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dc.contributor.authorWielens, J.B.W.
dc.contributor.authorVerschure, R.H.
dc.contributor.authorVerdurmen, E.A.Th.
dc.contributor.authorPriem, H.N.A.
dc.contributor.authorHebeda, E.H.
dc.contributor.authorBoelrijk, N.A.I.M.
dc.contributor.authorAndriessen, P.A.M.
dc.coverage.spatialSANDNES
dc.coverage.spatial12121 Høle
dc.coverage.spatial12122 Bjerkreim
dc.coverage.spatial13121 Øvre Sirdal
dc.coverage.spatial13122 Tonstad
dc.coverage.spatialBJERKREIM
dc.coverage.spatialLUND
dc.coverage.spatialSIRDAL
dc.coverage.spatial13123 Ørsdalsvatnet
dc.coverage.spatial13124 Frafjord
dc.coverage.spatialGJESDAL
dc.date.accessioned2020-08-26T13:19:45Z
dc.date.available2020-08-26T13:19:45Z
dc.date.issued1980
dc.identifier.urihttps://hdl.handle.net/11250/2675093
dc.description.abstractA new series of isotopic age data is reported from the high-grade metamorphic Precambrian in S.W. Norway, mainly from the Sirdal-Ørsdal area. U-Pb investigations on suites of zircons from three augen gneisses and a pyroxene syenite produce discordias with upper intercepts between 1070 and 1030 Ma; these ages are assigned to the highest-grade phase of Sveconorwegian metamorphism, M2, induced by the intrusion of the older part of the Bjerkreim-Sokndal lopolith. Some zirkon fractions from antoher pyroxene syenite and a garnetiferous migmatite contain an inheritance of old radiogenic lead, but no conclusions are possible regarding the age of the older component. The lower intercepts of the discordia trajectories are interpreted as reflecting episodic loss of radiogenic lead in the Palaezoic, probably in relation to nearby belt of Caledonian orogenesis and \/or post-orogenic uplift; the lead-loss event is tentatively correlated with M4 phase of incipient very-low-grade metamorphism.
dc.language.isoeng
dc.relation.ispartofseriesNGU (359)
dc.rightsNavngivelse 4.0 Internasjonal
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/deed.no
dc.subjectOMDANNET BERGART
dc.subjectGEOKRONOLOGI
dc.subjectISOTOPSTRATIGRAFI
dc.subjectPREKAMBRIUM
dc.titleIsotope geochronology in the high-grade metamorphic Precambrian of southwestern Norway: new data and reinterpretation.
dc.typeJournal article
dc.description.localcode35995
dc.source.pagenumber1-30


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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal