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Comparative use of TIMS and SHRIMP for U-Pb zircon dating of A-type granites and mafic tholeiitic layered complexes and dykes from the Corsican Batholith (France)

Cocherie, Alain; Rossi, Philippe; Fanning, Christopher; Guerrot, Catherine

Description

The Corsica-Sardinia batholith in the southern realm of the Hercynian belt of Europe shows evidence for gravitational collapse of this part of the mountain belt, causing major felsic and mafic magmatism. The latest intrusions are composed of leucomonzogranite and late metaluminous and alkaline granite, associated with tholeiitic layered complexes and dykes. Three dating methods on zircon (Pb-evaporation, ID-TIMS and SHRIMP) were used to unravel the chronology of these felsic and mafic rocks....[Show more]

dc.contributor.authorCocherie, Alain
dc.contributor.authorRossi, Philippe
dc.contributor.authorFanning, Christopher
dc.contributor.authorGuerrot, Catherine
dc.date.accessioned2015-12-13T23:00:19Z
dc.identifier.issn0024-4937
dc.identifier.urihttp://hdl.handle.net/1885/84066
dc.description.abstractThe Corsica-Sardinia batholith in the southern realm of the Hercynian belt of Europe shows evidence for gravitational collapse of this part of the mountain belt, causing major felsic and mafic magmatism. The latest intrusions are composed of leucomonzogranite and late metaluminous and alkaline granite, associated with tholeiitic layered complexes and dykes. Three dating methods on zircon (Pb-evaporation, ID-TIMS and SHRIMP) were used to unravel the chronology of these felsic and mafic rocks. Dating of zircons by the conventional U-Pb method, using TIMS after zircon dissolution, achieved an analytical uncertainty of 1 Ma for favourable cases. The TIMS Pb-evaporation technique resulted in ages with an uncertainty range of 4 to 8 Ma. After 15 to 20 analyses with the SHRIMP method, a precision ranging from 2 to 5 Ma was obtained (all at 2σ). The three methods applied to the same zircon population extracted from four A-type granites, show that the uncertainty ranges within 2-5 Ma according to the sample. This error seems to correspond to the real geochronological uncertainty that can be achieved. The results obtained show that all six tested alkaline granites were emplaced during a very short interval of about 3-5 Ma at about 288 Ma, almost contemporaneous with the leucomonzogranite emplacement (291-287 Ma) that ended the batholith formation. In addition, there is no significant gap with the age of emplacement of the mafic tholeiitic magmatism (around 286 Ma) crosscutting the "A-type" granites. The late alkaline granites definitely do not show up here as precursors of the Tethyan rifting that began at about 170 Ma, i.e. some 100 Ma after their emplacement. It is thus necessary to examine if alternative hypotheses to the anorogenic model of the A-type Younger Granite province better fit the new geochronological data. A model involving depleted continental-crust derived magma should be compatible with the timing and geodynamical constraints as far as isotopic data are concerned.
dc.publisherElsevier
dc.sourceLithos
dc.subjectKeywords: batholith; comparative study; dating method; geochronology; Hercynian orogeny; Corse; Eastern Hemisphere; Eurasia; Europe; France; Western Europe; World A-type granite; Corsica; Geochronology; Zircon
dc.titleComparative use of TIMS and SHRIMP for U-Pb zircon dating of A-type granites and mafic tholeiitic layered complexes and dykes from the Corsican Batholith (France)
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume82
dc.date.issued2005
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationMigratedxPub12327
local.type.statusPublished Version
local.contributor.affiliationCocherie, Alain, Bureau de Recherche Geologique et Miniere
local.contributor.affiliationRossi, Philippe, Bureau de Recherche Geologique et Miniere
local.contributor.affiliationFanning, Christopher, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationGuerrot, Catherine, Bureau de Recherche Geologique et Miniere
local.description.embargo2037-12-31
local.bibliographicCitation.startpage185
local.bibliographicCitation.lastpage219
local.identifier.doi10.1016/j.lithos.2004.12.016
dc.date.updated2015-12-12T07:33:09Z
local.identifier.scopusID2-s2.0-18244371058
CollectionsANU Research Publications

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