The Tugela Terrane, Natal belt: Kibaran magmatism and tectonism along the southeast margin of the Kaapvaal Craton

Abstract

Research Article| March 01, 2002 The Tugela Terrane, Natal belt: Kibaran magmatism and tectonism along the southeast margin of the Kaapvaal Craton S.T. Johnston; S.T. Johnston School of Earth and Ocean Science, University of Victoria, PO Box 3055, STN CSC Victoria, British Columbia, Canada, V8W 3P6, e-mail: [e-mail] Search for other works by this author on: GSW Google Scholar S. McCourt; S. McCourt Department of Geology, University of Durban-Westville, Private Bag X54001, Durban, 4000, South Africa Search for other works by this author on: GSW Google Scholar A. Bisnath; A. Bisnath Department of Geology, University of Durban-Westville, Private Bag X54001, Durban, 4000, South Africa Search for other works by this author on: GSW Google Scholar A. A. Mitchell A. A. Mitchell Department of Geology, University of Durban-Westville, Private Bag X54001, Durban, 4000, South Africa Search for other works by this author on: GSW Google Scholar South African Journal of Geology (2002) 105 (1): 1–13. https://doi.org/10.2113/1050001 Article history first online: 07 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation S.T. Johnston, S. McCourt, A. Bisnath, A. A. Mitchell; The Tugela Terrane, Natal belt: Kibaran magmatism and tectonism along the southeast margin of the Kaapvaal Craton. South African Journal of Geology 2002;; 105 (1): 1–13. doi: https://doi.org/10.2113/1050001 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract This paper is a preliminary report on the geology of the Mandleni tectonostratigraphic package (MTP) part of the Tugela terrane, the northernmost element of the Natal belt in southeastern Africa. The Dondwana gneiss unit, a metamorphosed bimodal magmatic sequence comprising feldspathic gneiss, with lesser amounts of amphibolite, underlies much of the MTP. All primary structures in these rocks have been obliterated during post-depositional metamorphism and deformation. Fabrics attributable to the oldest recognised tectonic event (D1) have largely been overprinted during subsequent deformation. D2 was characterised by syn-kinematic high-pressure (P>9 kbar) granulite facies metamorphism. The dominant S2 planar fabric is a penetrative gneissic foliation that parallels lithological contacts. It is defined by colour and compositional banding, and by parallelism of coarsely crystalline mineral grains. D3 tectonism produced asymmetric north-verging folds, faults and shear zones, which accommodated overthrusting of the MTP onto the Kaapvaal craton. Plagioclase ± biotite mantles on garnet developed at this time and are attributable to uplift of the MTP from the mid- to deep-crustal levels established during D2. Ultramafic rocks (the Evuleka ultramafics) tectonically interleaved with the Dondwana gneiss unit during D3, consist of talc schist, and massive serpentinite with disseminated chromite and magnetite. These ultramafic rocks are interpreted as altered and sheared mantle or cumulate from the lower portion of an ophiolite sequence. Granitoid magmatism associated with D3 is related to subduction beneath the MTP. This subduction led to basin-closure and emplacement of the MTP onto the Kaapvaal craton. The final tectonic event (D4) produced broad open south-plunging folds and sinistral shear zones. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.