The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization

Alkaline igneous rocks host many High Field Strength (HFSE) and Rare Earth Element (REE) deposits, which are key for the global low-carbon energy transition. To better target these, a better understanding of alteration associated with silicate-related ore deposits is required. Fluid-rock interaction...

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Main Author: Sokół, Krzysztof
Other Authors: Finch, Adrian Anthony, Hutchison, William, Cloutier, Jonathan, Humphreys, Madeleine C.S., Natural Environment Research Council (NERC), NERC Isotope Geosciences Laboratories (NIGL)
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: The University of St Andrews 2023
Subjects:
Online Access:http://hdl.handle.net/10023/27744
https://doi.org/10.17630/sta/493
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spelling ftstandrewserep:oai:research-repository.st-andrews.ac.uk:10023/27744 2023-07-02T03:32:26+02:00 The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization Sokół, Krzysztof Finch, Adrian Anthony Hutchison, William Cloutier, Jonathan Humphreys, Madeleine C.S. Natural Environment Research Council (NERC) NERC Isotope Geosciences Laboratories (NIGL) 395 2023-06-05T10:15:36Z application/pdf http://hdl.handle.net/10023/27744 https://doi.org/10.17630/sta/493 en eng The University of St Andrews University of Tasmania; Durham University http://hdl.handle.net/10023/27744 https://doi.org/10.17630/sta/493 NE/L002590/1 IP-1906-0619 Creative Commons Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ 2025-04-22 Thesis restricted in accordance with University regulations. Restricted until 22nd April 2025 Energy transition Alkaline magmas Fenitization High-field-strength elements Rare metals Ore deposits Mineral chemistry Greenland Late-stage fluids Stable isotopes Major and trace element chemistry Geochronology Fluid inclusions QE462.A4S7 Alkalic igneous rocks Nonferrous metals Mineralogical chemistry Thesis Doctoral PhD Doctor of Philosophy 2023 ftstandrewserep https://doi.org/10.17630/sta/493 2023-06-13T18:31:19Z Alkaline igneous rocks host many High Field Strength (HFSE) and Rare Earth Element (REE) deposits, which are key for the global low-carbon energy transition. To better target these, a better understanding of alteration associated with silicate-related ore deposits is required. Fluid-rock interaction around syenite forms altered haloes (’fenite’), normally uneconomic, but hosting many of the normally immobile HFSE expelled from the magmatic hearth. The fluid parameters which control the transport and deposition of these elements in the crust, their composition and the element speciation within need to be better constrained. Here a field study of an exceptionally exposed fenite (Gardar Province, SW Greenland) was followed by major and trace element, and stable isotope (O-H-S) analyses of whole rocks and minerals, and the investigation of fluid inclusion assemblages. The field data show the volcano-sedimentary wall-rocks to the west of Illerfissalik centre were altered by the ejection of metasomatic fluids. Fenitized sediment comprises a skarn-like (garnet-absent) calc-silicate assemblage developed interstitially, often along relict structures, later subjected to short-lived Na– Fe(III) –Ti alteration. Using oxygen isotope equilibria, the temperature of the causal fluid was estimated at ~750°C suggesting a magmatic origin. The differences in O, H and S isotopic data also indicate the system underwent fluid-driven exchange with the country rocks, potentially mixing with externally derived meteoric water. Elements including Ti, Zr, Nb and REE are mobile during alteration, but they precipitate as silicates and phosphates mainly in the late-stage in the basement granite, while rare chevkinite and titanite host much of the early-stage HFSE in the Eriksfjord. An estimated total REE-oxide cargo mobilized from Illerfissalik (~43 Mt) rivals the tonnages of many major ore deposits (i.e. Kringlerne, Ilímaussaq) and underscores how critical fenitization is as a tipping point during evolution of fertile magmas in the upper ... Doctoral or Postdoctoral Thesis Greenland University of St Andrews: Digital Research Repository Greenland Illerfissalik ENVELOPE(-45.267,-45.267,61.050,61.050) Wall Rocks ENVELOPE(-129.312,-129.312,52.728,52.728)
institution Open Polar
collection University of St Andrews: Digital Research Repository
op_collection_id ftstandrewserep
language English
topic Energy transition
Alkaline magmas
Fenitization
