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A mantle origin for high-Sr late Archean tonalite-trondhjemite granodiorite suites

Spencer, Laura M., Smithies, R. H., Williams, H. M., Nebel, O., Parkinson, I. J., Lissenberg, C. J. ORCID: https://orcid.org/0000-0001-7774-2297 and Millet, Marc-Alban ORCID: https://orcid.org/0000-0003-2710-5374 2026. A mantle origin for high-Sr late Archean tonalite-trondhjemite granodiorite suites. Geology 54 (5) , pp. 440-445. 10.1130/g54038.1

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Abstract

Tonalite-trondhjemite-granodiorite (TTG) suites are the dominant constituent of Archean continental crust and as such are key in understanding the origin of Earth’s continents. Their geochemical variability is typically thought to reflect metabasite melting over a range of pressures (1 to ≥2 GPa). Recent studies challenge this interpretation and have proposed that a subset of “high-pressure” TTGs with very high Sr concentrations and Sr/Y instead formed by fractional crystallization of metasomatized mantle-derived sanukitoid magmas. Here we use titanium stable isotope variations to demonstrate that Neoarchean high-Sr TTGs from the Yilgarn craton (Western Australia) are equivalent to evolved sanukitoids, whereas other Neoarchean Yilgarn TTGs are best explained by metabasite partial melting in the garnet stability field, hence recording contemporaneous formation of TTGs by two distinct mechanisms. High-Sr TTGs are near ubiquitous in Archean cratons globally, became abundant after ca. 3 Ga, and most are spatially and temporally associated with sanukitoids. These observations point to widespread formation of TTGs from mantle-derived magmas in the late Archean and may reflect a change in geodynamic processes at this time.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Schools > Earth and Environmental Sciences
Publisher: Geological Society of America
ISSN: 0091-7613
Date of First Compliant Deposit: 3 March 2026
Date of Acceptance: 22 January 2026
Last Modified: 07 May 2026 15:00
URI: https://orca.cardiff.ac.uk/id/eprint/185442

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