The aim of this subproject is to read and interpret the magmatic “signal” of processes related to Gondwana breakup and dispersal in the Mesozoic, and to the enigmatic development of the south African "superswell" which drove continental uplift into the Tertiary. The diversity of southern Africa's rifted continental margins offers a globally unique chance for comparative studies from different parts of the margins system that experienced variable intensity, composition and duration of magmatism. By studying in detail the composition of magmas produced, we can identify their sources and estimate the temperature and pressure conditions of formation. Combined with age and volume estimates, we can deduce magma flux rates for different parts of the developing margins and relate these to new geophysical and geologic constraints on style and rates of deformation, and on the regional margin architecture from the first phase of the Margins of Africa programme.

Our work will address the following key questions: Where, when and how much heat and mass were delivered into and through the rifting continental lithosphere? What were the controlling factors that determined the location and the degree of mantle melting, how and why did these factors change along the margins and in time as the margin systems evolved from the rift to drift stages. What was the relative importance of shallow-mantle convection vs. deep-mantle plumes in driving and sustaining the breakup process? To what extent is the process controlled or influenced by preexisting structures and properties of the continental lithosphere?

The key feature of this project is an integrative approach towards understanding the magmatic processes as an expression of deep-earth mass and energy transfer, how these relate to lithospheric rifting and breakup and how they influence the subsequent development of the newly formed rifted margins. Our methods are field and laboratory study of igneous complexes in key regions of southern Africa, with joint interpretation of the results using relevant geologic and geophysical data to build an earth system model for the breakup of Gondwana.

Madagascar plays a key role in the reconstruction of the Gondwana break-up history, with a rock record that spans more than 3000 Ma during which it has been episodically united with, and divorced from, Asian and African connections. However, nothing robust is known about the crustal and lithospheric structure of Madagascar because modern geophysical investigations are lacking. Here we propose an integrated approach, which includes the acquisition of new onshore and offshore geophysical deep sounding data, combined with input from geological and petrological investigations, and geochronology.

The new onshore data will advance our knowledge on structure and composition of the deep roots of continental scale shear zones, major building blocks of modern plate tectonics. Based on new magnetotelluric, seismic and onshore geologic studies we will derive a high resolution image of the crust of Southern Madagascar to establish geophysical models for the development of the deep roots of major shear zones, investigate their interaction with crustal evolution, and their impact on crust/mantle interaction. We will also investigate if present local seismicity is associated with these shear zones.

Off-shore, we will investigate the architecture and internal structure of the Madagascar Ridge, to decide if it is underlain by continental or oceanic crust and if the crustal structure is comparable to the conjugate Gunnerus Ridge in Eastern Antarctica. We also propose acquisition of modern geophysical data to investigate architecture and internal structure of the Davie Ridge and the northern continental margin of Madagascar in order to distinguish between passive-volcanic and passive-non-volcanic margin development and to investigate if the Davie Ridge could be a crustal remnant or an old plate boundary resulting from the separation of Madagascar from Eastern Africa.

The objectives of this research work shall be to subdivide and interprete the stratigraphic columns of sediments penetrated by the wells into depositional sequences and system tract. To propose a sequence stratigraphic framework for the field. To also, compare geochemistry of the core and side wall samples with the stratigraphic column to establish possible correlations. This is expected to unfold the subsurface geology as it relates to sequences and system tract, assisting in the determination of geometry of potential sands, while suggesting additional appraisal opportunities and development location. Also, to produce a model for future interpretation in well exploration. The project will employ the best geoscience methodology that will reveal accurate deepening of the basins and also, showing several cycles related to eustatic flunctuation in the study area. The depositonal models that will be generated will help in the exploration of the origin of genetically related sedimentary packages during the sea level cycles. Petrophysics will also be used to delineate additional basin parameters, and all the stratigraphic, chemical (geochemical) and petrophysical data will be used to evaluate the evolution of the continental margin.

Multiple geochemical proxies will be used to infer the evolution of the continental margin of South Africa since the Neogene (roughly the last 25 million years). Strontium isotope stratigraphy will be combined with biostratigraphy to develop an improved age model of deposition and diagenesis on the margin. Neodymium (Nd) isotopic changes will be related to changes in oceanic circulation and upwelled waters along the margin. Seismic stratigraphy will be integrated with geochemistry, litho- and biostratigraphy in order to determine the relation among climate, tectonic uplift, upwelling intensity, ocean currents (erosional events) and sea-level fluctuations. The improved age model will allow us to correlate events on the western margin with global tectonism (e.g., opening of oceanic gateways), climate (glaciation of Antarctica and the Northern Hemisphere), eustacy and ocean circulation (e.g., intensity of North Atlantic Deep Water formation). The age of Quaternary successions will be determined using oxygen isotope stratigraphy and AMS radiocarbon ages of the Holocene mud belt. High-resolution Quaternary records will be compared to continental climate proxy (including ice core) records and Northern Hemisphere records.

The goals of this project are to achieve a better understanding for the effects (i) oceanic currents have on sediment mobilization and transport and (ii) topographic highs have on paths and intensities of oceanic currents. We will test our conception of the build-up of the Agulhas Drift by different water masses via a numerical simulation of the oceanic current and sediment transport patterns. Different settings for the seafloor topography and climatology will provide information on different time slices representing the LGM and subsidence history of the Agulhas Plateau. Furthermore, we will investigate the impact of the emplacement of magmas and tectonic events both on oceanic currents and the climate. In this way we will achieve a better understanding of the sensitivity of the oceanic circulation with respect to those processes and the evolution of the current systems in the gateway south of South Africa as well as climate variations resulting from modification in current paths and tectono-magmatic events.