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New PGE and Re/Os-isotope data from lower crustal sections of the Vredefort Dome and a reinterpretation of its "crust on edge" profile

2004; Geological Society of South Africa; Volume: 107; Issue: 1-2 Linguagem: Inglês

10.2113/107.1-2.173

1996-8590

Rodger J. Hart, Iain McDonald, M. Tredoux, Maarten J. de Wit, Richard W. Carlson, M. A. G. Andreoli, D. E. Moser, Lewis D. Ashwal,

Geological and Geophysical Studies

Research Article| June 01, 2004 New PGE and Re/Os-isotope data from lower crustal sections of the Vredefort Dome and a reinterpretation of its "crust on edge" profile Rodger J. Hart; Rodger J. Hart Schonland Research Centre, University of the Witwatersrand, P.O. Wits 2050, South Africa, email: hart@schonlan.src.wits.ac.za Search for other works by this author on: GSW Google Scholar Iain McDonald; Iain McDonald Department of Earth Sciences, Cardiff University, P.O. Box 914, Cardiff CF1 3YE, email: iain@earth.cf.ac.uk Search for other works by this author on: GSW Google Scholar Marian Tredoux; Marian Tredoux Department of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa, email: mtd@geology.uct.ac.za, maarten@cigc.uct.ac.za Search for other works by this author on: GSW Google Scholar Maarten J. de Wit; Maarten J. de Wit Department of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa, email: mtd@geology.uct.ac.za, maarten@cigc.uct.ac.za Search for other works by this author on: GSW Google Scholar Richard W. Carlson; Richard W. Carlson Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, D.C., 20015, USA., email: carlson@dtm.ciw.edu Search for other works by this author on: GSW Google Scholar Marco Andreoli; Marco Andreoli South African Nuclear Energy Corporation, P. O. Box 582, Pretoria, 0001, South Africa, email: marco@necsa.co.za Search for other works by this author on: GSW Google Scholar Desmond E. Moser; Desmond E. Moser Geology and Geophysics Department., University of Utah 135S 1460E Salt Lake City, UT 84112-0111 USA, email: demoser@mines.utah.edu Search for other works by this author on: GSW Google Scholar Lewis D. Ashwal Lewis D. Ashwal School of Geosciences, University of the Witwatersrand, Private bag 3, Wits 2050, South Africa, email: ashwall@geosciences.wits.ac.za Search for other works by this author on: GSW Google Scholar Author and Article Information Rodger J. Hart Schonland Research Centre, University of the Witwatersrand, P.O. Wits 2050, South Africa, email: hart@schonlan.src.wits.ac.za Iain McDonald Department of Earth Sciences, Cardiff University, P.O. Box 914, Cardiff CF1 3YE, email: iain@earth.cf.ac.uk Marian Tredoux Department of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa, email: mtd@geology.uct.ac.za, maarten@cigc.uct.ac.za Maarten J. de Wit Department of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa, email: mtd@geology.uct.ac.za, maarten@cigc.uct.ac.za Richard W. Carlson Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, D.C., 20015, USA., email: carlson@dtm.ciw.edu Marco Andreoli South African Nuclear Energy Corporation, P. O. Box 582, Pretoria, 0001, South Africa, email: marco@necsa.co.za Desmond E. Moser Geology and Geophysics Department., University of Utah 135S 1460E Salt Lake City, UT 84112-0111 USA, email: demoser@mines.utah.edu Lewis D. Ashwal School of Geosciences, University of the Witwatersrand, Private bag 3, Wits 2050, South Africa, email: ashwall@geosciences.wits.ac.za Publisher: Geological Society of South Africa First Online: 07 Mar 2017 Online ISSN: 1996-8590 Print ISSN: 1012-0750 © 2003 Geological Society of South Africa South African Journal of Geology (2004) 107 (1-2): 173–184. https://doi.org/10.2113/107.1-2.173 Article history First Online: 07 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Rodger J. Hart, Iain McDonald, Marian Tredoux, Maarten J. de Wit, Richard W. Carlson, Marco Andreoli, Desmond E. Moser, Lewis D. Ashwal; New PGE and Re/Os-isotope data from lower crustal sections of the Vredefort Dome and a reinterpretation of its "crust on edge" profile. South African Journal of Geology 2004;; 107 (1-2): 173–184. doi: https://doi.org/10.2113/107.1-2.173 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 Granulites exposed in the core of the Vredefort Dome are generally thought to represent components of the Archean middle crust of the central Kaapvaal Craton. These rocks were exhumed from depths of at least 20 km following an ~2.02 Ga meteorite impact event, exposing a "crust on edge" section believed to represent a continuous magmatically-differentiated sequence from upper crust possibly down to Moho. Platinum group element concentrations suggest that mafic and ultramafic enclaves in the lower most sections are fragments of greenstone belt material metamorphosed at granulite grade. Re/Os isotopic data are consistent with previously published U-Pb zircon data, which suggest that the mafic and ultramafic rocks have a primary age of ~3.5 Ga and were metamorphosed to granulite grade at ~3.1 Ga. However, near the core of the Vredefort Dome across a major shear zone, other ~3.5 Ga greenstone belt remnants are at distinctly lower metamorphic grade. The juxtaposition of mafic-ultramafic rocks with a different metamorphic history in the core of the Vredefort structure requires a modified "crust on edge" model that incorporates tectonic stacking of different crustal segments at ~3.1 Ga. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.