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对南海北缘新生代玄武岩中幔源包体的研究揭示了该地区上地幔的不均一性和复杂的地幔过程。部分橄榄岩中单斜辉石(Cpx)具有极低的Ti含量(<160μg/g),这与这些样品中较高的Cpx含量(8%～12%)不匹配。主元素成分变化趋势以及Cpx中HREE分异现象,暗示该区上地幔经历了变压熔融。地幔熔融始于深部的石榴子石稳定区并延续到浅部的尖晶石稳定区(总熔融程度达23%)。这些熔融残余受到了硅酸盐和含水流体的交代。橄榄岩的微量元素组成指示南海北缘地幔具有大陆裂谷型地幔的特征,而与俯冲带之上的地幔楔或受俯冲作用影响的地幔有很大的差别。包体的平衡温度和橄榄石中Fo之间的负相关关系暗示岩石圈地幔具成分分层结构。该地幔的下部由大洋型橄榄岩组成,而地幔顶部为类似于太古宙-元古宙地幔的富斜方辉石方辉橄榄岩。这一岩石圈结构与该地区岩石圈的减薄和软流圈对老岩石圈的置换有关。深源岩石记录的信息支持南海海盆是陆缘扩张引起的主动盆地的观点。
The study of the mantle-derived inclusions of the Cenozoic basalts in the northern margin of the South China Sea revealed the heterogeneity of the upper mantle and the complex mantle processes in the area. Cpx in some peridotites has very low Ti content (<160 μg / g), which does not match the higher Cpx content (8-12%) in these samples. The trend of main element composition and HREE differentiation in Cpx suggest that the upper mantle underwent the transformation melting. Mantle melting begins in the deep garnet stability zone and continues into the shallow spinel stabilization zone (total melting of up to 23%). These molten residues are confused with silicates and aqueous fluids. The trace element composition of peridotite indicates that the mantle of the northern margin of the South China Sea is characterized by a continental rift-type mantle, which is quite different from the mantle wedge above the subduction zone or the mantle affected by the subduction. The negative correlation between the equilibrium temperature of the inclusions and the Fo in olivine suggests that the lithospheric mantle has a layered composition. The lower part of the mantle is composed of peridotitic peridotites and the top of the mantle is enriched in a hectorite-harzianite similar to the Archean-Proterozoic mantle. This lithosphere structure is related to the thinning of lithosphere and the replacement of asthenosphere by asthenosphere in this area. Information from deep-sourced rock records supports the view that the South China Sea Basin is an active basin caused by marginal expansion.