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dc.contributor.authorFriedl, G.
dc.contributor.authorCooke, R.
dc.contributor.authorFinger, F.
dc.contributor.authorMcNaughton, Neal
dc.contributor.authorFletcher, Ian
dc.date.accessioned2017-01-30T11:34:55Z
dc.date.available2017-01-30T11:34:55Z
dc.date.created2012-03-04T20:00:45Z
dc.date.issued2011
dc.identifier.citationFriedl, Gertrude and Cooke, Rob A. and Finger, Freidrich and McNaughton, Neal J. and Fletcher, Ian R. 2011. Timing of Variscan HP-HT metamorphism in the Moldanubian Zone of the Bohemian Massif: U-Pb SHRIMP dating on multiply zoned zircons from a granulite from the Dunkelsteiner Wald Massif, Lower Austria. Mineralogy and Petrology. 102 (1-4): pp. 63-75.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/13118
dc.identifier.doi10.1007/s00710-011-0162-x
dc.description.abstract

In an attempt to better constrain the timing of Variscan HP-HT metamorphism in the SE Bohemian Massif we have dated zoned zircons from a garnet-kyanite granulite of granitic composition from the Dunkelsteiner Wald Massif, Lower Austria, by means of sensitive high-resolution ion microprobe (SHRIMP) technique. In order to combine isotopic information with crystal growth textures, CL and BSE images were systematically taken from the dated zircons. A characteristic threefold concentric zoning was found in many zircons. This involves pre-Variscan protolithic cores followed by two distinct metamorphic/anatectic overgrowth shells of Variscan age. The inner overgrowth shell is characterized by a weak CL but bright BSE signal, and yields high contents of uranium (0.1 to 0.2 wt.%). A pooled U-Pb Concordia age for this zone is 342.0 ± 3.0 Ma (n = 11, MSWD = 0.12). The second, outer, overgrowth shell is always bright in the CL image, dark in the BSE image, and has generally low uranium contents (mostly <500 ppm). A pooled U-Pb Concordia age for this zone is 337.1 ± 2.7 Ma (n = 11, MSWD = 0.22). These results imply that the Variscan HT crystallisation history of the Moldanubian granulites took place over a period of a few million years and was not an extremely rapid subduction-exhumation process.SHRIMP measurements in the protolithic cores yield a cluster of (sub)concordant ages between ∼390 and 460 Ma and a few outliers at higher ages mostly represented by cores in cores. Core domains, which are large, homogeneous and with undisturbed igneous oscillatory zoning, yielded preferentially ages between 430 and 460 Ma. We therefore consider that granitic protolith formation took place at that time. The still older inner cores are interpreted as inherited into the granitic melt.

dc.publisherSpringer
dc.subjectDunkelsteiner Wald Massif
dc.subjectSHRIMP
dc.subjectgranitic protolith formation
dc.subjectconcentric zoning
dc.subjectzircon
dc.subjectVariscan
dc.subjectCL
dc.subjectU-Pb Concordia age
dc.titleTiming of Variscan HP-HT metamorphism in the Moldanubian Zone of the Bohemian Massif: U-Pb SHRIMP dating on multiply zoned zircons from a granulite from the Dunkelsteiner Wald Massif, Lower Austria
dc.typeJournal Article
dcterms.source.volume102
dcterms.source.startPage63
dcterms.source.endPage75
dcterms.source.issn0930-0708
dcterms.source.titleMineralogy and Petrology
curtin.departmentJohn de Laeter Centre for Mass Spectrometry (COE)
curtin.accessStatusFulltext not available


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