| Titre | Yukon's Carlin-Type gold deposits (Rackla Belt, Canada): main characteristics and new insights on alteration styles and geochemistry |
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| Auteur | Pinet, N; Sack, P; Mercier-Langevin, P; Davis, W J ; Petts, D C; Lavoie, D; Percival, J B; Dubé, B; Colpron, M; Ardakani, O H; Brake, V I |
| Source | ; Economic Geology vol. 117, no. 4, 2022 p. 875-904, https://doi.org/10.5382/econgeo.4899 |
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| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20210254 |
| Éditeur | Society of Economic Geologists |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.5382/econgeo.4899 |
| Media | papier; numérique; en ligne |
| Formats | pdf |
| Province | Yukon |
| SNRC | 105K/01; 105K/02; 105K/03; 105K/04 |
| Lat/Long OENS | -134.0000 -132.0000 64.2500 64.0000 |
| Sujets | or; gisements minéraux; temperature; pyrite; minéralogie |
| Illustrations | cartes de localisation; modèles schématiques; profils stratigraphiques; plans; photographies; graphiques géochimiques; tableaux; coupes; graphiques |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes minéralisés aurifères |
| Diffusé | 2022 02 01 |
| Résumé | (disponible en anglais seulement)
In central Yukon, the Neoproterozoic to Carboniferous complexly deformed Rackla belt is along the northern boundary of the Selwyn basin. Toward the eastern end
of the Rackla belt, a series of gold deposits in the Nadaleen trend exhibit similarities with Carlin-type deposits of the southwestern United States and may represent some of the best examples of this type of mineralization outside Nevada. These
replacement-style gold deposits are hosted in two Neoproterozoic carbonate-dominated intervals and in a Paleozoic siltstone/mudstone unit at the contact with less permeable strata. In Neoproterozoic-hosted deposits, mineralized zones are grossly
concordant with bedding. Favorable host rocks (including sedimentary units formed through debris flows) form complexly shaped faulted anticlines that constituted mixed stratigraphic/structural traps for mineralizing fluids. This and the association
of gold with arsenic-rich pyrite, the common occurrence of realgar/orpiment, alteration styles dominated by decarbonatization of impure carbonate rocks, late Au-stage calcite characterized by a depleted d18O signature, the very low base metal content
and Ag/Au ratio, and enrichment in a series of diagnostic pathfinder elements (Hg, Tl ± Sb, As) are among the key features that are consistent with classification of the eastern Rackla belt as a Carlin-type district. Mineralization style varies
significantly at the centimeter to 10-m scale, indicating that mineralizing fluids exploited permeable pathways, regardless of their sedimentary and/or tectonic origin. Alternating finely laminated limestone, siltstone, and floatstone intervals are
the dominant host rocks to mineralization in the Conrad, Sunrise, and Osiris deposits. Premineralization fractures acted as feeders for selective bed replacement, and premineralization calcite vein networks, preferentially dissolved by early acidic
fluids, acted as conduits to later gold-bearing fluids. Limited evidence suggests that synmineralization deformation was relatively minor and possibly dominated by oblique strike-slip faulting. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Dans la partie centrale du Yukon, plusieurs zones aurifères montrent des similitudes claires avec les gisements de type Carlin et peuvent être
considérées comme parmi les meilleurs exemples de ce type de minéralisation en dehors du Nevada. Cette contribution synthétise les caractéristiques principales des zones aurifères et apporte de nouvelles données et concepts sur les paramètres
contrôlant la minéralisation. La contribution a des conséquences significatives sur la métallogénie régionale et les processus de formation des zones minéralisées. |
| GEOSCAN ID | 328884 |
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