Lateritic weathering of Miocene volcanic rocks from western Cameroon highlands formed duricrusted bauxitic profiles. Two weathering profiles on ca. 14 Ma basalt and ca. 16 Ma trachyte were studied using geochemical mass balance functions. Less mobile elements Ti and Zr were used as references to quantify volumetric change (strain, ε), element transfer rate (τ) and geochemical mass transfers during the bauxitization process of basalt and trachyte. Conversion of parent rocks to kaolinite and goethite rich saprolites evolved to Al-Fe rich bauxites, mostly composed of gibbsite and iron oxy-hydroxides (goethite and hematite). However, formation of Al-Fe bauxitic profiles required higher Si leaching on trachyte than on basalt. Our results document that chemical weathering of a larger thickness of trachyte than basalt has been required to form a unit meter of weathering profile, implying differential rates of rock chemical erosion and topographic decay of landscapes. Rates of chemical erosion and formation of lateritic weathering profiles in western Cameroon have been mostly controlled by drainage conditions and volcanic rocks composition (mostly SiO₂ content differences), that also resulted in contrasted landscapes evolution during the Neogene.

来自喀麦隆西部高地的中新世火山岩的红土风化形成了硬壳的铝土型剖面。大约两个风化剖面 14 Ma玄武岩和约。利用地球化学质量平衡函数研究了16 Ma的小曲风。在玄武岩和菱形矿的铝土矿化过程中，较少的可移动元素Ti和Zr被用作量化体积变化（应变ε），元素转移速率（τ）和地球化学质量转移的参考。母体岩石向富含高岭石和针铁矿的腐泥土转变为富含铝铁的铝土矿，主要由三水铝石和羟基氧化铁（针铁矿和赤铁矿）组成。然而，形成铝铁铁矿型材需要在长晶矿上比在玄武岩上更高的硅浸出率。我们的研究结果表明，要形成单位米的风化剖面，就必须要有比玄武岩厚的粗粒矿物化学风化，这意味着岩石化学侵蚀和景观地形衰减的速率不同。喀麦隆西部的化学侵蚀速率和红土风化剖面的形成主要受排水条件和火山岩成分（大部分为SiO2）控制。_2个内容差异），这也导致了新近纪时期景观演变的对比。