The Proterozoic Choma-Kalomo Block, SE Zambia: exotic terrane or a reworked segment of the Zimbabwe Craton?

•The Choma-Kalomo Block has a previously undated Palaeoproterozoic (2.04–1.86Ga), metasedimentary component, and is thus not solely Mesoproterozoic in age.•The Choma-Kalomo Block is not an exotic terrane with respect to the Zimbabwe Craton, Magondi Belt or Dete-Kamativi Inlier.•Mineralisation (in the form of tin-bearing pegmatites) within both the Choma-Kalomo Block and Dete-Kamativi Inlier occurred c. 1030–920Ma.•A difference in lithospheric thickness could explain the varying rheological responses of the Choma-Kalomo Block and Dete-Kamativi Inlier.