The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System
The modern concepts of magmatic plumbing systems have evolved from simple models of melt-dominated crustal magma chambers to magmatic systems that span the continental crust. The geochemistry of these systems is challenging to model numerically because of a complex polybaric and multiphase evolution...
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Oxford University Press
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Online Access: | https://hdl.handle.net/11250/2988115 https://doi.org/10.1093/petrology/egac008 |
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ftntnutrondheimi:oai:ntnuopen.ntnu.no:11250/2988115 2023-05-15T15:13:02+02:00 The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System Orvik, Alf Andre Slagstad, Trond Hansen, Harald Nilsson, Lars Petter Sørensen, Bjørn Eske 2022 application/pdf https://hdl.handle.net/11250/2988115 https://doi.org/10.1093/petrology/egac008 eng eng Oxford University Press Norges forskningsråd: 269842 Norges teknisk-naturvitenskapelige universitet: 81771445 Journal of Petrology. 2022, 63 (3), 1-28. urn:issn:0022-3530 https://hdl.handle.net/11250/2988115 https://doi.org/10.1093/petrology/egac008 cristin:2011985 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no CC-BY 1-28 63 Journal of Petrology 3 Peer reviewed Journal article 2022 ftntnutrondheimi https://doi.org/10.1093/petrology/egac008 2022-04-13T22:39:35Z The modern concepts of magmatic plumbing systems have evolved from simple models of melt-dominated crustal magma chambers to magmatic systems that span the continental crust. The geochemistry of these systems is challenging to model numerically because of a complex polybaric and multiphase evolution, which is not well described by mathematic end-member formulas. We propose that a recent modelling tool, the Magma Chamber Simulator (MCS), can reveal part of the petrological complexities of such systems. The MCS numerically models phase equilibria, mineral chemistry and major and trace elements in multicomponent–multiphase systems by finding the extremes of the appropriate state functions. This study presents new petrographical and geochemical data from the Palaeoproterozoic Gallujavri ultramafic intrusion in the Karasjok Greenstone Belt, Arctic Norway. Our data indicate that (1) the intrusion is affected by crustal assimilation, (2) phase equilibria require polybaric crystallisation and (3) spinel compositions are similar to sub-volcanic intrusions of continental flood basalt provinces. We utilise the MCS to simulate the petrogenesis of the intrusion and test the model by comparing it against our reported petrological and geochemical data. Our modelling shows that the parental magma of the intrusion is consistent with coeval Karasjok-type komatiites observed at various places throughout the greenstone belt. First, the komatiitic primary magma intruded Archaean lower crust (c. 700 MPa), where fractionation and assimilation resulted in a hybrid melt. Second, the hybrid melt migrated and accumulated in a mid-crustal magma chamber (c. 400 MPa), where it continued to fractionate and assimilate while remaining open to recharge of mantle-derived komatiitic melts, forming the Gallujavri intrusion. We interpret the Gallujavri intrusion as part of a Palaeoproterozoic trans-crustal magma plumbing system, with many similarities to other Fennoscandian ultramafic-mafic layered intrusions. publishedVersion Article in Journal/Newspaper Arctic Fennoscandian Karasjok NTNU Open Archive (Norwegian University of Science and Technology) Arctic Gallujavri ENVELOPE(25.375,25.375,69.629,69.629) Karasjok ENVELOPE(25.519,25.519,69.472,69.472) Norway Journal of Petrology 63 3 |
institution |
Open Polar |
collection |
NTNU Open Archive (Norwegian University of Science and Technology) |
op_collection_id |
ftntnutrondheimi |
language |
English |
description |
The modern concepts of magmatic plumbing systems have evolved from simple models of melt-dominated crustal magma chambers to magmatic systems that span the continental crust. The geochemistry of these systems is challenging to model numerically because of a complex polybaric and multiphase evolution, which is not well described by mathematic end-member formulas. We propose that a recent modelling tool, the Magma Chamber Simulator (MCS), can reveal part of the petrological complexities of such systems. The MCS numerically models phase equilibria, mineral chemistry and major and trace elements in multicomponent–multiphase systems by finding the extremes of the appropriate state functions. This study presents new petrographical and geochemical data from the Palaeoproterozoic Gallujavri ultramafic intrusion in the Karasjok Greenstone Belt, Arctic Norway. Our data indicate that (1) the intrusion is affected by crustal assimilation, (2) phase equilibria require polybaric crystallisation and (3) spinel compositions are similar to sub-volcanic intrusions of continental flood basalt provinces. We utilise the MCS to simulate the petrogenesis of the intrusion and test the model by comparing it against our reported petrological and geochemical data. Our modelling shows that the parental magma of the intrusion is consistent with coeval Karasjok-type komatiites observed at various places throughout the greenstone belt. First, the komatiitic primary magma intruded Archaean lower crust (c. 700 MPa), where fractionation and assimilation resulted in a hybrid melt. Second, the hybrid melt migrated and accumulated in a mid-crustal magma chamber (c. 400 MPa), where it continued to fractionate and assimilate while remaining open to recharge of mantle-derived komatiitic melts, forming the Gallujavri intrusion. We interpret the Gallujavri intrusion as part of a Palaeoproterozoic trans-crustal magma plumbing system, with many similarities to other Fennoscandian ultramafic-mafic layered intrusions. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Orvik, Alf Andre Slagstad, Trond Hansen, Harald Nilsson, Lars Petter Sørensen, Bjørn Eske |
spellingShingle |
Orvik, Alf Andre Slagstad, Trond Hansen, Harald Nilsson, Lars Petter Sørensen, Bjørn Eske The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System |
author_facet |
Orvik, Alf Andre Slagstad, Trond Hansen, Harald Nilsson, Lars Petter Sørensen, Bjørn Eske |
author_sort |
Orvik, Alf Andre |
title |
The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System |
title_short |
The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System |
title_full |
The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System |
title_fullStr |
The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System |
title_full_unstemmed |
The Palaeoproterozoic Gallujavri Ultramafic Intrusion, Karasjok Greenstone Belt; Petrogenesis of a Trans-Crustal Magma System |
title_sort |
palaeoproterozoic gallujavri ultramafic intrusion, karasjok greenstone belt; petrogenesis of a trans-crustal magma system |
publisher |
Oxford University Press |
publishDate |
2022 |
url |
https://hdl.handle.net/11250/2988115 https://doi.org/10.1093/petrology/egac008 |
long_lat |
ENVELOPE(25.375,25.375,69.629,69.629) ENVELOPE(25.519,25.519,69.472,69.472) |
geographic |
Arctic Gallujavri Karasjok Norway |
geographic_facet |
Arctic Gallujavri Karasjok Norway |
genre |
Arctic Fennoscandian Karasjok |
genre_facet |
Arctic Fennoscandian Karasjok |
op_source |
1-28 63 Journal of Petrology 3 |
op_relation |
Norges forskningsråd: 269842 Norges teknisk-naturvitenskapelige universitet: 81771445 Journal of Petrology. 2022, 63 (3), 1-28. urn:issn:0022-3530 https://hdl.handle.net/11250/2988115 https://doi.org/10.1093/petrology/egac008 cristin:2011985 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1093/petrology/egac008 |
container_title |
Journal of Petrology |
container_volume |
63 |
container_issue |
3 |
_version_ |
1766343641433899008 |