Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway
The 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...
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Norsk Geologisk Forening
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ftunivtroemsoe:oai:munin.uit.no:10037/20062 2023-05-15T16:12:19+02:00 Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway Mun, Yulia Strmic Palinkas, Sabina Kullerud, Kåre Nilsen, Kjell S. Neufeld, Kai Bekker, Andrey 2020-10-13 https://hdl.handle.net/10037/20062 https://doi.org/10.17850/njg100-2-5 eng eng Norsk Geologisk Forening Norwegian Journal of Geology Troms Fylkeskommune: RDA12/167 FRIDAID 1850269 doi:10.17850/njg100-2-5 2387-5844 2387-5852 https://hdl.handle.net/10037/20062 openAccess Copyright 2020 The Author(s) VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 Journal article Tidsskriftartikkel Peer reviewed publishedVersion 2020 ftunivtroemsoe https://doi.org/10.17850/njg100-2-5 2021-06-25T17:57:51Z The 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. 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 13 C (- 0.9 to + 2.9‰ V-PDB) and δ 18 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. Article in Journal/Newspaper Fennoscandia Northern Norway University of Tromsø: Munin Open Research Archive Norway Nussir ENVELOPE(23.535,23.535,70.096,70.096) Repparfjord ENVELOPE(24.550,24.550,70.417,70.417) Ulveryggen ENVELOPE(24.223,24.223,70.434,70.434) Norwegian Journal of Geology |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 |
spellingShingle |
VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 Mun, Yulia Strmic Palinkas, Sabina Kullerud, Kåre Nilsen, Kjell S. Neufeld, Kai Bekker, Andrey Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway |
topic_facet |
VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 |
description |
The 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. 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 13 C (- 0.9 to + 2.9‰ V-PDB) and δ 18 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. |
format |
Article in Journal/Newspaper |
author |
Mun, Yulia Strmic Palinkas, Sabina Kullerud, Kåre Nilsen, Kjell S. Neufeld, Kai Bekker, Andrey |
author_facet |
Mun, Yulia Strmic Palinkas, Sabina Kullerud, Kåre Nilsen, Kjell S. Neufeld, Kai Bekker, Andrey |
author_sort |
Mun, Yulia |
title |
Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway |
title_short |
Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway |
title_full |
Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway |
title_fullStr |
Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway |
title_full_unstemmed |
Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway |
title_sort |
evolution of metal-bearing fluids at the nussir and ulveryggen sediment-hosted cu deposits, repparfjord tectonic window, northern norway |
publisher |
Norsk Geologisk Forening |
publishDate |
2020 |
url |
https://hdl.handle.net/10037/20062 https://doi.org/10.17850/njg100-2-5 |
long_lat |
ENVELOPE(23.535,23.535,70.096,70.096) ENVELOPE(24.550,24.550,70.417,70.417) ENVELOPE(24.223,24.223,70.434,70.434) |
geographic |
Norway Nussir Repparfjord Ulveryggen |
geographic_facet |
Norway Nussir Repparfjord Ulveryggen |
genre |
Fennoscandia Northern Norway |
genre_facet |
Fennoscandia Northern Norway |
op_relation |
Norwegian Journal of Geology Troms Fylkeskommune: RDA12/167 FRIDAID 1850269 doi:10.17850/njg100-2-5 2387-5844 2387-5852 https://hdl.handle.net/10037/20062 |
op_rights |
openAccess Copyright 2020 The Author(s) |
op_doi |
https://doi.org/10.17850/njg100-2-5 |
container_title |
Norwegian Journal of Geology |
_version_ |
1765997607803420672 |