| Titre | A Palaeoproterozoic diamond-bearing lithospheric mantle root beneath the Archean Sask Craton, Canada |
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| Auteur | Czas, J; Pearson, D G; Stachel, T; Kjarsgaard, B A ; Read, G H |
| Source | Lithos vol. 356-357, 105301, 2019 p. 1-14, https://doi.org/10.1016/j.lithos.2019.105301 |
| Image |  |
| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190572 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.lithos.2019.105301 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Saskatchewan |
| SNRC | 73 |
| Lat/Long OENS | -110.0000 -104.0000 56.0000 52.0000 |
| Sujets | potentiel minier; gisements minéraux; diamant; géologie du socle; lithologie; roches ignées; roches intrusives; kimberlites; manteau terrestre; lithosphère; craton; analyses des éléments en trace;
analyses des éléments majeurs; etudes isotopiques; osmium; grenat; équilibres de phases; conditions de pression-température; analyses thermiques; Archéen; Champ de kimberlites de Fort à la Corne; Craton de Sask ; Bouclier Canadien;
Paléoprotérozoïque; Kimberlite de Star ; éléments du groupe de platine; géologie économique; géochimie; Sciences et technologie; Nature et environnement; Phanérozoïque; Mésozoïque; Crétacé; Précambrien; Protérozoïque |
| Programme | GEM : La géocartographie de l'énergie et des minéraux Diamants |
| Diffusé | 2019 11 21 |
| Résumé | (disponible en anglais seulement)
The recently recognised Sask Craton, a small terrane with Archean (3.3-2.5 Ga) crustal ages, is enclosed in the Paleoproterozoic (1.9-1.8 Ga) Trans Hudson
Orogen (THO). Only limited research has been conducted on this craton, yet it hosts major diamond deposits within the Cretaceous (~106 to ~95 Ma) Fort à la Corne (FALC) Kimberlite Field. This study describes major, trace and platinum group element
data, as well as osmium isotopic data from peridotitic mantle xenoliths (n = 26) from the Star and Orion South kimberlites. The garnet-bearing lithospheric mantle is dominated by moderately depleted lherzolite. Equilibration pressures and
temperatures (2.7 to 5.5 GPa and 840 to 1250 °C) for these garnet peridotites define a cool geotherm indicative of a 210 km thick lithosphere, similar to other cratons worldwide. Many of the peridotite xenoliths show the major and trace element
signatures of carbonatitic and kimberlitic melt metasomatism. The Re-Os isotopic data yield TRD (time of Re-depletion) model ages, which provide minimum estimates for the timing of melt depletion, ranging from 2.4 to 0.3 Ga, with a main mode spanning
from 2.4 to 1.7 Ga. No Archean ages were recorded. This finding and the complex nature of events affecting this terrane from the Archean through the Palaeoproterozoic provide evidence that the majority of the lithospheric mantle was depleted and
stabilised in the Palaeoproterozoic, significantly later than the Archean crust. The timing of the dominant lithosphere formation is linked to rifting (~2.2 Ga - 2.0 Ga), and subsequent collision (1.9-1.8 Ga) of the Superior and Hearne craton during
the Wilson cycle of the Trans Hudson Orogen. |
| GEOSCAN ID | 321892 |
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