| Titre | Formation of the Rock Canyon Creek carbonate-hosted REE-F-Ba deposit, British Columbia, Canada: Constraints from Mg-Sr isotopes of dolomite, calcite, and fluorite |
| |
| Auteur | Araoka, D; Simandl, G J; Paradis, S ; Yoshimura, T; Hoshino, M; Kon, Y |
| Source | Journal of Geochemical Exploration vol. 240, 107045, 2022 p. 1-15, https://doi.org/10.1016/j.gexplo.2022.107045  Accès ouvert |
| Image |  |
| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20220212 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.gexplo.2022.107045 |
| Media | papier; numérique; en ligne |
| Formats | pdf |
| Province | Colombie-Britannique |
| Lat/Long OENS | -141.4611 -112.8778 60.6483 47.8381 |
| Sujets | magnesium; isotopes; strontium; dolomites; calcite; fluorite; carbonate; géochimie; Sciences et technologie |
| Illustrations | cartes de localisation; photomicrographies; tableaux; graphiques; graphiques |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes volcaniques et sédimentaires - systèmes minéralisés de sulfure massif volcanogénique |
| Diffusé | 2022 06 21 |
| Résumé | (disponible en anglais seulement)
The Rock Canyon Creek REE-F-Ba deposit is a carbonate-hosted REE deposit located in the Alkaline Province of British Columbia, Canada, which hosts most REE
mineralization. It shares tectonic, stratigraphic and structural similarities with nearby Mississippi Valley-type deposits. To constrain the dolomitization and mineralization processes, the d26Mg, 87Sr/86Sr, and elemental compositions of dolomite,
calcite, and fluorite were determined. The d26Mg values of dolomite from the unmineralized zone (- 1.83 per mil and - 1.67 per mil) are consistent with marine evaporative dolomite, but those from the mineralized zone (- 0.97 per mil to - 0.17 per
mil) are higher and more variable. The linear 87Sr/86Sr-Sr/Mg relationships, both in the dolomite and calcite from the unmineralized zone, suggest dolomitization in an evaporative marine environment. The high d26Mg values with large variation and the
non-stoichiometric Ca/Mg ratios in the dolomite from the mineralized zone suggest that this dolomite interacted with a relatively low-temperature hydrothermal fluid (<200 °C). Considering the Na, Ca, Sr, Ba, and LREE-enrichment and low 87Sr/86Sr
signature in the dolomite from the mineralized zone as well as mineral paragenesis in the deposit, the most plausible scenario for the formation of the deposit is that marine-evaporitic dolomite re-equilibrated with basinal fluids along permeable
zones, and at a later stage, carbohydrothermal REE-bearing fluids infiltrated into the Rock Canyon Creek brecciated zone and deposited the REE mineralization. Late-stage, post-mineralization calcite veins and iron oxides formed in the upper part of
the deposit under supergene conditions, as suggested by combination of textural observations, REE patterns, and differences in isotopic compositions between dolomite and calcite from the mineralized zone. This study demonstrates that d26Mg,
87Sr/86Sr, and element/Mg ratios in carbonate minerals are useful for characterizing mineralizing fluids in carbonate-hosted deposits, and discriminating mineralization-related dolomite from marine evaporative dolomite and unmineralized hydrothermal
dolomite. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Le gisement d'éléments de terres rares-fluorite-barite (ETR-F-Ba) de Rock Canyon Creek est hébergé dans des carbonates situés dans la province
alcaline de la Colombie-Britannique, au Canada. Les compositions élémentaires de dolomite, de calcite et de fluorite et de divers isotopes (Mg et Sr) ont été déterminées pour déterminer les processus de dolomitisation et de minéralisation. La
dolomitisation s'est produite dans un environnement marin évaporatif et/ou a impliqué un fluide hydrothermal à température relativement basse (<200 °C). Les précipitations d'ETR se sont formées à la suite de l'interaction de fluides
carbohydrothermaux tardifs avec des fluides dolomitiques hydrothermaux précédemment formés le long de zones perméables. |
| GEOSCAN ID | 330520 |
|
|