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

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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).