Journal article

Oxide, sulphide and carbonate minerals in a mantle polymict breccia: Metasomatism by proto-kimberlite magmas, and relationship to the kimberlite megacrystic suite

A Giuliani, VS Kamenetsky, MA Kendrick, D Phillips, BA Wyatt, R Maas

Chemical Geology | Published : 2013

Abstract

Polymict breccias entrained by kimberlites are mantle xenoliths comprising coarse-grained mantle minerals (porphyroclasts) and rock clasts, cemented together by ilmenite, rutile, phlogopite, olivine and minor sulphides. These unusual xenoliths are generally considered to result from ascending primitive/precursor kimberlite magmas that crystallised in the magma conduit at lithospheric mantle depths. To enhance our understanding of these processes, we investigated the oxide, sulphide and carbonate minerals of a new polymict breccia (DU-1) from the Bultfontein Dumps (Kimberley, South Africa).Xenolith DU-1 contains heterogeneous domains of ilmenite-rich breccia surrounded by spinel harzburgite w..

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University of Melbourne Researchers

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Funding Acknowledgements

We thank Alan Greig for help with LA-ICP-MS analyses, and Graham Hutchinson for support with the SEM imaging and EMP analyses at the University of Melbourne. We are also grateful to Karsten Goemann for assistance with FE-SEM work at Central Science Laboratory, University of Tasmania. The manuscript has benefitted from detailed reviews by Bill Griffin and Oded Navon. We also thank Sebastian Tappe for editorial handling. AG's PhD research is supported by an International Australian Postgraduate Award, the 2011 John Hodgson Scholarship, and the 2012 AusIMM Bicentennial Gold Endowment.