the goethite bands in the thick-banded ore. Lattice imaging howed characteristic crystallographic orientations of the goethite nanocrystals. The thin- banded lion ores may probably formed by bacterial iron biominera1ization. The bandings may be attributed to biological or seasonal rhythms. Various products of biomineraIization are found in the present pH 2-3, Fe2^<2+>-and SO_4^<2-> rich streams ; Fe-P-(S) to Fe-S-(P) precipitates. Mosses and green algae are also collecting Fe precipitates in and around the cells. These ores are regarded as Biologicaly Induced lron Ore. (2) Mn stromatolite were found both from Japan (as recent hot springsediments), and from Australia precambrian strata. (3) The magnetite was mine ralogically and cryst allographically examined.