Reply to: "Recycled" volatiles in mantle derived diamonds - Evidence from nitrogen and noble gas isotopic data | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Reply to: "Recycled" volatiles in mantle derived diamonds - Evidence from nitrogen and noble gas isotopic data

Publication Type:

Journal Article

Source:

Earth and Planetary Science Letters, Volume 252, Issue 1-2, p.220-222 (2006)

ISBN:

0012-821X

URL:

http://www.sciencedirect.com/

Keywords:

diamond-; stable-isotopes; rare-gases; mantle-; subduction-

Abstract:

In a reinterpretation of our published rare gas data obtained on polycrystalline diamonds from the Orapa kimberlite (Botswana) [C.E. Gautheron, P. Cartigny, M. Moreira, J.W. Harris and C.J. Allegre, Evidence for a mantle component shown by rare gases, C. and N isotopes in polycrystalline diamonds from Orapa (Botswana), Earth Planet. Sci. Lett., 240 (2005) 559-572.], Mohapatra and Honda [R.K. Mohaparra, and M. Honda, "Recycled" volatiles in mantle derived diamonds-evidence from nitrogen and noble gas isotopic data, Earth Planet. Sci. Lett., this issue, 2006.] claim that mixing between a-priori defined proportions of subducted seawater, subducted recycled oceanic crust, recycled sediments, air and the mantle would be more appropriate to account for the observations. This view sharply contrasts with our conclusions that the chemical and isotope compositions of rare gases record diamond formation from mantle-derived fluid(s) together with mantle post-crystallization radiogenic/nucleogenic/fissiogenic ingrowth and preferential diffusion of the lightest atoms out of the diamonds in the mantle [C.E. Gautheron, P. Cartigny, M. Moreira, J.W. Harris and C.J. Allegre, Evidence for a mantle component shown by rare gases, C and N isotopes in polycrystalline diamonds from Orapa (Botswana), Earth Planet. Sci. Lett., 240 (2005) 559-572.]. We present here reasons why the alternative view of Mohapatra and Honda [R.K. Mohapatra and M. Honda, "Recycled" volatiles in mantle derived diamonds-evidence from nitrogen and noble gas isotopic data, Earth Planet. Sci. Lett., this issue, 2006.] is not supportable. (c) 2006 Elsevier B.V. All rights reserved.

Notes:

Univ Paris 11, CNRS, UMR 8148, UMR Interact & Dynam Environm Surface, F-91405 Orsay, France; Univ Paris 07, Inst Phys Globe, CNRS, UM 7579,Lab Geochim & Cosmochim, F-75252 Paris 05, France; Univ Paris 07, Inst Phys Globe, CNRS, UMR 7047,Lab Geochim Isotopes Stables, F-75252 Paris 05, France; Univ Glasgow, Dept Geog & Earth Sci, Glasgow G12 8QQ, Lanark, ScotlandEditorial-MaterialEnglish