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Comment on: 'The ascent of kimberlite: Insights from olivine' by Brett R.C. et al. [Earth Planet. Sci. Lett. 424 (2015) 119-131]

Citation

Kamenetsky, VS, Comment on: 'The ascent of kimberlite: Insights from olivine' by Brett R.C. et al. [Earth Planet. Sci. Lett. 424 (2015) 119-131], Earth and Planetary Science Letters, 440 pp. 187-189. ISSN 0012-821X (2016) [Contribution to Refereed Journal]

Copyright Statement

© 2016 Elsevier B.V. All rights reserved.

DOI: doi:10.1016/j.epsl.2016.02.014

Abstract

Brett et al. (2015) proposed a kimberlite factory model that "…involves carbonatitic proto-kimberlite melts preferentially assimilating Opx xenocrysts as they transit the cratonic mantle lithosphere to evolve into silicic-hydrous melts that reach olivine saturation during ascent" (p. 130). A cornerstone of this model is a specific, carbonatitic composition of proto-kimberlite melts ascending through the subcratonic lithospheric mantle "…whereby parental carbonatitic magmas are progressively converted to kimberlite (e.g., Russell et al., 2012, 2013; Bussweiler et al., 2015)" (p. 120). The model by Brett et al. (2015) is based on observations of "the carbonate-sealed cracks" in olivine that "…strongly support to the hypothesis that all kimberlite magmas originate as carbonatitic-melts (e.g., Russell et al., 2012, 2013; Kamenetsky et al., 2013; Pilbeam et al., 2013; Kamenetsky and Yaxley, 2015; Bussweiler et al., 2015)." (p. 129). While the major thrust of the study by Brett et al. (2015) hinges on the premise that the parental kimberlite melt is carbonatitic, the overwhelming majority in the kimberlite community still prefers a carbonated ultramafic/ultrabasic composition for parental kimberlite melts. Thus the suggestion that kimberlites have an initial carbonatite composition is not less than "a paradigm shift" in the kimberlite petrology. It appears that a carbonatite origin for kimberlites has been proposed in many studies that significantly pre-date the publications starting from 2012 that they cite, but which unfortunately are overlooked by Brett et al. (2015). It is, therefore, worth acknowledging the research which has previously advanced this unorthodox idea.

Item Details

Item Type:Contribution to Refereed Journal
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and Metamorphic Petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Kamenetsky, VS (Professor Vadim Kamenetsky)
ID Code:107932
Year Published:2016
Funding Support:Australian Research Council (DP1092823)
Web of Science® Times Cited:7
Deposited By:Earth Sciences
Deposited On:2016-03-31
Last Modified:2017-12-14
Downloads:0

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