New U-Pb SHRIMP zircon age for the Schurwedraai alkali granite: Implications for pre-impact development of the Vredefort Dome and extent of Bushveld magmatism, South Africa
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Graham, IT; De Waal, S.A.; Armstrong, Richard
Description
The Schurwedraai alkali granite is one of a number of prominent ultramafic-mafic and felsic intrusions in the Neoarchaean to Palaeoproterozoic sub-vertical supracrustal collar rocks of the Vredefort Dome, South Africa. The alkali granite intruded the Neoarchaean Witwatersrand Supergroup and has a peralkaline to peraluminous composition. A new zircon SHRIMP crystallization age of 2052 ± 14 Ma for the Schurwedraai alkali granite places it statistically before the Vredefort impact event at 2023 ±...[Show more]
dc.contributor.author | Graham, IT | |
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dc.contributor.author | De Waal, S.A. | |
dc.contributor.author | Armstrong, Richard | |
dc.date.accessioned | 2015-12-13T22:43:16Z | |
dc.identifier.issn | 0899-5362 | |
dc.identifier.uri | http://hdl.handle.net/1885/79128 | |
dc.description.abstract | The Schurwedraai alkali granite is one of a number of prominent ultramafic-mafic and felsic intrusions in the Neoarchaean to Palaeoproterozoic sub-vertical supracrustal collar rocks of the Vredefort Dome, South Africa. The alkali granite intruded the Neoarchaean Witwatersrand Supergroup and has a peralkaline to peraluminous composition. A new zircon SHRIMP crystallization age of 2052 ± 14 Ma for the Schurwedraai alkali granite places it statistically before the Vredefort impact event at 2023 ± 4 Ma and within the accepted emplacement interval of 2050-2060 Ma of the Bushveld magmatic event. The presence of the alkali granite and associated small ultramafic-mafic intrusions in the Vredefort collar rocks extends the southern extremity of Bushveld-related intrusions to some 120 km south of Johannesburg and about 150 km south of the current outcrop area of the Bushveld Complex. The combined effect of these ultramafic-mafic and felsic bodies may have contributed to a pronouncedly steep pre-impact geothermal gradient in the Vredefort area, and to the amphibolite-grade metamorphism observed in the supracrustal collar rocks of the Vredefort Dome. | |
dc.publisher | Pergamon-Elsevier Ltd | |
dc.source | Journal of African Earth Sciences | |
dc.subject | Keywords: alkaline rock; geochronology; granite; Precambrian; Africa; Free State; South Africa; Southern Africa; Sub-Saharan Africa; Vredefort Dome Bushveld; Schurwedraai; SHRIMP; Vredefort; Witwatersrand | |
dc.title | New U-Pb SHRIMP zircon age for the Schurwedraai alkali granite: Implications for pre-impact development of the Vredefort Dome and extent of Bushveld magmatism, South Africa | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.description.refereed | Yes | |
local.identifier.citationvolume | 43 | |
dc.date.issued | 2005 | |
local.identifier.absfor | 040203 - Isotope Geochemistry | |
local.identifier.ariespublication | MigratedxPub7640 | |
local.type.status | Published Version | |
local.contributor.affiliation | Graham, IT, University of Pretoria | |
local.contributor.affiliation | De Waal, S.A., University of Pretoria | |
local.contributor.affiliation | Armstrong, Richard, College of Physical and Mathematical Sciences, ANU | |
local.description.embargo | 2037-12-31 | |
local.bibliographicCitation.startpage | 537 | |
local.bibliographicCitation.lastpage | 548 | |
local.identifier.doi | 10.1016/j.jafrearsci.2005.09.009 | |
dc.date.updated | 2015-12-11T10:11:30Z | |
local.identifier.scopusID | 2-s2.0-30444439713 | |
Collections | ANU Research Publications |
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