| Titre | Geochronology, classification and mantle source characteristics of kimberlites and related rocks from the Rae Craton, Melville Peninsula, Nunavut, Canada |
| |
| Auteur | Sarkar, C; Kjarsgaard, B A ; Pearson, D G; Heaman, L M; Locock, A J;
Armstrong, J P |
| Source | Mineralogy and Petrology vol. 112, 2, 2018 p. 653-672, https://doi.org/10.1007/s00710-018-0632-5 |
| Image |  |
| Année | 2018 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200258 |
| Éditeur | Springer Wien |
| Réunion | 11th International Kimberlite Conference (IKC); Gaborone; BW; Septembre 18-22, 2017 |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1007/s00710-018-0632-5 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Nunavut |
| Région | Melville Peninsula |
| Sujets | kimberlites; olivine; manteau terrestre; Craton de Rae ; géochronologie; géochimie; pétrologie ignée et métamorphique; minéralogie; Cambrien |
| Illustrations | cartes de localisation; coupes; graphiques; diagrammes de différenciation; tableaux |
| Diffusé | 2018 08 28 |
| Résumé | (disponible en anglais seulement)
Detailed geochronology along with petrographic, mineralogical and geochemical studies have been conducted on recently found diamond-bearing kimberlitic and
related rocks in the Rae Craton at Aviat and Qilalugaq, Melville Peninsula, north-east Canada. Magmatic rocks from the Aviat pipes have geochemical (both bulk rock and isotopic) and mineralogical signatures (e.g., core to rim Al and Ba enrichment in
phlogopite) similar to Group I kimberlite. In contrast, Aviat intrusive sheets are similar to micaceous' Group II kimberlite (orangeite) in their geochemical and mineralogical characteristics (e.g., phlogopite and spinel compositions, highly enriched
Sr isotopic signature). Qilalugaq rocks with the least crustal contamination have geochemical and mineralogical signatures [e.g., high SiO2, Al2O3 and H2O; low TiO2 and CO2; less fractionated REE (rare earth elements), presence of primary
clinopyroxene, phlogopite and spinel compositions] that are similar to features displayed by olivine lamproites from Argyle, Ellendale and West Greenland. The Naujaat dykes, in the vicinity of Qilalugaq, are highly altered due to extensive
silicification and carbonation. However, their bulk rock geochemical signature and phlogopite chemistry are similar to Group I kimberlite. U-Pb perovskite geochronology reveals that Aviat pipes and all rocks from Qilalugaq have an early Cambrian
emplacement age (540-530Ma), with the Aviat sheets being similar to 30Ma younger. This volatile-rich potassic ultramafic magmatism probably formed by varying degrees of involvement of asthenospheric and lithospherically derived melts. The spectrum of
ages and compositions are similar to equivalent magmatic rocks observed from the nearby north-eastern North America and Western Greenland. The ultimate trigger for this magmatism could be linked to Neoproterozoic continental rifting during the
opening of the Iapetus Ocean and breakup of the Rodinia supercontinent. |
| GEOSCAN ID | 326670 |
|
|