The Adamawa Volcanic Massif of the Cameroon Volcanic Line (CVL) is dominated by silica-undersaturated basaltic lavas, which have been attributed to plume volcanism. However, the relative contributions of peridotite and pyroxenite sources have not been assessed. Here, we present mineral and whole-rock data for the lavas to consider this issue and to better understand their petrogenesis and source mineralogy. The lavas are porphyritic, with phenocrysts and micro-phenocrysts of olivine, and to a lesser extent, clinopyroxene, in a groundmass of plagioclase, oxides, and apatite. The lava compositions are all basanites. They are silica-undersaturated and are primitive, mantle-derived melts. The basanites display lower CaO and CaO/Al₂O₃ ratio but higher Fe/Mn values than expected for melts of peridotite, consistent with an appreciable contribution from melting of pyroxenite in the source.

Olivine phenocrysts are characterized by low CaO and NiO contents but higher Fe/Mn ratios than those of olivine in melts of peridotitic sources, supporting the contribution of pyroxenite to the primary melts, and that the main mantle source lithology for the basanites was a mixture of spinel-facies peridotite and silica-deficient pyroxenite. The presence of both pyroxenite and peridotite xenoliths in this area attests to the contribution of these two mantle lithologies to the primary melts, and their relative contribution varies on a very local scale. Significant contamination by crustal materials during magma ascent is ruled out. The Youkou basanites provide a key for improving the general understanding of melt production in lithologically heterogeneous mantle beneath the CVL. Beneath the Youkou volcano, partial melting of pyroxenite by decompression formed silica-deficient melts at 60-80 km depth, which modified the peridotite mantle source by a low degree melt enrichment process indicated by the enrichment in incompatible elements. This modified mantle source then underwent low-degree melting to produce the basanitic melts, which are concentrated in a linear zone focused by the combination of the northern edge of the Congo craton and the Central African Shear Zone.

喀麦隆火山线 (CVL) 的阿达马瓦火山地块主要是二氧化硅不饱和的玄武岩熔岩，这归因于羽状火山作用。然而，尚未评估橄榄岩和辉石来源的相对贡献。在这里，我们提供了熔岩的矿物和全岩数据，以考虑这个问题并更好地了解它们的岩石成因和来源矿物学。熔岩呈斑状，在斜长石、氧化物和磷灰石的基质中含有橄榄石斑晶和微斑晶，在较小程度上还有单斜辉石。熔岩成分都是巴桑石。它们是二氧化硅不饱和的，是原始的、地幔衍生的熔体。巴桑石显示出较低的 CaO 和 CaO/Al ₂ O ₃比，但 Fe/Mn 值高于橄榄岩熔体的预期值，这与源中辉石岩熔化的显着贡献一致。

橄榄岩斑晶的特点是 CaO 和 NiO 含量低，但 Fe/Mn 比高于橄榄岩源熔体中的橄榄石，支持辉石岩对原生熔体的贡献，并且黑曜石的主要地幔源岩性是尖晶石相橄榄岩和缺硅辉石岩。该地区同时存在辉石岩和橄榄岩捕虏体证明了这两种地幔岩性对原生熔体的贡献，并且它们的相对贡献在非常局部的范围内变化。排除了岩浆上升过程中地壳物质的严重污染。尤口玄武岩为提高对 CVL 下岩性非均质地幔中熔体生产的一般认识提供了关键。幽口火山下，通过减压使辉石岩部分熔融，在 60-80 公里深度形成了缺硅熔体，通过不相容元素富集表明的低度熔体富集过程改变了橄榄岩地幔源。然后，这种改良的地幔源经历了低度熔融，产生了玄武岩熔体，这些熔体集中在由刚果克拉通北部边缘和中非剪切带结合而成的线性区域。