Lithospheric Evolution in the Tanzanian Craton and Adjoining Mozambique Belt, East Africa: Perspectives From the Lower Crust

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This work will determine the thermal history of Tanzanian continental crust to understand mantle and plate tectonic processes. Rocks of the Mozambique mobile belt formed in the Archean, but were strongly heated and recrystallized during two separate mountain-building events: the ~2.0 Ga Usagaran orogeny and the ~600 Ma pan-African orogeny. The craton-mobile belt boundary also forms the site of present-day continental rifting, along a presumed site of pre-existing weakness in the plate. Samples from the Mozambique Belt will be studied with various techniques to determine their pressure-temperature history, especially dating uranium-rich minerals whose radioactive clocks are reset at different temperatures. The measurements will track the evolving thickness of the plate through time, and the amount of hot, mantle-derived magmas that intruded the crust during the mountain-building events. These results will shed light on the behavior of continental plates during mountain building and rifting, as well as the parameters responsible for localization of weakness within the continental plate. The work will involved scientists from the University of Maryland, the University of Dar-es-Salaam, and MIT.