LiveZilla Live Chat Software

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

Petrogenesis and economic potential of the Obatogamau Formation, Chibougamau area, Abitibi greenstone belt

Boucher Adrien, Mathieu Lucie, Hamilton Michael A., Bedeaux Pierre et Daigneault Réal. (2020). Petrogenesis and economic potential of the Obatogamau Formation, Chibougamau area, Abitibi greenstone belt. Canadian Journal of Earth Sciences,

Le texte intégral n'est pas disponible pour ce document.

URL officielle: http://dx.doi.org/doi:10.1139/cjes-2020-0032

Résumé

Unravelling the petrogenesis and stratigraphy of Archean mafic lava flows is essential to our comprehension of the early geodynamic evolution and economic potential of greenstone belts. This study focuses on one of the oldest and thickest sequences of lava flows observed in the Neoarchean Abitibi Subprovince (greenstone belt), i.e., the Obatogamau Formation. The undated formation extends for more than 100 km in an E-W direction and consists mostly of aphyric and feldspar megacryst-bearing basaltic-andesite lava flows. These lava flows are tholeiitic, mostly Fe-rich and have nearly homogeneous chemistry. Petrogenetic modelling carried out using MELTS software points to limited magmatic differentiation as most samples of mafic lava flows did not reach Fe-Ti-oxide saturation. Zircon U-Pb dating establishes a crystallization age of 2726.2 ± 1.6 Ma for a felsic unit located at an intermediate stratigraphic position in the sequence of lava flows. Constraints from stratigraphically overlying volcanic units suggest that the Obatogamau Formation was likely emplaced rapidly, possibly within a few million years and as a consequence of frequent replenishment of shallow magma accumulations. High eruption rates are consistent with short episodes of volcanic quiescence deduced from field observations, indicating non-optimal conditions for volcanogenic massive sulfide systems. The pressure and temperature of peak metamorphism deduced from amphibole chemistry, however, points to favorable conditions for the release of metamorphic fluids. The study area may thus be prospective for orogenic gold mineralization, provided that fluids had access to a source of gold and that structural conduits allowed for the channeling of hydrothermal fluids.

Type de document:Article publié dans une revue avec comité d'évaluation
Version évaluée par les pairs:Oui
Date:1 Décembre 2020
Sujets:Sciences naturelles et génie > Génie
Sciences naturelles et génie > Sciences appliquées
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:Pétrogénèse, stratigraphie, lave mafique archéenne, Abitibi, ceinture de roches vertes, Obatogamau
Déposé le:24 févr. 2021 21:34
Dernière modification:24 févr. 2021 21:34
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