U-Pb detrital zircon and Ar-39-Ar-40 muscovite ages from the eastern parts of the Karagwe-Ankole Belt: Tracking Paleoproterozoic basin formation and Mesoproterozoic crustal amalgamation along the western margin of the Tanzania Craton

摘要

The Karagwe-Ankole belt forms part of a complex system of orogenic belts in Central-East Africa that record the amalgamation of Archaean and/or Paleoproterozoic continental kernels in the Proterozoic. The actual timing of tectonic processes, including initial basin formation and subsequent deformation, is only poorly constrained so that the geodynamic significance of the Karagwe-Ankole belt within the broader system of Proterozoic orogens in Central-East Africa is not well understood. This paper presents U-Pb ages of detrital zircons constraining the age of sediments of the eastern parts of the Karagwe-Ankole fold belt overlying the western Tanzania Craton and Ar-39-Ar-40 muscovite ages from mylonites and phyllonites associated with the main phase of subsequent shortening and fold-and-thrust tectonics (D2).