Diagram from the study
Occasional volcanic eruptions and magmatic intrusions bring a cargo of minerals up from the mantle root underlying the ancient crust of the Kimberley Craton. Analysis of the mantle-derived crystals carried by these magmas can be used to determine the temperature gradient and geochemical composition of this thick section of sub-continental lithosphere through time. The results reveal long-term stability and a layered structure consistent with formation of the crust by extraction of melt from the upper layers, together with addition of deeper material to the root by past episodes of subduction. Credit: Sudholz et al. [2023], Figure 12
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Geochemistry, Geophysics, Geosystems

The Kimberley Craton in Western Australia is a classic locality for kimberlite (coincidentally named for a different place called Kimberley, in South Africa), a mantle-derived igneous rock famous for delivering diamonds from the mantle lithosphere to near the surface where they can be mined. This ancient core of the Australian continent is also an excellent example of the long-lived and stable continental structures that survive the abuses of plate tectonics for billions of years.

Sudholz et al. [2023] provide a comprehensive dataset of compositions of mantle-derived minerals from kimberlites scattered across the Craton and through time. Their analysis of the pressure-temperature conditions and geochemical characteristics recorded by each pyroxene and garnet crystal enables a reconstruction of the layered composition and structure of the Craton through time. This reveals the thickness, geothermal gradient, and history of melt extraction or addition from each layer of the mantle lithosphere.

Citation Sudholz, Z. J., Jaques, A. L., Yaxley, G. M., Taylor, W. R., Czarnota, K., Haynes, M. W., et al. (2023). Mapping the structure and metasomatic enrichment of the lithospheric mantle beneath the Kimberley Craton, Western Australia. Geochemistry, Geophysics, Geosystems, 24, e2023GC011040. https://doi.org/10.1029/2023GC011040

—Paul Asimow, Editor, G-Cubed

Correction, 26 October 2023: The first sentence of the text was revised to better classify the Kimberley Craton.

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