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Date
2023-11Type
- Review Article
Abstract
Kimberlites are volcanic rocks enriched in CO2 and H2O and derive from the deepest-sourced melts (up to 300 km) that reach Earth's surface. The mantle processes that generate such deep melts and allow them to traverse through thick (>= 150 km), cold lithosphere carrying dense mantle fragments, such as xenoliths and diamonds, are debated. In this Review, we explore the composition, formation and evolution of kimberlite melts and the mechanisms of their ascent. Both deep-mantle plumes and shallower convective motions linked to lithospheric extension could trigger kimberlite melting by bringing upwelling mantle rocks to depths above Fe-metal stability (similar to 160-250 km depth). Despite the CO2 enrichment in kimberlite melts, their sources are peridotites not necessarily enriched in carbon. Kimberlite primary melts are transitional between silicate and carbonate compositions and evolve towards increasing silica and lower CO2 concentrations during ascent, while concurrently interacting with the lithospheric mantle. These ascent processes promote the exsolution of CO2-H2O fluids during decompression, a prerequisite for the fast ascent (up to tens of metres per second) of kimberlite magmas. Key unresolved questions include the volatile and alkali budget of kimberlites and their mantle sources; their relationship with 'superdeep' diamonds; and their potential link to plumes from the core-mantle boundary. Show more
Publication status
publishedExternal links
Journal / series
Nature Reviews Earth & EnvironmentVolume
Pages / Article No.
Publisher
NatureOrganisational unit
03592 - Schmidt, Max / Schmidt, Max
03592 - Schmidt, Max / Schmidt, Max
Funding
180126 - A new understanding of kimberlite magmas from deep Earth to diamond mines (SNF)
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