Lithospheric Control of Melt Generation Beneath the Rungwe Volcanic Province, East Africa: Implications for a Plume Source
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Description: This contribution is provided to complement the manuscript published in 2021 in Journal of Geophysical Research: Solid Earth by these authors. The paper is entitled Lithospheric Control of Melt Generation Beneath the Rungwe Volcanic Province, East Africa: Implications for a Plume Source Here we provide our 3D lithospheric-modulated convection model that incorporates melt generation beneath the Rungwe Volcanic Province (RVP), a volcanic center in the magma-poor Western Branch of the East African Rift. The 3D LMC was simulated using the open source code ASPECT version 2.2.0-pre. The aim of this work is to investigate the source of sublithospheric melt beneath the RVP. We test the hypothesis that sublithospheric melt feeding the RVP can be generated from LMC. We develop a 3D thermomechanical model of LMC beneath the RVP and the Malawi Rift and constrain parameters for sublithospheric melt generation due to LMC. We assume a rigid lithosphere and use non-Newtonian, temperature-, pressure- and porosity-dependent creep laws of anhydrous peridotite for the sublithospheric mantle. We find a pattern of upwelling from LMC beneath the RVP. The upwelling generates melt only for elevated mantle potential temperatures (Tp), which suggests a heat source possibly from plume material. At elevated Tp, LMC associated decompression melt occurs at a maximum depth of ~150 km beneath the RVP. We suggest upwelling due to LMC entrains plume materials resulting in melt generation beneath the RVP. The models provided are contained in the following directories : 1. njinju_et_al_2021_JGR_1800K_normal_litho 2. njinju_et_al_2021_JGR_1800K_litho_minus10 3. njinju_et_al_2021_JGR_1800K_litho_plus10 4. njinju_et_al_2021_JGR_1723K_normal_litho These directories are respectively models of LMC for a mantle potential temperature of 1800 K and: (1) a normal lithospheric thickness (updated Fishwick, 2010); (2) the normal lithospheric thickness minus 10 km; (3) the normal lithospheric thickness plus 10 km and (4) models of LMC for a mantle potential temperature of 1723 K and a normal lithospheric thickness. The above models (directories) include files that allow for visualization in 3D using the software VISIT or PARAVIEW. Visualization parameters include: temperature field, viscosity, density, pressure, compositional fields, mesh, and velocities. We also provide the csv files of our modeling outputs and inputs that are described as follow: The outputs of the model "njinju_et_al_2021_JGR_1800K_normal_litho" are extracted in csv format at 10 Ma, 17 Ma and 20 Ma timesteps as in the following files: a. njinju_et_al_2021_JGR_1800K_normal_litho_10Ma.csv b. njinju_et_al_2021_JGR_1800K_normal_litho_17Ma.csv c. njinju_et_al_2021_JGR_1800K_normal_litho_20Ma.csv Each of these csv files contain 16 columns with the following names: "velocity:0","velocity:1","velocity:2","p","T","crust","mantle_lithosphere","porosity","peridotite","density","viscosity","melt_fraction","nonadiabatic_temperature","Points:0","Points:1","Points:2". These csv files can be used to extract information from the model and plot in another software such as Generic Mapping Tools (GMT).