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dc.contributor.authorMun, Yulia
dc.contributor.authorStrmic Palinkas, Sabina
dc.contributor.authorKullerud, Kåre
dc.contributor.authorNilsen, Kjell S.
dc.contributor.authorNeufeld, Kai
dc.contributor.authorBekker, Andrey
dc.date.accessioned2020-12-15T13:06:03Z
dc.date.available2020-12-15T13:06:03Z
dc.date.issued2020-10-13
dc.description.abstractThe Palaeoproterozoic greenstone belts of Fennoscandia are metamorphosed and deformed volcanic and sedimentary rocks that formed in basins with a high base-metal ore potential. One of these, the Repparfjord Tectonic Window (RTW), is exposed in the Caledonides of northern Norway and contains several sediment-hosted Cu deposits including Nussir and Ulveryggen. The RTW is composed of mafic metavolcanic rocks (metabasalts, volcanoclastic metabreccia and metatuffite) intercalated with carbonate-siliciclastic sedimentary rocks (dolomitic marble, metasandstone to metapelite). This succession was deformed and metamorphosed up to greenschist to lower amphibolite facies during the Svecofennian Orogeny (c. 1.84 Ga). The Cu-mineralisation at the Nussir deposit is hosted by a dolomitic marble. It occurs mostly in the form of quartz-carbonate veins with chalcopyrite, bornite, chalcocite and covellite as the main ore minerals. In contrast, the Ulveryggen mineralisation is predominantly disseminated within a metasiliciclastic succession and dominated by chalcopyrite, bornite, chalcocite, covellite and neodigenite.<p> <p>Mineralogical, geochemical, stable isotope and fluid-inclusion studies provide insights into the evolution of the Cu-bearing fluids. A wide range in homogenisation temperatures (135–350°C at the Nussir deposit and 102–520°C at the Ulveryggen deposit) and fluid-inclusion salinities (from 0.35 up to 36 wt.% NaCl equivalents) suggest an evolving system with brines developed by subsurface evaporite dissolution. Fluid-inclusion and Cu-sphalerite geothermometry data constrain the temperature-pressure conditions of the Cu mineralisation in the Nussir deposit at 330–340°C and 1.1–2.7 kbars. High salinities at relatively high temperatures within the ore-bearing fluids imply that Cu was transported predominantly by Cu-chloride complexes. The interaction of ore-bearing fluids with carbonate-rich host lithologies is proposed as the main mechanism for deposition of the Cu mineralisation at Nussir. In contrast, at the Ulveryggen deposit the mineralisation was mostly controlled by dilution and cooling when ore-bearing fluids mixed with groundwaters. Locally, reaction of Cu-bearing fluids with sediment-hosted pyrite might also have triggered copper precipitation. Similar ranges of δ<sup>13</sup>C (- 0.9 to + 2.9‰ V-PDB) and δ<sup>18</sup>O (- 18.3 to - 15.9‰ V-PDB) values in carbonates from ore-bearing veins and underlying host dolomitic marbles reflect a carbonate rock-buffered system without a significant contribution of magmatic or hydrothermal CO2.en_US
dc.identifier.citationMun Y, Strmic Palinkas S, Kullerud K, Nilsen, Neufeld K, Bekker A. Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway. Norwegian Journal of Geology. 2020;100(202011)en_US
dc.identifier.cristinIDFRIDAID 1850269
dc.identifier.doi10.17850/njg100-2-5
dc.identifier.issn2387-5844
dc.identifier.issn2387-5852
dc.identifier.urihttps://hdl.handle.net/10037/20062
dc.language.isoengen_US
dc.publisherNorsk Geologisk Foreningen_US
dc.relation.journalNorwegian Journal of Geology
dc.relation.projectIDTroms Fylkeskommune: RDA12/167en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2020 The Author(s)en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450en_US
dc.titleEvolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norwayen_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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