Banded iron formations (BIFs) are the most significant source of iron in the world. In this study, we report petrographic and geochemical data of the BIF from the Meyomessi area in the Ntem Complex, southern Cameroon, and discuss their genesis and the iron enrichment process. Field investigations and petrography have revealed that the studied BIF samples are hard; compact; weakly weathered; and composed of magnetite, subordinate quartz, and geothite. The geochemical composition of the whole rock reveals that iron and silica represent more than 98 wt% of the average composition, whereas Al₂O₃, TiO₂, and high‐field strength elements (HFSE) contents are very low, similar to detritus‐free marine chemical precipitates. The total iron (TFe) contents range from 48.71 to 65.32 wt % (average of 53.29 wt %) and, together with the low concentrations of deleterious elements (0.19 wt % P on average), are consistent with medium‐grade iron ores by global standards. This interpretation is confirmed by the SiO₂/Fe₂O_3total versus (MgO + CaO + MnO)/Fe₂O_3total discrimination plot in which most of the Meyomessi BIF samples fall in the field of medium‐grade siliceous ore. Only one sample (MGT94) plots in the high‐grade magnetite–geothite ore domain. The high Fe/Ti (376.36), Fe/Al (99.90), and Si/Al (29.26) ratios of the sample are consistent with significant hydrothermal components. The rare earth elements (REE) contents of the studied BIF samples are very low (∑REE: 0.81–1.47 ppm), and the Post‐Archaean Australian Shale (PAAS)‐normalized patterns display weak positive Eu anomalies (Eu/Eu*: 1.15–1.33), suggesting a syngenetic low‐temperature hydrothermal solutions, similar to other BIF worldwide. However, the Meyomessi BIFs show high Fe contents when compared to the other BIFs. This indicates an epigenetic mineralization process affected the Meyomessi BIF. From the above results and based on the field and analytical data, we propose that the genetic model of iron ores at the Meyomessi area involves two stages of the enrichment process, hypogene enrichment of BIF protore by metamorphic and magmatic fluids followed by supergene alteration as indicated by the presence of goethite in the rocks.

中文翻译：

---

喀麦隆南部Meyomessi地区带状铁层-来自古生界Ntem（刚果Craton）的铁矿的成因地球化学约束

带状铁层（BIF）是世界上最重要的铁来源。在这项研究中，我们报告了喀麦隆南部Ntem Complex Meyomessi地区BIF的岩石学和地球化学数据，并讨论了它们的成因和铁富集过程。现场调查和岩相学分析表明，所研究的BIF样品较硬。紧凑; 风化弱 由磁铁矿，次要石英和地矿组成。整个岩石的地球化学组成表明，铁和二氧化硅占平均组成的98％以上，而Al ₂ O ₃，TiO ₂，并且高场强元素（HFSE）的含量非常低，类似于无碎屑的海洋化学沉淀物。总铁（TFe）含量范围为48.71至65.32 wt％（平均为53.29 wt％），再加上低浓度的有害元素（平均P为0.19 wt％），与全球范围内的中品位铁矿石一致标准。这种解释是通过在SiO确认₂ / Fe的₂ ö _3total与氧化镁（MgO + CaO的+ MNO）/ Fe的₂ ö _3totalMeyomessi BIF样品大部分落入中品位硅质矿石领域的判别图。只有一个样本（MGT94）在高品位磁铁矿-沸石矿田中绘图。样品的高Fe / Ti（376.36），Fe / Al（99.90）和Si / Al（29.26）比值与重要的水热成分一致。所研究的BIF样品中的稀土元素（REE）含量非常低（∑REE：0.81–1.47 ppm），考古后澳大利亚页岩（PAAS）归一化模式显示出弱的正Eu异常（Eu / Eu *： 1.15–1.33），这是一种同质低温热液解决方案，与全球其他BIF相似。但是，与其他BIF相比，Meyomessi BIF具有较高的铁含量。这表明后生成矿作用影响了Meyomessi BIF。