143461 - Kimberlite genesis from a common carbonate-rich primary melt modified by lithospheric mantle assimilation.pdf (235.97 kB)
Kimberlite genesis from a common carbonate-rich primary melt modified by lithospheric mantle assimilation
journal contribution
posted on 2023-05-20, 22:00 authored by Giuliani, A, Pearson, DG, Soltys, A, Dalton, H, Phillips, D, Foley, SF, Lim, E, Karsten GoemannKarsten Goemann, Griffin, WL, Mitchell, RHQuantifying the compositional evolution of mantle-derived melts from source to surface is fundamental for constraining the nature of primary melts and deep Earth composition. Despite abundant evidence for interaction between carbonate-rich melts, including diamondiferous kimberlites, and mantle wall rocks en route to surface, the effects of this interaction on melt compositions are poorly constrained. Here, we demonstrate a robust linear correlation between the Mg/Si ratios of kimberlites and their entrained mantle components and between Mg/Fe ratios of mantle-derived olivine cores and magmatic olivine rims in kimberlites worldwide. Combined with numerical modeling, these findings indicate that kimberlite melts with highly variable composition were broadly similar before lithosphere assimilation. This implies that kimberlites worldwide originated by partial melting of compositionally similar convective mantle sources under comparable physical conditions. We conclude that mantle assimilation markedly alters the major element composition of carbonate-rich melts and is a major process in the evolution of mantle-derived magmas.
History
Publication title
Science AdvancesVolume
6Issue
17Article number
eaaz0424Number
eaaz0424Pagination
1-10ISSN
2375-2548Publisher
American Association for the Advancement of SciencePlace of publication
United StatesRights statement
Copyright 2020 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S.Government Work. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/Repository Status
- Open