A Discussion on the evolution of the Precambrian crust - The Rhodesian Archaean craton — an essay in cratonic evolution

Abstract

The Rhodesian Archaean craton consisting largely of granite-greenstone terrain is briefly described, and is discussed mainly in the light of points arising from recent work in the south and central parts of the country. The Sebakwian-Bulawayan-Shamvaian terminology and the evidence for more than one age of greenstone belt development are reviewed. An attempt is made to trace the evolution of the craton from the earliest recognized rocks up to the emplacement of the Great Dyke (±2500 Ma). Evidence is presented for the existence of an earlier sialic basement to the main greenstone belt cover, and to show that the main greenstone belts developed during the approximate time-span 3300 to 2900 Ma. Between approximately 2900 and 2500 Ma the main events are traced both in the craton and the Limpopo mobile belt. Proterozoic events at 2000 to 1800 Ma affecting the craton and mobile belt are briefly described and discussed.