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U-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa: refining the duration of Karoo volcanism

Riley, Thomas; Millar, Ian L; Watkeys, M K; Curtis, Michael L; Leat, P T; Klausen, M B; Fanning, Christopher

Description

U-Pb SHRIMP ages are reported for three rhyolite flows from the Lebombo rift region of the Karoo volcanic province. Two flows are interbedded with the Sabic River Basalt Formation and a third sample is from the overlying rhyolitic Jozini Formation. The interbedded rhyolites yield ages of 182.0 ± 2.1 and 179.9 ± 1.8 Ma, whilst the overlying Jozini Formation rhyolite yields an age of 182.1 ± 2.9 Ma. Combined with existing 40Ar/39 Ar geochronology, the new SHRIMP data fine-tunes the chronology of...[Show more]

dc.contributor.authorRiley, Thomas
dc.contributor.authorMillar, Ian L
dc.contributor.authorWatkeys, M K
dc.contributor.authorCurtis, Michael L
dc.contributor.authorLeat, P T
dc.contributor.authorKlausen, M B
dc.contributor.authorFanning, Christopher
dc.date.accessioned2015-12-13T22:49:01Z
dc.date.available2015-12-13T22:49:01Z
dc.identifier.issn0016-7649
dc.identifier.urihttp://hdl.handle.net/1885/80340
dc.description.abstractU-Pb SHRIMP ages are reported for three rhyolite flows from the Lebombo rift region of the Karoo volcanic province. Two flows are interbedded with the Sabic River Basalt Formation and a third sample is from the overlying rhyolitic Jozini Formation. The interbedded rhyolites yield ages of 182.0 ± 2.1 and 179.9 ± 1.8 Ma, whilst the overlying Jozini Formation rhyolite yields an age of 182.1 ± 2.9 Ma. Combined with existing 40Ar/39 Ar geochronology, the new SHRIMP data fine-tunes the chronology of the Karoo volcanic province and indicates the 12 km succession of volcanic rocks in the Lebombo rift were erupted in 1-2 million years and lends considerable support to the links between the Pleinsbachian-Toarcian extinction event and the global environmental impact of Karoo volcanism.
dc.publisherGeological Society of London
dc.sourceJournal of the Geological Society
dc.subjectKeywords: flood basalt; geochronology; Jurassic; mass extinction; SHRIMP dating; volcanism; Africa; Karoo Basin; South Africa; Southern Africa; Sub-Saharan Africa Flood basalts; Karoo; Lemombo rhyolites; Rhyolites; U-Pb
dc.titleU-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa: refining the duration of Karoo volcanism
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume161
dc.date.issued2004
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationMigratedxPub8610
local.type.statusPublished Version
local.contributor.affiliationRiley, Thomas, University of Western Australia
local.contributor.affiliationMillar, Ian L, Natural Environment Research Council
local.contributor.affiliationWatkeys, M K, University of Natal
local.contributor.affiliationCurtis, Michael L, Natural Environment Research Council
local.contributor.affiliationLeat, P T, Natural Environment Research Council
local.contributor.affiliationKlausen, M B, University of Natal
local.contributor.affiliationFanning, Christopher, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.startpage547
local.bibliographicCitation.lastpage550
local.identifier.doi10.1144/0016-764903-181
dc.date.updated2015-12-11T10:32:04Z
local.identifier.scopusID2-s2.0-3142714010
CollectionsANU Research Publications

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