New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile
Iron oxide-apatite (IOA) or Kiruna-type deposits are an important source of iron and other elements including REE, U, Ag, and Co. The genesis of these deposits remains controversial, with models that range from a purely magmatic origin to others that involve variable degrees of hydrothermal fluid in...
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ftmurdochunivall:oai:alma.61MUN_INST:11135703110007891 2024-09-15T18:16:50+00:00 New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile Rojas, P.A. Barra, F. Deditius, A. Reich, M. Simon, A. Roberts, M. Rojo, M. 2018 pdf https://doi.org/10.1016/j.oregeorev.2018.01.003 https://researchportal.murdoch.edu.au/esploro/outputs/journalArticle/New-contributions-to-the-understanding-of/991005542246407891 https://researchportal.murdoch.edu.au/view/delivery/61MUN_INST/12135703100007891/13137051770007891 eng eng Elsevier BV ispartof: Ore Geology Reviews spage 413 epage 435 vol 93 doi:10.1016/j.oregeorev.2018.01.003 WOS:000427209200021 0169-1368 https://doi.org/10.1016/j.oregeorev.2018.01.003 991005542246407891 https://researchportal.murdoch.edu.au/esploro/outputs/journalArticle/New-contributions-to-the-understanding-of/991005542246407891 https://researchportal.murdoch.edu.au/view/delivery/61MUN_INST/12135703100007891/13137051770007891 alma:61MUN_INST/bibs/991005542246407891 © 2018 Elsevier B.V. Open text Article 2018 ftmurdochunivall https://doi.org/10.1016/j.oregeorev.2018.01.003 2024-08-15T00:52:51Z Iron oxide-apatite (IOA) or Kiruna-type deposits are an important source of iron and other elements including REE, U, Ag, and Co. The genesis of these deposits remains controversial, with models that range from a purely magmatic origin to others that involve variable degrees of hydrothermal fluid involvement. To elucidate the formation processes of this deposit type, we focused on the Chilean Iron Belt of Cretaceous age and performed geochemical analyses on samples from El Romeral, one of the largest IOA deposits in northern Chile. We present a comprehensive field emission electron microprobe analysis (FE-EMPA) dataset of magnetite, apatite, actinolite, pyroxene, biotite, pyrite, and chalcopyrite, obtained from representative drill core samples. Two different types of magnetite grains constitute the massive magnetite bodies: an early inclusion-rich magnetite (Type I); and a pristine, inclusion-poor magnetite (Type II) that usually appears as an overgrowth around Type I magnetite. High V (∼2500-2800 ppm) and Ti concentrations (∼80-3000 ppm), and the presence of high-temperature silicate mineral inclusions (e.g., pargasite, ∼800-1020°C) determined by micro-Raman analysis indicate a magmatic origin for Type I magnetite. On the other hand, high V (2300-2700 ppm) and lower Ti (50-400 ppm) concentrations of pristine, inclusion-poor Type-II magnetite indicate a shift from magmatic to hydrothermal conditions for this mineralization event. Furthermore, the composition of primary actinolite (Ca- and Mg-rich cores) within Type-II magnetite, the presence of F-rich apatite and high Co:Ni ratios (>1-10) of late stage pyrite mineralization are consistent with a high temperature (up to 840°C) genesis for the deposit. At shallow depths of the deposit, the presence of pyrite with low Co:Ni ratios (<0.5) and OH-rich apatite which contains higher Cl concentrations relative to F record a dominance of lower temperature hydrothermal conditions (<600°C) and a lesser magmatic contribution. This vertical zonation, which ... Article in Journal/Newspaper Kiruna Murdoch University Research Portal Ore Geology Reviews 93 413 435 |
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English |
