Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering

A variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelandia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others fo...

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Detalles Bibliográficos
Autores: Garuti, Giorgio, Zaccarini, Federica, Proenza, Joaquin A., Thalhammer, Oskar A. R., Angeli, Nelson [UNESP]
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2012
País:Brasil
Institución:Universidade Estadual Paulista (UNESP)
Repositorio:Repositório Institucional da UNESP
Idioma:inglés
OAI Identifier:oai:repositorio.unesp.br:11449/117517
Acceso en línea:http://dx.doi.org/10.3390/min2040365
http://hdl.handle.net/11449/117517
Access Level:acceso abierto
Palabra clave:Chromitite
PGM
laterite
weathering
Niquelandia
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spelling Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic WeatheringChromititePGMlateriteweatheringNiquelandiaA variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelandia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary). Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.Montan Univ Leoben, Dept Appl Geosci & Geophys, A-8700 Leoben, AustriaUniv Barcelona, Fac Geol, Dept Crystallog Mineral & Ore Deposits, E-08028 Barcelona, SpainUniv Estadual Paulista, Dept Petrol & Metallogeny, BR-13500 Rio Claro, SP, BrazilUniv Estadual Paulista, Dept Petrol & Metallogeny, BR-13500 Rio Claro, SP, BrazilCGL2009-10924CGL2012-36263Mdpi AgMontan Univ LeobenUniv BarcelonaUniversidade Estadual Paulista (Unesp)2015-03-18T15:56:21Z2015-03-18T15:56:21Z2012-12-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article365-384application/pdfhttp://dx.doi.org/10.3390/min2040365Minerals. Basel: Mdpi Ag, v. 2, n. 4, p. 365-384, 2012.2075-163Xhttp://hdl.handle.net/11449/11751710.3390/min2040365WOS:000209087700007WOS000209087700007.pdf0864918679971906Web of Sciencereponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengMinerals1.835info:eu-repo/semantics/openAccessGaruti, GiorgioZaccarini, FedericaProenza, Joaquin A.Thalhammer, Oskar A. R.Angeli, Nelson [UNESP]2024-11-28T13:41:41Zoai:repositorio.unesp.br:11449/117517Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestrepositoriounesp@unesp.bropendoar:29462024-11-28T13:41:41Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
title Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
spellingShingle Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
Garuti, Giorgio
Chromitite
PGM
laterite
weathering
Niquelandia
title_short Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
title_full Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
title_fullStr Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
title_full_unstemmed Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
title_sort Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering
dc.creator.none.fl_str_mv Garuti, Giorgio
Zaccarini, Federica
Proenza, Joaquin A.
Thalhammer, Oskar A. R.
Angeli, Nelson [UNESP]
author Garuti, Giorgio
author_facet Garuti, Giorgio
Zaccarini, Federica
Proenza, Joaquin A.
Thalhammer, Oskar A. R.
Angeli, Nelson [UNESP]
author_role author
author2 Zaccarini, Federica
Proenza, Joaquin A.
Thalhammer, Oskar A. R.
Angeli, Nelson [UNESP]
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Montan Univ Leoben
Univ Barcelona
Universidade Estadual Paulista (Unesp)
dc.subject.por.fl_str_mv Chromitite
PGM
laterite
weathering
Niquelandia
topic Chromitite
PGM
laterite
weathering
Niquelandia
description A variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelandia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary). Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.
publishDate 2012
dc.date.none.fl_str_mv 2012-12-01
2015-03-18T15:56:21Z
2015-03-18T15:56:21Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://dx.doi.org/10.3390/min2040365
Minerals. Basel: Mdpi Ag, v. 2, n. 4, p. 365-384, 2012.
2075-163X
http://hdl.handle.net/11449/117517
10.3390/min2040365
WOS:000209087700007
WOS000209087700007.pdf
0864918679971906
url http://dx.doi.org/10.3390/min2040365
http://hdl.handle.net/11449/117517
identifier_str_mv Minerals. Basel: Mdpi Ag, v. 2, n. 4, p. 365-384, 2012.
2075-163X
10.3390/min2040365
WOS:000209087700007
WOS000209087700007.pdf
0864918679971906
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv Minerals
1.835
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 365-384
application/pdf
dc.publisher.none.fl_str_mv Mdpi Ag
publisher.none.fl_str_mv Mdpi Ag
dc.source.none.fl_str_mv Web of Science
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv repositoriounesp@unesp.br
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score 15,198674

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