Journal article
Thallium isotopic composition of phlogopite in kimberlite-hosted MARID and PIC mantle xenoliths
A Fitzpayne, J Prytulak, A Giuliani, J Hergt
Chemical Geology | ELSEVIER | Published : 2020
Abstract
MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks are rare mantle xenoliths entrained by kimberlites. Their high phlogopite modes (15 to ∼100 vol.%) and consequent enrichments in alkali metals and H2O suggest a metasomatic origin. Phlogopite also has high concentrations (>0.2 μg/g) of thallium (Tl) relative to mantle abundances (<3 ng/g). Thallium isotope ratios have proven useful in tracing the input of Tl-rich materials, such as pelagic sediments and altered oceanic crust, to mantle sources because of their distinct isotopic compositions compared to the peridotitic mantle. This study presents the first Tl isotopic compositions of well-charact..
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Awarded by University of Melbourne
Funding Acknowledgements
We thank De Beers Consolidated Mines, the J. J. Gurney Upper Mantle Room Collection (University of Cape Town), and Simon Shee for kindly providing access to the studied samples, and Jock Robey for his assistance during fieldwork in the Kimberley region. We also wish to thank Barry Coles for his help throughout the analytical sessions, as well as Katharina Kreissig, Roland Maas, and Serene Paul for their assistance and support in the clean labs. This manuscript benefited from the constructive comments of two anonymous reviewers, as well as the efficient editorial handling of Catherine Chauvel. AF's PhD research has been supported by the Gilbert Rigg Scholarship from the University of Melbourne, and this project was specifically supported by further funding from the George Sweet and Baragwanath scholarships, as well as a Science Abroad Travelling Scholarship, all from the University of Melbourne. This manuscript was written with the support of the Albert Shimmins Fund from the University of Melbourne. This is publication 48 from the Kimberlites and Diamonds Research Group (https://kimberlitesdiamonds.org/). AG acknowledges funding from the Swiss National Science Foundation through an Ambizione fellowship (PZ00P2_180126/1).