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Iron oxide-apatite (IOA) or Kiruna-type deposits are an important source of iron and other elements including REE, U, Ag, and Co. The genesis of these deposits remains controversial, with models that range from a purely magmatic origin to others that involve variable degrees of hydrothermal fluid involvement. To elucidate the formation processes of this deposit type, we focused on the Chilean Iron Belt of Cretaceous age and performed geochemical analyses on samples from El Romeral, one of the largest IOA deposits in northern Chile. We present a comprehensive field emission electron microprobe analysis (FE-EMPA) dataset of magnetite, apatite, actinolite, pyroxene, biotite, pyrite, and chalcopyrite, obtained from representative drill core samples. Two different types of magnetite grains constitute the massive magnetite bodies: an early inclusion-rich magnetite (Type I); and a pristine, inclusion-poor magnetite (Type II) that usually appears as an overgrowth around Type I magnetite. High V (∼2500-2800 ppm) and Ti concentrations (∼80-3000 ppm), and the presence of high-temperature silicate mineral inclusions (e.g., pargasite, ∼800-1020°C) determined by micro-Raman analysis indicate a magmatic origin for Type I magnetite. On the other hand, high V (2300-2700 ppm) and lower Ti (50-400 ppm) concentrations of pristine, inclusion-poor Type-II magnetite indicate a shift from magmatic to hydrothermal conditions for this mineralization event. Furthermore, the composition of primary actinolite (Ca- and Mg-rich cores) within Type-II magnetite, the presence of F-rich apatite and high Co:Ni ratios (>1-10) of late stage pyrite mineralization are consistent with a high temperature (up to 840°C) genesis for the deposit. At shallow depths of the deposit, the presence of pyrite with low Co:Ni ratios (<0.5) and OH-rich apatite which contains higher Cl concentrations relative to F record a dominance of lower temperature hydrothermal conditions (<600°C) and a lesser magmatic contribution. This vertical zonation, which ... |
format |
Article in Journal/Newspaper |
author |
Rojas, P.A. Barra, F. Deditius, A. Reich, M. Simon, A. Roberts, M. Rojo, M. |
spellingShingle |
Rojas, P.A. Barra, F. Deditius, A. Reich, M. Simon, A. Roberts, M. Rojo, M. New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile |
author_facet |
Rojas, P.A. Barra, F. Deditius, A. Reich, M. Simon, A. Roberts, M. Rojo, M. |
author_sort |
Rojas, P.A. |
title |
New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile |
title_short |
New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile |
title_full |
New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile |
title_fullStr |
New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile |
title_full_unstemmed |
New contributions to the understanding of Kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the El Romeral deposit, Chile |
title_sort |
new contributions to the understanding of kiruna-type iron oxide-apatite deposits revealed by magnetite ore and gangue mineral geochemistry at the el romeral deposit, chile |
publisher |
Elsevier BV |
publishDate |
2018 |
url |
https://doi.org/10.1016/j.oregeorev.2018.01.003 https://researchportal.murdoch.edu.au/esploro/outputs/journalArticle/New-contributions-to-the-understanding-of/991005542246407891 https://researchportal.murdoch.edu.au/view/delivery/61MUN_INST/12135703100007891/13137051770007891 |
genre |
Kiruna |
genre_facet |
Kiruna |
op_relation |
ispartof: Ore Geology Reviews spage 413 epage 435 vol 93 doi:10.1016/j.oregeorev.2018.01.003 WOS:000427209200021 0169-1368 https://doi.org/10.1016/j.oregeorev.2018.01.003 991005542246407891 https://researchportal.murdoch.edu.au/esploro/outputs/journalArticle/New-contributions-to-the-understanding-of/991005542246407891 https://researchportal.murdoch.edu.au/view/delivery/61MUN_INST/12135703100007891/13137051770007891 alma:61MUN_INST/bibs/991005542246407891 |
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© 2018 Elsevier B.V. Open |
op_doi |
https://doi.org/10.1016/j.oregeorev.2018.01.003 |
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Ore Geology Reviews |
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93 |
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413 |
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435 |
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1810454828602621952 |