| Titre | Generation of high-pH groundwaters and H2 gas by groundwater-kimberlite interaction, northeastern Ontario, Canada |
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| Auteur | Sader, J A; Harrison, A L; McClenaghan, M B ; Hamilton, S M; Clark, I D; Sherwood Lollar, B; Leybourne, M I |
| Source | Canadian Mineralogist vol. 59, issue 5, 2021 p. 1261-1276, https://doi.org/10.3749/canmin.2000048 |
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| Année | 2021 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20210302 |
| Éditeur | Association minéralogique du Canada |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.3749/canmin.2000048 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Ontario |
| SNRC | 32D/03; 32D/04; 32D/05; 32D/06; 32D/11; 32D/12 |
| Région | Kirkland Lake |
| Lat/Long OENS | -80.0000 -79.3333 48.5833 48.0000 |
| Sujets | eau souterraine; géochimie des eaux souterraines; hydrogene; alcalinité; hydroxydes; géologie du substratum rocheux; lithologie; roches ignées; roches intrusives; kimberlites; etudes isotopiques; isotopes
d'hydrogène; isotopes de carbone; rapports strontium-strontium; méthane; géochimie du magnesium; géochimie du potassium; géothermométrie; serpentinisation; établissement de modèles; exploitation minière; résidus; hydrogéologie; géochimie; Sciences et
technologie; Nature et environnement; Économie et industrie; Phanérozoïque; Mésozoïque; Jurassique |
| Illustrations | cartes de localisation; cartes géolscientiques généralisées; tableaux; graphiques |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes minéralisés - intrusions/porphyriques |
| Diffusé | 2021 10 07 |
| Résumé | (disponible en anglais seulement)
We report new isotopic data for H2 and CH4 gases and Sr for groundwater collected from Jurassic Kirkland Lake kimberlites in northern Ontario, Canada.
Groundwaters interacting with kimberlites have elevated pH (up to 12.4), are reducing (Eh as low as the H2-H2O couple), are dominated by OH- alkalinity, and have non-radiogenic (mantle) 87Sr/86Sr values (~0.706-0.707). Most significantly, the highest
pH groundwaters have low Mg, high K/Mg, and are associated with abundant reduced gases (H2 ± CH4). Open system conditions favor higher dissolved inorganic carbon and CH4 production, whereas under closed system conditions low DIC, elevated OH-
alkalinity, and H2 production are enhanced. Hydrogen gas is isotopically depleted (delta-2HH2 = -771 to -801 permille), which, combined with delta-2HH2O, yields geothermometry temperatures of serpentinization of 5-25 °C. Deviation of H2-rich
groundwaters (by up to 10 permille) from the meteoric water line is consistent with Rayleigh fractionation during reduction of water to H2. Methane is characterized by delta-13CCH4 = -35.8 to -68 permille and delta-2HCH4 = -434 permille. The origin
of CH4 is inconclusive and there is evidence to support both biogenic and abiogenic origins. The modeled groundwater-kimberlite reactions and production of elevated concentrations of H2 gas suggest uses for diamond-production tailings, as a source of
H2 for fuel cells and as a carbon sink. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cet article résume les résultats d'une étude détaillée des signatures des eaux souterraines des kimberlites dans le nord-est de l'Ontario. Cette
étude a été réalisée dans le cadre de l'Initiative géoscientifique ciblée de la Commission géologique du Canada. |
| GEOSCAN ID | 328965 |
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