| Date | Early Archean ( up to 3.46 Ga) |
|---|---|
| Type | Craton |
TheZimbabwe craton is an area in Southern Africa of ancient continental crust, being a part of the ancient continent of WesternGondwana, with rocks dating back to the earlyArchean Eon, possibly as early as 3.46 billion years ago (Ga.).[1] Thecraton is named after the country ofZimbabwe where the majority of the craton is. The rocks of the Zimbabwe Craton are separated from the rocks of theKaapvaal craton to the southeast by the 250 kilometres (160 mi) wideLimpopo Belt ofgranulitefaciestectonites. The Limpopo belt formed contemporaneously with the Zimbabwe and Kaapvaal cratons, but remained geologically active until much later. It was only in the late Archean, ca. 2.8-2.5 Ga., that the two cratons were stabilized together and that high-grademetamorphism ceased in the Limpopo Belt. North of the Zimbabwe Craton is theZambezi Belt.[2]
The Zimbabwe Craton formed from the suture of two smaller blocks, the Tokwe Segment to the south and the much smaller Rhodesdale Segment (aka Rhodesdale gneiss), to the north. The rocks of these segments have been dated to as early as 3.46 Ga.[1] The Tokwe Segment probably stabilized about 3.3 Ga., and there is evidence that the Rhodesdale Segment stabilized about the same time.[3][4]
The synchroneity and extent of the Tokwe Segment is considered strong evidence supporting a predominantly intra-cratonic origin for the Late Archaeangreenstone belts of Zimbabwe and refuting an arcaccretion origin for the craton.[4]
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