Kimberlite Magmatism and Mantle Petrogenesis

Kimberlite magmatism originates from deep in the Earth’s mantle beneath ancient, stable regions known as cratons, where small‐volume, volatile‐rich melts form by low‐degree partial melting of carbonated and metasomatised mantle sources at depths exceeding 150 km. Rapid exsolution of CO₂ and H₂O drives these buoyant magmas through narrow conduits, entraining mantle xenoliths and occasionally diamonds. Disruption of the cratonic keel by rifting and convective instabilities links kimberlite episodicity to supercontinent cycles, while interaction with lithospheric wall rocks modifies melt composition and controls diamond preservation. Entrainment of xenoliths samples mantle composition, redox conditions and thermal structure, informing models of lithosphere–asthenosphere architecture and carbon fluxes. Advances in thermodynamic models, diffusion chronometry and high‐resolution geochemical analyses are refining estimates of melt evolution and ascent dynamics. By integrating geophysical, petrological and geochemical approaches, current research illuminates the processes governing kimberlite formation, the evolution of the subcontinental mantle and the genesis of diamond deposits.

Research from Nature Portfolio

Recent studies have quantified the mechanistic links between craton rifting and kimberlite episodicity by demonstrating that convective instabilities at steep lithosphere–asthenosphere boundaries formed after continental breakup can undermine cratonic keels and initiate low‐degree partial melting. Modelling shows that these instabilities persist for tens of millions of years, driving pulses of volatile‐rich melt generation. Complementary work has identified high-Mg/Fe olivine in kimberlites as an indicator of minimal mantle metasomatism and a reliable proxy for diamond preservation, revealing that carbonate-rich metasomatism promotes diamond dissolution. Investigations into xenolith transport have introduced the concept of lag time, whereby differences in settling velocities and magma ascent rates bias the depth sampling of erupted mantle fragments, refining interpretations of lithospheric architecture and eruption dynamics.

Kimberlite Magmatism and Mantle Petrogenesis publication trend

The graph below shows the total number of articles in kimberlite magmatism and mantle petrogenesis across all publications each year (not limited to Nature Index journals).

Technical terms

Cr*aton*: An ancient, stable part of the continental lithosphere underlain by a thick, buoyant mantle keel.

Lithospheric mantle: The rigid upper portion of the mantle directly below the crust, forming the base of tectonic plates.

Asthenosphere: The ductile, partially molten zone of the upper mantle beneath the lithosphere that accommodates plate motion.

Partial melting: The process by which only a portion of a solid rock melts, often enriching the melt in volatiles and incompatible elements.

Metasomatism: Chemical alteration of mantle or crustal rocks by fluid or melt percolation, modifying mineralogy and composition.

Xenolith: A fragment of pre-existing rock, often from the mantle, carried to the surface by ascending magma.

Magma ascent rate: The speed at which molten rock rises through the crust, controlled by buoyancy, viscosity and volatile exsolution.

Diffusion chronometry: A method for estimating timescales of magmatic processes by measuring chemical diffusion profiles in minerals.

References

1. Rift-induced disruption of cratonic keels drives kimberlite volcanism. Nature (2023).
2. Diamond preservation in the lithospheric mantle recorded by olivine in kimberlites. Nature Communications (2023).
3. Petrology and geochemistry of Canadian diamonds: An up-to-date review. Earth-Science Reviews (2023).
4. Transport and eruption of mantle xenoliths creates a lagging problem. Communications Earth & Environment (2023).
5. Ascent rate of the Udachnaya-East kimberlite melts from olivine diffusion chronometry. Earth and Planetary Science Letters (2023).
6. Kimberlite genesis from a common carbonate-rich primary melt modified by lithospheric mantle assimilation. Science Advances (2020).