CONTRASTING P-T-T LOOPS FROM SOUTHERN EAST-AFRICA, NATAL AND EAST ANTARCTICA

Thermobarometric data are compared with the similar to 1100 to similar to 500 Ma polyphase mobile belts from three separate areas of Africa and Antarctica, which originally lay in close proximity within Gondwan a. These areas are all characterized by high-grade gneiss terranes for med at similar to 1100 Ma (Grenvillian), which were subsequently rewor ked to a greater or lesser extent at similar to 500 Ma (Pan-African). In Zambia, Malawi, Zimbabwe and western Dronning Maud Land peak metamo rphic conditions at high temperatures and pressures were attained betw een 1100 and 850 Ma, followed by isothermal decompression (ITD). In Na tal and Mozambique, voluminous collision-related granitoid intrusions emplaced between 1200 and 1000 Ma gave rise to high-temperature, moder ate pressure metamorphism, with subsequent near-isobaric cooling (IBC) . The tectonic setting of these two distinct P-T-t paths can be interp reted as thrust-related uplift in a collisional setting in the case of ITD and as magmatic accretion, subsequent to collisional orogeny, in the case of IBC paths.