High-field-strength elements
Rare metals
Ore deposits
Mineral chemistry
Greenland
Late-stage fluids
Stable isotopes
Major and trace element chemistry
Geochronology
Fluid inclusions
QE462.A4S7
Alkalic igneous rocks
Nonferrous metals
Mineralogical chemistry
spellingShingle Energy transition
Alkaline magmas
Fenitization
High-field-strength elements
Rare metals
Ore deposits
Mineral chemistry
Greenland
Late-stage fluids
Stable isotopes
Major and trace element chemistry
Geochronology
Fluid inclusions
QE462.A4S7
Alkalic igneous rocks
Nonferrous metals
Mineralogical chemistry
Sokół, Krzysztof
The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
topic_facet Energy transition
Alkaline magmas
Fenitization
High-field-strength elements
Rare metals
Ore deposits
Mineral chemistry
Greenland
Late-stage fluids
Stable isotopes
Major and trace element chemistry
Geochronology
Fluid inclusions
QE462.A4S7
Alkalic igneous rocks
Nonferrous metals
Mineralogical chemistry
description Alkaline igneous rocks host many High Field Strength (HFSE) and Rare Earth Element (REE) deposits, which are key for the global low-carbon energy transition. To better target these, a better understanding of alteration associated with silicate-related ore deposits is required. Fluid-rock interaction around syenite forms altered haloes (’fenite’), normally uneconomic, but hosting many of the normally immobile HFSE expelled from the magmatic hearth. The fluid parameters which control the transport and deposition of these elements in the crust, their composition and the element speciation within need to be better constrained. Here a field study of an exceptionally exposed fenite (Gardar Province, SW Greenland) was followed by major and trace element, and stable isotope (O-H-S) analyses of whole rocks and minerals, and the investigation of fluid inclusion assemblages. The field data show the volcano-sedimentary wall-rocks to the west of Illerfissalik centre were altered by the ejection of metasomatic fluids. Fenitized sediment comprises a skarn-like (garnet-absent) calc-silicate assemblage developed interstitially, often along relict structures, later subjected to short-lived Na– Fe(III) –Ti alteration. Using oxygen isotope equilibria, the temperature of the causal fluid was estimated at ~750°C suggesting a magmatic origin. The differences in O, H and S isotopic data also indicate the system underwent fluid-driven exchange with the country rocks, potentially mixing with externally derived meteoric water. Elements including Ti, Zr, Nb and REE are mobile during alteration, but they precipitate as silicates and phosphates mainly in the late-stage in the basement granite, while rare chevkinite and titanite host much of the early-stage HFSE in the Eriksfjord. An estimated total REE-oxide cargo mobilized from Illerfissalik (~43 Mt) rivals the tonnages of many major ore deposits (i.e. Kringlerne, Ilímaussaq) and underscores how critical fenitization is as a tipping point during evolution of fertile magmas in the upper ...
author2 Finch, Adrian Anthony
Hutchison, William
Cloutier, Jonathan
Humphreys, Madeleine C.S.
Natural Environment Research Council (NERC)
NERC Isotope Geosciences Laboratories (NIGL)
format Doctoral or Postdoctoral Thesis
author Sokół, Krzysztof
author_facet Sokół, Krzysztof
author_sort Sokół, Krzysztof
title The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
title_short The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
title_full The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
title_fullStr The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
title_full_unstemmed The nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
title_sort nature of fluids associated with the subvolcanic alkaline magmas and their role in 'hi-tech' metal transport and mineralization
publisher The University of St Andrews
publishDate 2023
url http://hdl.handle.net/10023/27744
https://doi.org/10.17630/sta/493
op_coverage 395
long_lat ENVELOPE(-45.267,-45.267,61.050,61.050)
ENVELOPE(-129.312,-129.312,52.728,52.728)
geographic Greenland
Illerfissalik
Wall Rocks
geographic_facet Greenland
Illerfissalik
Wall Rocks
genre Greenland
genre_facet Greenland
op_relation http://hdl.handle.net/10023/27744
https://doi.org/10.17630/sta/493
NE/L002590/1
IP-1906-0619
op_rights Creative Commons Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/
2025-04-22
Thesis restricted in accordance with University regulations. Restricted until 22nd April 2025
op_doi https://doi.org/10.17630/sta/493
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