Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland
The Isortoq Giant Dykes in the Proterozoic Gardar Province, South Greenland, include the Isortoq South giant dyke and the Isortoq North giant dyke. The fine-grained Fe-Ti-V deposit hosted by the Isortoq South giant dyke, referred to as the Isortoq Fe-Ti-V deposit, is considered a good test site for...
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Geological Survey of Denmark and Greenland
2020
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ftdoajarticles:oai:doaj.org/article:fea711fb34f7447eac3df7f57bb58e51 2023-05-15T16:28:20+02:00 Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland Diogo Rosa Alessandro Sandrin Troels F.D. Nielsen Høgni Vesturklett 2020-08-01T00:00:00Z https://doi.org/10.34194/geusb.v44.4626 https://doaj.org/article/fea711fb34f7447eac3df7f57bb58e51 EN eng Geological Survey of Denmark and Greenland https://geusbulletin.org/index.php/geusb/article/view/4626/11145 https://doaj.org/toc/2597-2154 2597-2154 doi:10.34194/geusb.v44.4626 https://doaj.org/article/fea711fb34f7447eac3df7f57bb58e51 GEUS Bulletin, Vol 44, Iss 0, Pp 1-8 (2020) isortoq fe-ti-v deposit gardar province petrophysics magma chamber troctolite Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 article 2020 ftdoajarticles https://doi.org/10.34194/geusb.v44.4626 2022-12-31T10:18:35Z The Isortoq Giant Dykes in the Proterozoic Gardar Province, South Greenland, include the Isortoq South giant dyke and the Isortoq North giant dyke. The fine-grained Fe-Ti-V deposit hosted by the Isortoq South giant dyke, referred to as the Isortoq Fe-Ti-V deposit, is considered a good test site for the use of magnetic susceptibility for the mapping of ore grades. Here, we test this and show that the Fe, Ti and V distribution is controlled by titanomagnetite disseminated throughout fine-grained troctolite. The deposit displays a clear correlation between magnetic susceptibility and Fe, Ti and V grades in bulk samples of consecutive 2 m sections from 11 drill cores, totalling 2671 m in length. We observe that Fe, Ti and V are almost entirely hosted in titanomagnetite, which controls the magnetic susceptibility. Field measurements of the magnetic susceptibility can thus be considered as a reliable exploration tool for this type of mineralisation. We further consider the origins of the deposit by reconnaissance petrography, mineral and bulk rock chemistry of the large mass of aphanitic Fe-rich troctolite in the Isortoq South giant dyke. We suggest that the deposit may represent the base of a basanitic to trachybasaltic magma chamber, in which Fe-rich immiscible melts accumulated, crystallised and fractionated. The processes suggested here may apply to other giant dykes and intrusions of the Gardar Province. Article in Journal/Newspaper Greenland Isortoq Directory of Open Access Journals: DOAJ Articles Greenland GEUS Bulletin |
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op_collection_id |
ftdoajarticles |
language |
English |
topic |
isortoq fe-ti-v deposit gardar province petrophysics magma chamber troctolite Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
isortoq fe-ti-v deposit gardar province petrophysics magma chamber troctolite Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 Diogo Rosa Alessandro Sandrin Troels F.D. Nielsen Høgni Vesturklett Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland |
topic_facet |
isortoq fe-ti-v deposit gardar province petrophysics magma chamber troctolite Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 |
description |
The Isortoq Giant Dykes in the Proterozoic Gardar Province, South Greenland, include the Isortoq South giant dyke and the Isortoq North giant dyke. The fine-grained Fe-Ti-V deposit hosted by the Isortoq South giant dyke, referred to as the Isortoq Fe-Ti-V deposit, is considered a good test site for the use of magnetic susceptibility for the mapping of ore grades. Here, we test this and show that the Fe, Ti and V distribution is controlled by titanomagnetite disseminated throughout fine-grained troctolite. The deposit displays a clear correlation between magnetic susceptibility and Fe, Ti and V grades in bulk samples of consecutive 2 m sections from 11 drill cores, totalling 2671 m in length. We observe that Fe, Ti and V are almost entirely hosted in titanomagnetite, which controls the magnetic susceptibility. Field measurements of the magnetic susceptibility can thus be considered as a reliable exploration tool for this type of mineralisation. We further consider the origins of the deposit by reconnaissance petrography, mineral and bulk rock chemistry of the large mass of aphanitic Fe-rich troctolite in the Isortoq South giant dyke. We suggest that the deposit may represent the base of a basanitic to trachybasaltic magma chamber, in which Fe-rich immiscible melts accumulated, crystallised and fractionated. The processes suggested here may apply to other giant dykes and intrusions of the Gardar Province. |
format |
Article in Journal/Newspaper |
author |
Diogo Rosa Alessandro Sandrin Troels F.D. Nielsen Høgni Vesturklett |
author_facet |
Diogo Rosa Alessandro Sandrin Troels F.D. Nielsen Høgni Vesturklett |
author_sort |
Diogo Rosa |
title |
Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland |
title_short |
Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland |
title_full |
Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland |
title_fullStr |
Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland |
title_full_unstemmed |
Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland |
title_sort |
petrography, geochemistry and magnetic susceptibility of the isortoq fe-ti-v deposit, isortoq giant dykes, south greenland |
publisher |
Geological Survey of Denmark and Greenland |
publishDate |
2020 |
url |
https://doi.org/10.34194/geusb.v44.4626 https://doaj.org/article/fea711fb34f7447eac3df7f57bb58e51 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Isortoq |
genre_facet |
Greenland Isortoq |
op_source |
GEUS Bulletin, Vol 44, Iss 0, Pp 1-8 (2020) |
op_relation |
https://geusbulletin.org/index.php/geusb/article/view/4626/11145 https://doaj.org/toc/2597-2154 2597-2154 doi:10.34194/geusb.v44.4626 https://doaj.org/article/fea711fb34f7447eac3df7f57bb58e51 |
op_doi |
https://doi.org/10.34194/geusb.v44.4626 |
container_title |
GEUS Bulletin |
_version_ |
1766017983992299520 |