Lithospheric Control of Melt Generation Beneath the Rungwe Volcanic Province and the Malawi Rift, East Africa

The EarthCube BALTO (Brokered Alignment of Long-Tail Observations) project is aimed at developing new cyberinfrastructures that enables brokered access to diverse geoscience datasets. Towards achieving this BALTO objective, we developed a plug-in for the community extensible NSF open-source code ASPECT (Advanced Solver for Problems in Earth’s Convection) that permits ASPECT to read data from the BALTO server (OPeNDAP’s Hyrax open-source data server) over the web. We present a use-case of the BALTO-ASPECT client, which accesses lithospheric structures from the BALTO server to constrain a 3-D lithospheric modulated convection (LMC) modeling and melt generation beneath the Rungwe Volcanic Province (RVP) and the Malawi Rift. We test the hypothesis that at least part of the melt feeding the RVP is generated from LMC. In the model, we assume a rigid lithosphere, while for the asthenosphere we use non-Newtonian, temperature-, pressure- and porosity-dependent creep laws of peridotite. We find that a significant percentage of decompression melt from LMC occurs at a maximum depth of ~200 km beneath the axis of the Malawi Rift, consistent with the location and maximum depth of imaged low velocity zones. At shallower depths (~100 km), the melting region is focused beneath the RVP where there is rapid (~3 cm/yr) upwelling. Our results suggest that asthenospheric upwelling due to LMC is the main source of melt beneath the RVP and might also entrain the plume head materials with reported high 3He/4He values. We, therefore, propose that part of the melt beneath the northern Malawi Rift feeding the RVP can be generated by LMC without necessitating plumes impinging the base of the lithosphere at present. This use-case demonstrates the capability of the BALTO-ASPECT client to accelerate research by brokering input data from the BALTO server for modeling LMC and melt generation.