Kimberlites as Geochemical Probes of Earth’s Mantle

Kimberlites are ultrabasic, Si-undersaturated, low Al, low Na rocks rich in CO2 and H2O. The distinctive geochemical character of kimberlite is strongly influenced by the nature of the local underlying lithospheric mantle. Despite this, incompatible trace element ratios and radiogenic isotope characteristics of kimberlites, filtered for the effects of crustal contamination and alteration, closely resemble rocks derived from the deeper, more primitive, convecting mantle. This suggests that the ultimate magma source is sub-lithospheric. Although the composition of primitive kimberlite melt remains unresolved, kimberlites are likely derived from the convecting mantle, with possible source regions ranging from just below the lithosphere, through the transition zone, to the core–mantle boundary.

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Advances in Isotope Ratio Determination by LA–ICP–MS

LA–ICP–MS has proven to be an extremely important analytical tool within the Earth, environmental, and archaeological sciences. New developments in both instrumentation and methodology now provide the ability to extract age and isotopic tracer information in situ at a variety of scales (from nm to cm), in 2- and 3-dimensions, quickly and cost-effectively, providing considerable analytical flexibility compared to other micro-analytical techniques. Here, we review the current state of the art in laser ablation isotope ratio determination and provide some insights into future developments.

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