Assessing the time-space distribution of magmatism during the opening and further evolution of the South Atlantic margins: Integrating the volumes, production rates and composition of mantle-derived magmas with dynamic models of mantle convection and surf

有关原始岩浆成分、所涉及的地幔成分的性质以及P-T条件和熔融程度的信息对于理解与南大西洋强烈岩浆活动和大陆裂解相关的地幔过程至关重要。该项目建立在纳米比亚Etendeka省现有工作的信息和经验的基础上，并集中在相对罕见的高镁含橄榄石岩石上，这些岩石最有可能保存原始熔体信息。我们利用微区分析技术的进步，获得早期形成的斑晶和熔融包裹体保存在其中的主元素和微量元素分析。计划中的研究将限制控制地幔熔融的关键参数（Mg/Fe和Ca/Al比率、挥发物含量），并区分源成分，并将提供温度-压力条件和熔融程度的估计。在受羽流影响的Etendeka省完成第一阶段工作后，我们将在下一阶段扩大调查范围，以涵盖沿离羽流越来越远的裂谷边缘沿着喷发的当代岩浆（西南-纳米比亚和南非）。

Information about the primary magma compositions, the nature of mantle components involved, and the P-T conditions and degree of melting is of central importance to understanding mantle processes associated with intensive magmatism and continental breakup in the South Atlantic. This project builds on information and experience from existing work in the Etendeka province of Namibia and concentrates on relatively rare, high-Mg, olivine-bearing rocks which are most likely to preserve primary melt information. We utilize advances in microanalytical techniques to obtain major and trace element analyses of earlyformed phenocrysts and melt inclusions preserved within them. The planned research will constrain key parameters (Mg/Fe and Ca/Al ratios, volatile contents) that control mantle melting and distinguish source components and will provide estimates of temperaturepressure conditions and degree of melting. After completion of first phase work in the plumeinfluenced Etendeka province we will expand the scope of investigation in the next phase to cover contemporary magmas erupted along the rifted margin at increasing distance from the plume (SW-Namibia and South Africa).