40Ar/39Ar age constraints on low-grade metamorphism and cleavage development in the Transvaal Supergroup (central Kaapvaal craton, South Africa): implications for the tectonic setting of the Bushveld Igneous Complex

Research Article| September 01, 2006 40Ar/39Ar age constraints on low-grade metamorphism and cleavage development in the Transvaal Supergroup (central Kaapvaal craton, South Africa): implications for the tectonic setting of the Bushveld Igneous Complex Paul Alexandre; Paul Alexandre SUERC, Rankine Avenue, Technology Park, East Kilbride, G75 0QF, United Kingdom, e-mail: P.Alexandre@suerc.gla.ac.uk Search for other works by this author on: GSW Google Scholar Marco A.G. Andreoli; Marco A.G. Andreoli South African Nuclear Energy Corporation, P.O. Box 582, Pretoria 0001, South Africa, School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa, e-mail: marco@necsa.co.za Search for other works by this author on: GSW Google Scholar Antony Jamison; Antony Jamison School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa e-mail: tjamison@hot.co.za; gibsonr@geosciences.wits.ac.za Search for other works by this author on: GSW Google Scholar Roger L. Gibson Roger L. Gibson School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa e-mail: tjamison@hot.co.za; gibsonr@geosciences.wits.ac.za Search for other works by this author on: GSW Google Scholar South African Journal of Geology (2006) 109 (3): 393–410. https://doi.org/10.2113/gssajg.109.3.393 Article history first online: 09 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 Paul Alexandre, Marco A.G. Andreoli, Antony Jamison, Roger L. Gibson; 40Ar/39Ar age constraints on low-grade metamorphism and cleavage development in the Transvaal Supergroup (central Kaapvaal craton, South Africa): implications for the tectonic setting of the Bushveld Igneous Complex. South African Journal of Geology 2006;; 109 (3): 393–410. doi: https://doi.org/10.2113/gssajg.109.3.393 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 Rocks of the Palaeoproterozoic Transvaal Supergroup, situated between the Bushveld Igneous Complex and the Vredefort Impact Structure in the central parts of the Kaapvaal craton (South Africa), experienced a regional low-grade metamorphism synchronous with brittle–ductile deformation that formed small- to medium-scale folds, cleavages, monoclines and thrusts in the dolomites, slates, and phyllites. Single-grain 40Ar/39Ar step-heating laser probe dating of synkinematic white mica from the phyllites indicates ages of ~2.15 Ga and 2042.1 ± 2.9 Ma (plateaus and pseudo-plateaus, as well as cumulative probability statistics). These ages are clearly distinct from the emplacement age of the Bushveld Igneous Complex (~2.06 Ga) and from the Vredefort impact event (~2.02 Ga), both of which have previously been suggested as possible causes of the deformation. The new data suggest that at ~2.04 Ga, the rocks of the Transvaal Supergroup in the central craton were part of a more extensive fold-and-thrust belt, named here the Transvaalide fold-and-thrust belt. While it is difficult to explain the significance of the ~2.15 Ga ages, the ~2.04 Ga event may be related to orogenic activity along the margins of the Kaapvaal craton at this time. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.