| Titre | Are there elephants hiding in the Jurassic of Yukon? A tectonomagmatic perspective on porphyry prospectivity |
| Télécharger | Téléchargements |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Chapman, J B |
| Source | TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation; par Rogers, N (éd.); Commission géologique du Canada, Dossier public 7843, 2015 p. 493-506, https://doi.org/10.4095/296485  Accès ouvert |
| Liens | Canadian Database of Geochemical Surveys, downloadable files
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| Liens | Banque de données de levés géochimiques du Canada,
fichiers téléchargeables
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| Image |  |
| Année | 2015 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/296485 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans TGI 4 -
Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation |
| Formats | pdf |
| Province | Yukon |
| SNRC | 105D; 105E; 105L; 115A; 115H; 115I |
| Région | Whitehorse; Carmacks |
| Lat/Long OENS | -138.0000 -134.5000 63.0000 60.5000 |
| Sujets | gisements porphyriques; cuivre porphyrique; prospection minière; minéralisation; tungstène; molybdène; cuivre; or; milieux tectoniques; cadre tectonique; gîtes magmatiques; roches magmatiques; Granite de
Nashwaak ; géologie économique; tectonique; Mésozoïque; Jurassique |
| Illustrations | cartes de localisation; photographies; graphiques; diagrammes ternaires |
| Programme | Initiative géoscientifique ciblée (IGC-4) Étude des gîtes porphyriques |
| Diffusé | 2015 06 11; 2023 03 17 |
| Résumé | (disponible en anglais seulement)
Within British Columbia, Triassic-Jurassic felsic plutonic and intrusive rocks of the Stikinia and Quesnellia terranes are very much considered “elephant
country”, and are spatially and genetically associated with some of the most significant porphyry Cu-Mo deposits in North America. However, where these terranes meet and merge in central Yukon, little significant mineralization has been discovered in
similarly aged felsic plutonic rocks and they host only one operating Cu mine, despite outcrop covering hundreds of square kilometres. The reasons for this discrepancy are not clear. In order to provide assessment of the tectonomagmatic setting and
porphyry prospectivity of Jurassic plutonic rocks within Yukon, 65 unmineralized samples from across the district have been analyzed for their whole rock major and trace element geochemistry, and their zircon Ce4+/Ce3+ ratios were determined by laser
ablation ICP-MS. Most samples plot within calc-alkaline to high K calc-alkaline fields within a plot of SiO2 vs. K2O, although data display significant scatter and lack any strong trend, suggestive of later disturbance of the K content. Rocks from
all sampling locations show HFSE depletions and negative Nb anomalies characteristic of suprasubduction zone environments, and commonly depleted HREE patterns are suggestive of melt generated below the depth of garnet stability. Plots of Sr/Y vs. Y
and La/YbN vs. YbN both indicate significant adakite-like and adakitic characteristics in a subset of the samples analysed. Taken together, the suprasubduction zone character and presence of adakite-like magmatism have been suggested as strong
indicators of high porphyry potential in other parts of the world. Zircon Ce4+/Ce3+ values were highly variable and ranged up to more than 2100, an order of magnitude greater than previous studies have suggested as a porphyry prospectivity threshold.
However, aluminum-inhornblende data and Cu and Mo contents well below crustal abundances suggest that Jurassic plutonic rocks may represent the mid-crustal, volatile-depleted residue of porphyry-related magmatism that has been eroded away. Future
exploration for Cu-Mo-Au mineralization within Yukon will depend on understanding of tectonic uplift across the region, and better constraint on the genesis of known mineralization. |
| Sommaire | (Résumé en langage clair et simple, non publié)
L'Initiative géoscientifique ciblée (IGC-4) est un programme géoscientifique fédéral de collaboration qui fournit à l'industrie les
connaissances géoscientifiques et les techniques novatrices de prochaine génération dont elle a besoin pour mieux détecter les gîtes minéraux enfouis, réduisant ainsi certains risques liés à l'exploration. Ce volume résume les activités de recherche
effectuées dans le cadre du projet de minéralisation lié à des intrusions de l'Initiative géoscientifique ciblée 4 qui était axé sur des systèmes minéralisés porphyriques associés aux dépôts de Cu et de Cu-Mo dans le centre-sud de la
Colombie-Britannique et aux dépôts de Sn-W-Mo-In au Nouveau-Brunswick, en Nouvelle-Écosse et à Terre-Neuve-et-Labrador. |
| GEOSCAN ID | 296485 |
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