【摘要】 磁铁矿和赤铁矿是自然界铁氧化物的两种主要存在形式,也是弓长岭铁矿区的主要矿石矿物,二者之间的转化曾经被认为是氧化还原反应的结果。文中根据近几年提出的非氧化还原反应成矿理论,对弓长岭铁矿区内磁铁矿/赤铁矿之间的转化关系进行新的解释。通过对弓长岭矿区矿石样品进行偏光显微镜和扫描电镜背散射等实验研究,发现了赤铁矿交代磁铁矿、针铁矿交代赤铁矿、黄铁矿与磁铁矿、赤铁矿共生等现象。结合前人研究成果,从矿物组合、矿石结构以及矿物转化前后体积变化等方面,论证了部分后生的赤铁矿是在缺氧的环境下由磁铁矿经非氧化反应转变而成,为该区后生赤铁矿的形成现象提供了一种新的解释。更多还原

【Abstract】 Magnetite and hematite are the two forms of iron oxides in natural environment, and also the main ore minerals of theGongchangling iron deposit in Liaoning province, North China. In the past, it is generally accepted that redox reaction is the onlyprocess for the conversion between magnetite and hematite. Recently, non-redox reaction theory presented an alternative transformationrelationship between magnetite and hematite for the Gongchangling iron deposit. In this study, with the polarization microscope and thescanning electron microscopy back scattering(BSE) analysis, the structure characteristics of the ore samples from the deposit wereanalyzed, including the metasomatism from magnetite to hematite, the replacement of hematite to goethite, and the paragenesis amongpyrite, magnetite and hematite. Through characterization of mineral assemblages, the structure characteristics of ores, the volumechange of the iron oxides before and after the transformation, we suggest that part of epigenetic hematite which exists in theGongchangling iron deposit may be transformed in the anoxic and reducing environment from magnetite through the non-oxidationreaction. This provides a new explanation for the formation mechanism of the epigenetic hematite in this iron deposit.更多还原