Journal article

Origin of complex zoning in olivine from diverse, diamondiferous kimberlites and tectonic settings: Ekati (Canada), Alto Paranaiba (Brazil) and Kaalvallei (South Africa)

Emilie Lim, Andrea Giuliani, David Phillips, Karsten Goemann



Olivine in kimberlites can provide unique insights into magma petrogenesis, because it is the most abundant xenocrystic phase and a stable magmatic product over most of the liquid line of descent. In this study we examined the petrography and chemistry of olivine in kimberlites from different tectonic settings, including the Slave craton, Canada (Ekati: Grizzly, Koala), the Brasilia mobile belt (Limpeza-18, Tres Ranchos-04), and the Kaapvaal craton, South Africa (Kaalvallei: Samada, New Robinson). Olivine cores display a wide range of compositions (e.g., Mg# = 78–95). The similarity in olivine composition, resorption of core zones and inclusions of mantle-derived phases, indicates that most ..

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Awarded by Australian Research Council through a Discovery Early Career Research Award (DECRA)

Funding Acknowledgements

We acknowledge provision of samples from the Ekati mine by BHP Billiton, and permission obtained from Dominion Diamond Mines ULC to publish our results. Samples from Limpeza-18, Tres Ranchos-04, and Samada were generously provided by the De Beers Group, while the New Robinson kimberlite was sourced in the John J. Gurney Upper Mantle Room Collection housed at the University of Cape Town. We would like to thank Graham Hutchinson for his aid with SEM and EPMA analyses at the University of Melbourne. Thoughtful reviews by Nick Arndt and Curtis Brett and the editorial handling by Phil Janneyand Lutz Nasdala improved the final manuscript. This research was supported by the Australian Research Council through a Discovery Early Career Research Award (DECRA) to AG (grant n. DE-150100009). This is publication 32 from the Kimberlites and Diamonds Research Group at the University of Melbourne, also listed as contribution 1173 from the ARC Centre of Excellence for Core to Crust Fluid Systems and 1234 from the GEMOC Key Centre.