Abstract

The Haléo-Danielle Plateau bauxite deposit forms the largest part of the 15 km long Minim-Martap Bauxite ore district in the Adamawa Region of Cameroon. The plateau is covered with thin Upper Pleistocene to Holocene alluvial layer. It covers by laterites and bauxites formed on Tertiary-Quaternary basalts. Gibbsite and boehmite are the aluminum oxide found in the bauxite, while goethite is the main oxyhydroxide iron mineral. Bauxite rock samples from the plateau were collected and investigated with the XRF technique for their chemical composition and parent rocks. Chemical investigation reveals average concentration of the major ore components as: Al₂O₃ (43.73%), Fe₂O₃ (24.53%), SiO₂ (2.12%), and TiO₂ (3.54%). Abundant trace and rare elements include Zr (667.25 ppm), V (446.4 ppm), Ce (107.93 ppm), Sr (98.46 ppm), Nb (92.1 ppm), La (58.05 ppm), Ga (55.3 ppm), Ba (53.53 ppm), Nd (37.96 ppm), and ΣREE (245.8%). Calculations of the degree of chemical weathering (Ruxton Ratio) and geochemical coefficient (CIA) indicate that plateau rocks were subjected to intensive weathering, which led to the formation of industrial bauxite deposits. According to the results of processing the chemical composition of bauxites using three independent classification systems, plateau deposits can be classified as ferruginous bauxites. Parent rocks investigation indicates that bauxite was formed due to the decomposition of magnesium-ferrous andesite-basalts under conditions with a near neutral redox potential.

中文翻译：

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阿达玛瓦–喀麦隆Haléo-Danielle高原铝土矿的蚀变，化学过程和母岩

摘要

Haléo-Danielle高原铝土矿床是喀麦隆阿达玛瓦地区15公里长的Minim-Martap铝土矿区的最大部分。高原上覆盖着较薄的上更新世至全新世冲积层。它覆盖了第三纪-第四纪玄武岩上形成的红土和铝土矿。铝矾土和铝矾土是铝土矿中的氧化铝，而针铁矿是主要的氢氧化铁矿物质。收集了高原地区的铝土矿样品，并通过XRF技术对其化学成分和母体岩石进行了研究。化学研究表明，主要矿石成分的平均浓度为：Al ₂ O ₃（43.73％），Fe ₂ O ₃（24.53％），SiO ₂（2.12％）和TiO₂（3.54％）。痕量和稀有元素包括Zr（667.25 ppm），V（446.4 ppm），Ce（107.93 ppm），Sr（98.46 ppm），Nb（92.1 ppm），La（58.05 ppm），Ga（55.3 ppm），Ba（ 53.53 ppm），Nd（37.96 ppm）和ΣREE（245.8％）。化学风化程度（Ruxton Ratio）和地球化学系数（CIA）的计算表明，高原岩石经历了强烈的风化，这导致了工业铝土矿矿床的形成。根据使用三个独立的分类系统处理铝土矿化学成分的结果，高原沉积物可分类为铁质铝土矿。母岩研究表明，铝土矿是由于镁氧化安山岩-玄武岩在接近中性氧化还原电势的条件下分解而形成的。