| Titre | Magmatic architecture of the Esker intrusive complex in the Ring of Fire Intrusive Suite, McFaulds Lake greenstone belt, Superior Province, Ontario: Implications for the genesis of Cr and Ni-Cu-(PGE)
mineralization in an inflationary dyke-chonolith-sill complex |
| Télécharger | Téléchargement (publication entière) |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Houlé, M G; Lesher, C M; Metsaranta, R T; Sappin, A -A ; Carson, H J E; Schetselaar, E M; McNicoll, V; Laudadio, A |
| Source | Targeted Geoscience Initiative 5: Advances in the understanding of Canadian Ni-Cu-PGE and Cr ore systems - Examples from the Midcontinent Rift, the Circum-Superior Belt, the Archean Superior Province, and
Cordilleran Alaskan-type intrusions; par Bleeker, W (éd.);
Houlé, M G (éd.); Commission géologique du Canada, Dossier public 8722, 2020 p. 141-163, https://doi.org/10.4095/326892  Accès ouvert |
| Année | 2020 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/326892 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans Targeted
Geoscience Initiative 5: Advances in the understanding of Canadian Ni-Cu-PGE and Cr ore systems - Examples from the Midcontinent Rift, the Circum-Superior Belt, the Archean Superior Province, and Cordilleran Alaskan-type intrusions |
| Formats | pdf |
| Province | Ontario |
| SNRC | 43C/05; 43C/12; 43C/13; 43D/07; 43D/08; 43D/09; 43D/10; 43D/15; 43D/16; 43E/01; 43E/02; 43F/04 |
| Lat/Long OENS | -87.0000 -85.5319 53.2492 52.3411 |
| Sujets | gisements minéraux; nickel; cuivre; chrome; fer; titane; vanadium; phosphore; gîtes magmatiques; gîtes sulfureux; gisements stratiformes; genèse des minerais; minéralisation; contrôles des minerais;
établissement de modèles; géologie du substratum rocheux; lithologie; roches ignées; roches mafiques; roches ultramafiques; tholéiites; roches volcaniques; roches intrusives; komatiites; roches sédimentaires; formations ferrifères; cadre tectonique;
antécédents tectoniques; magmatisme; intrusions; filons rocheux; filons-couches; chonolites; fusion partielle; soufre; oxydes; Archéen; Province de Superior ; éléments du groupe de platine; géologie économique; Sciences et technologie; Nature et
environnement; Précambrien; Protérozoïque |
| Illustrations | cartes de localisation; graphiques; tableaux; cartes géomagnétiques; échelles stratigraphiques; photographies |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes de nickel-cuivre-EGP-chrome |
| Diffusé | 2020 09 08 |
| Résumé | (disponible en anglais seulement)
One of the dominant geological features in the arcuate, >175 km long, Mesoarchean to Neoarchean McFaulds Lake greenstone belt in northern Ontario is the
semi-continuous trend of mafic to ultramafic intrusions belonging to the Ring of Fire intrusive suite, which hosts world-class Cr mineralization, major Ni-Cu-(PGE) mineralization, and potentially significant Fe-Ti-V-(P) mineralization. It appears to
have been emplaced over a relatively short time interval of approximately 4 to 4.5 million years. The intrusive suite contains two subsuites: the less widely distributed Koper Lake subsuite, which consists of komatiitic ultramafic- dominated
intrusions and typically hosts Cr and Ni-Cu-(PGE) mineralization (e.g. Esker intrusive complex), and the more widely distributed Ekwan River subsuite, which consists of tholeiitic high-Fe-Ti mafic-dominated intrusions and typically hosts Fe-Ti-V-(P)
mineralization (e.g. Thunderbird intrusion). The Esker intrusive complex contains the majority of the known Cr and Ni-Cu-(PGE) mineralization in the Ring of Fire intrusive suite. It is a semi-continuous, structurally rotated, subvertical
ultramafic-mafic sill-like body that is composed of multiple intrusions with morphologies that vary from bladed dyke morphologies (e.g. Eagle's Nest), transitional dyke/chonolith morphologies (e.g. Double Eagle, AT-3, and AT- 8), to some with
transitional chonolith/sill morphologies (e.g. Black Thor). It extends over more than 16 km, youngs to the south-southeast, and is bordered to the north-northwest by several keel-like ultramafic intrusive bodies (e.g. AT-12, C-6, AT-5, AT-1). Clear
connections between AT-12 and AT-1 and the overlying Black Thor and Double Eagle intrusions, respectively, and the continuous spectrum of intrusion morphologies suggest that the keels were originally subhorizontal blade-shaped dykes (e.g. Eagle's
Nest), the upper parts of which expanded laterally to form transitional dykes/chonoliths (e.g. Double Eagle intrusion) and chonoliths/sills (e.g. Black Thor intrusion), which inflated laterally and coalesced over time to form the silllike Esker
intrusive complex. Most of the Ni-Cu-(PGE) mineralization in the Esker intrusive complex appears to have formed by incorporation of sulphur from footwall oxide-silicate-sulphide iron formations, a process that is similar to most other
komatiite-associated Ni-Cu-(PGE) deposits worldwide. A fundamental issue in the genesis of all stratiform chromite deposits is how to form thick layers of massive to semi-massive chromite, an issue exacerbated by the vast amounts of chromite in the
Esker intrusive complex. A genetic model that resolves the mass balance problem involves partial melting of Fe+/-Ti oxide-rich rocks (oxide-facies iron formation or ferrogabbro) and conversion of fine-grained oxide xenocrysts to chromite by reaction
with Cr-rich komatiitic magma in a dynamic magma conduit. This model has been recently challenged based on the capacity of komatiitic magma to dissolve large amounts of magnetite, which would prevent upgrading. However, alternative models cannot
explain the presence of composite chromite-silicate-sulphide grains with textures like those in footwall magnetite-silicate-sulphide facies iron formations. More research is required to reconcile the discrepancies. Regardless of their origin, the
wide diversity of mineral deposit types in the McFaulds Lake greenstone belt, including world-class Cr, significant Ni-Cu-(PGE), and potential Fe-Ti-V-(P) mineralization related to mafic and ultramafic rocks, make the Ring of Fire region an excellent
exploration target to increase the world's supply of critical minerals. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Les principaux objectifs de la phase 5 (2015-2020) du programme de l'Initiative géoscientifique ciblée (IGC) de Ressources naturelles Canada et
de la Commission géologique du Canada étaient de générer de nouvelles connaissances, méthodologies et modèles afin d'améliorer la capacité de l'industrie de l'exploration à détecter les gisements de minerai enfouis et les extensions des systèmes de
minerai existants, et de fournir des modèles pour cibler de nouvelles zones de gisement. Ce volume synthèse contient neuf articles individuels qui traitent des principales caractéristiques des gisements magmatiques, de l'échelle du dépôt à celui du
système magmatique, à partir de divers exemples canadiens reliés au projet Ni-Cu-PGE-Cr de l'IGC-5. |
| GEOSCAN ID | 326892 |
|
|