GEOSCAN Search Results: Fastlink


TitleGeochronology, classification and mantle source characteristics of kimberlites and related rocks from the Rae Craton, Melville Peninsula, Nunavut, Canada
AuthorSarkar, C; Kjarsgaard, B AORCID logo; Pearson, D G; Heaman, L M; Locock, A JORCID logo; Armstrong, J P
SourceMineralogy and Petrology vol. 112, 2, 2018 p. 653-672,
Alt SeriesNatural Resources Canada, Contribution Series 20200258
PublisherSpringer Wien
Meeting11th International Kimberlite Conference (IKC); Gaborone; BW; September 18-22, 2017
Mediapaper; on-line; digital
File formatpdf
AreaMelville Peninsula
Subjectsgeochronology; geochemistry; igneous and metamorphic petrology; mineralogy; kimberlites; olivine; mantle; Rae Craton; Cambrian
Illustrationslocation maps; sections; plots; variation diagrams; tables
Released2018 08 28
AbstractDetailed 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.

Date modified: