|
Article |
Department of Geology, University of Zimbabwe. PO Box MP 167, Harare, Zimbabwe
The Northern Marginal Zone of the Limpopo Belt in southern Africa comprises a Plutonic Assemblage of granitoids including a distinctive suite of porphyroclastic granites. and a much less abundant Supracrustal Assemblage of metabasites and iron formations. These rocks are at granulite facies above a normal thickness of continental crust. Most of the Plutonic Assemblage are intrusive rocks that crystallized from dry melts from 2800 to 2600 Ma, with a relatively simple thermal history. They may have been derived from partial melting of a mafic source. Some supracrustal rocks have experienced two thermal events at granulite facies.
A reverse-sense shear zone forms the boundary of the Northern Marginal Zone with the Zimbabwe craton. The southern boundary is the Triangle shear zone, which is proven as a continuous structure along a much greater strike length than previously documented. A widespread sub-vertical foliation in the Northern Marginal Zone and the reverse shear zone formed during progressive NNW-SSE shortening. Crustal thickening occurred both magmatically and tectonically in the late Archaean, and was accompanied by synchronous uplift. Protracted magmatism provides a mechanism to incorporate supracrustal rocks into the lower crust, and can explain the occurrence of more than a single thermal event.
Key Words: Archaean • granulites • Limpopo Belt • Zimbabwe
This article has been cited by other articles:
 |
|
 |
|
  M. D. Prendergast Archean Komatiitic Sill-hosted Chromite Deposits in the Zimbabwe Craton Economic Geology, 2008; 103: 981 - 1004. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. G. Blenkinsop and A. F. M. Kisters Steep extrusion of late Archaean granulites in the Northern Marginal Zone, Zimbabwe: evidence for secular change in orogenic style Geological Society, London, Special Publications, 2005; 243: 193 - 204. [Abstract] [PDF]
|
|
|
|
 |
|
 T. G. Blenkinsop, A. Kroner, and V. Chiwara Single stage, late Archaean exhumation of granulites in the Northern Marginal Zone, Limpopo Belt, Zimbabwe, and relevance to gold mineralization at Renco mine South African Journal of Geology, 2004; 107: 377 - 396. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. McCourt, A.B. Kampunzu, Z. Bagai, and R.A. Armstrong The crustal architecture of Archaean terranes in Northeastern Botswana South African Journal of Geology, 2004; 107: 147 - 158. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. S. Buick, I.S. Buick, I.S. Williams, R.L. Gibson, I. Cartwright, and J.A. Miller Carbon and U-Pb evidence for a Palaeoproterozoic crustal component in the Central Zone of the Limpopo Belt, South Africa Journal of the Geological Society, 2003; 160: 601 - 612. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. G. Blenkinsop, T. G. BLENKINSOP, and P. J. TRELOAR Tabular intrusion and folding of the late Archaean Murehwa granite, Zimbabwe, during regional shortening Journal of the Geological Society, 2001; 158: 653 - 664. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. MKWELI, B. KAMBER, and M. BERGER Westward continuation of the craton-Limpopo Belt tectonic break in Zimbabwe and new age constraints on the timing of the thrusting Journal of the Geological Society, 1995; 152: 77 - 83. [Abstract] [PDF]
|
|
|
|
|
|
P. J. Treloar and T. G. Blenkinsop Archaean deformation patterns in Zimbabwe: true indicators of Tibetan-style crustal extrusion or not? Geological Society, London, Special Publications, 1995; 95: 87 - 107. [Abstract] [PDF]
|
|
