Hydrothermal alteration of the Kemi layered intrusion
Abstract. The Kemi chromite deposit is located near the towns of Kemi and Tornio (northern Finland). The mineralization is hosted within the mafic-ultramafic Kemi intrusion (~2.4 Ga) that is part of the Tornio–Näränkävaara belt. The main chromite zone is located in the basal part of the intrusion an...
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ftunivoulu:oai:oulu.fi:nbnfioulu-201904241520 2023-07-30T04:05:49+02:00 Hydrothermal alteration of the Kemi layered intrusion Botello Becerra, F. (Fabian) 2019-04-23 application/pdf http://jultika.oulu.fi/Record/nbnfioulu-201904241520 eng eng University of Oulu info:eu-repo/semantics/openAccess © Fabian Botello Becerra, 2019 info:eu-repo/semantics/masterThesis info:eu-repo/semantics/publishedVersion 2019 ftunivoulu 2023-07-08T19:57:44Z Abstract. The Kemi chromite deposit is located near the towns of Kemi and Tornio (northern Finland). The mineralization is hosted within the mafic-ultramafic Kemi intrusion (~2.4 Ga) that is part of the Tornio–Näränkävaara belt. The main chromite zone is located in the basal part of the intrusion and is enveloped and intercalated by peridotites and bronzites. Hydrothermal alteration has pervasively affected the intrusion mainly in the lower and upper segments, leaving the middle part relatively unaltered. These lithologies can still be identified due to the preservation of their primary textures. The altered ultramafic lithologies had been previously catalogued as cumulate, chlorite, amphibole, serpentine and pyroxene peridotites, amphibole and talc pyroxenites, and serpentinites. Further petrographic observations suggest that the ultramafic rocks experienced at least six episodes of hydrothermal alteration that lead to the replacement of primary minerals to assemblages of serpentine, chlorite, amphibole, carbonate and talc. Evidences in the petrography and mineral chemistry suggests the alteration fluid evolve towards more silica rich compositions. The hydrothermal fluids responsible for Kemi intrusion alterations can be related to the metamorphism of the footwall rocks during the Svecofennian Orogeny. Variations in alteration patterns and mineralogy as well as variations in the mineral chemistry do not correlate with the proximity to the chromitite ore zone. Master Thesis Northern Finland Jultika - University of Oulu repository Tornio ENVELOPE(24.147,24.147,65.848,65.848) |
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Open Polar |
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Jultika - University of Oulu repository |
op_collection_id |
ftunivoulu |
language |
English |
description |
Abstract. The Kemi chromite deposit is located near the towns of Kemi and Tornio (northern Finland). The mineralization is hosted within the mafic-ultramafic Kemi intrusion (~2.4 Ga) that is part of the Tornio–Näränkävaara belt. The main chromite zone is located in the basal part of the intrusion and is enveloped and intercalated by peridotites and bronzites. Hydrothermal alteration has pervasively affected the intrusion mainly in the lower and upper segments, leaving the middle part relatively unaltered. These lithologies can still be identified due to the preservation of their primary textures. The altered ultramafic lithologies had been previously catalogued as cumulate, chlorite, amphibole, serpentine and pyroxene peridotites, amphibole and talc pyroxenites, and serpentinites. Further petrographic observations suggest that the ultramafic rocks experienced at least six episodes of hydrothermal alteration that lead to the replacement of primary minerals to assemblages of serpentine, chlorite, amphibole, carbonate and talc. Evidences in the petrography and mineral chemistry suggests the alteration fluid evolve towards more silica rich compositions. The hydrothermal fluids responsible for Kemi intrusion alterations can be related to the metamorphism of the footwall rocks during the Svecofennian Orogeny. Variations in alteration patterns and mineralogy as well as variations in the mineral chemistry do not correlate with the proximity to the chromitite ore zone. |
format |
Master Thesis |
author |
Botello Becerra, F. (Fabian) |
spellingShingle |
Botello Becerra, F. (Fabian) Hydrothermal alteration of the Kemi layered intrusion |
author_facet |
Botello Becerra, F. (Fabian) |
author_sort |
Botello Becerra, F. (Fabian) |
title |
Hydrothermal alteration of the Kemi layered intrusion |
title_short |
Hydrothermal alteration of the Kemi layered intrusion |
title_full |
Hydrothermal alteration of the Kemi layered intrusion |
title_fullStr |
Hydrothermal alteration of the Kemi layered intrusion |
title_full_unstemmed |
Hydrothermal alteration of the Kemi layered intrusion |
title_sort |
hydrothermal alteration of the kemi layered intrusion |
publisher |
University of Oulu |
publishDate |
2019 |
url |
http://jultika.oulu.fi/Record/nbnfioulu-201904241520 |
long_lat |
ENVELOPE(24.147,24.147,65.848,65.848) |
geographic |
Tornio |
geographic_facet |
Tornio |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_rights |
info:eu-repo/semantics/openAccess © Fabian Botello Becerra, 2019 |
_version_ |
1772818029347864576 |