LiveZilla Live Chat Software

Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Critical controls on the formation of contact-style PGE-Ni-Cu mineralization: Evidence from the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia

Karykowski Bartosz T., Maier Wolfgang D., Groshev Nikolay Y., Barnes Sarah-Jane, Pripachkin Pavel V., McDonald Iain et Savard Dany. (2018). Critical controls on the formation of contact-style PGE-Ni-Cu mineralization: Evidence from the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia. Economic Geology, 113, (4), p. 911-935.

[img] PDF - Version publiée
Administrateurs seulement

1MB

URL officielle: https://doi.org/10.5382/econgeo.2018.4576

Résumé

The Paleoproterozoic Monchegorsk Complex, located in the Russian part of the Fennoscandian Shield, constitutes one of the largest mafic-ultramafic layered intrusions in Europe. The complex hosts extensive contact-style platinum group element-Ni-Cu sulfide mineralization along its margin, irrespective of the host lithology, which ranges from peridotite to pyroxenite and gabbronorite. The mineralized intervals reach up to 3 ppm Pt + Pd and attain a thickness of up to 50 m in the central portions of the intrusion, thinning toward the periphery. Our study shows that the key process controlling the size and grade of a contact-style deposit in the Mon-chegorsk Complex was the efficiency of sulfide collection in distinct zones of the intrusion. Strongly mineralized basal contacts are always associated with intense brecciation and the presence of large amounts of felsic pegmatite, suggesting a multistage emplacement of the mafic-ultramafic succession. Thermal modeling demonstrates that multiple episodes of magma influx are required to allow for significant partial melting of the basement. Moreover, the interaction between magma and basement led to the local addition of water and, potentially, carbon dioxide to the magma, resulting in local small-scale dissolution of cumulus phases and a reduction in viscosity of the interstitial melt. This increased the porosity of the mush in the vicinity of the lower intrusion contact, which promoted preferential sulfide liquid accumulation at the base, while the local decrease in magma viscosity facilitated gravitational settling of sulfide droplets. These factors led to an efficient collection of sulfide liquid, especially in the center of the complex, where permeability was maintained the longest due to slower cooling relative to more peripheral parts.

Type de document:Article publié dans une revue avec comité d'évaluation
Volume:113
Numéro:4
Pages:p. 911-935
Version évaluée par les pairs:Oui
Date:2018
Sujets:Sciences naturelles et génie > Sciences naturelles > Sciences de la terre (géologie, géographie)
Département, module, service et unité de recherche:Départements et modules > Département des sciences appliquées > Unité d'enseignement en sciences de la Terre
Mots-clés:igneous rocks, magmas, metal ores, metals, mineral exploration, nickel ores, Europe, gabbros, intrusions, Kola Russian Federation, Murmansk Russian Federation, copper ores, pegmatite, Precambrian, Proterozoic, pyroxenite, norite, Commonwealth of Independent States, Paleoproterozoic, platinum ores, Fennoscandian Shield, granites, mineral deposits, genesis plutonic rocks, ultramafics, peridotites, platinum group, Russian Federation, upper Precambrian
Déposé le:02 avr. 2019 01:26
Dernière modification:02 avr. 2019 01:26
Afficher les statistiques de telechargements

Éditer le document (administrateurs uniquement)

Creative Commons LicenseSauf indication contraire, les documents archivés dans Constellation sont rendus disponibles selon les termes de la licence Creative Commons "Paternité, pas d'utilisation commerciale, pas de modification" 2.5 Canada.

Bibliothèque Paul-Émile-Boulet, UQAC
555, boulevard de l'Université
Chicoutimi (Québec)  CANADA G7H 2B1
418 545-5011, poste 5630