NatureComm-2015-MARID.pdf (4.26 MB)
Download fileDid diamond-bearing orangeites originate from MARID-veined peridotites in the lithospheric mantle?
journal contribution
posted on 2023-05-18, 09:31 authored by Giuliani, A, Phillips, D, Woodhead, JD, Vadim KamenetskyVadim Kamenetsky, Fiorentini, ML, Maas, R, Soltys, A, Armstrong, RAKimberlites and orangeites (previously named Group-II kimberlites) are small-volume igneous rocks occurring in diatremes, sills and dykes. They are the main hosts for diamonds and are of scientific importance because they contain fragments of entrained mantle and crustal rocks, thus providing key information about the subcontinental lithosphere. Orangeites are ultrapotassic, H2O and CO2-rich rocks hosting minerals such as phlogopite, olivine, calcite and apatite. The major, trace element and isotopic compositions of orangeites resemble those of intensely metasomatized mantle of the type represented by MARID (mica-amphibole-rutile-ilmenite-diopside) xenoliths. Here we report new data for two MARID xenoliths from the Bultfontein kimberlite (Kimberley, South Africa) and we show that MARID-veined mantle has mineralogical (carbonate-apatite) and geochemical (Sr-Nd-Hf-O isotopes) characteristics compatible with orangeite melt generation from a MARID-rich source. This interpretation is supported by U-Pb zircon ages in MARID xenoliths from the Kimberley kimberlites, which confirm MARID rock formation before orangeite magmatism in the area.
Funding
Australian Research Council
History
Publication title
Nature CommunicationsVolume
6Article number
6837Number
6837Pagination
1-10ISSN
2041-1723Department/School
School of Natural SciencesPublisher
Nature Publishing GroupPlace of publication
United KingdomRights statement
Copyright 2015 Macmillan Publishers LimitedRepository Status
- Open