Hoare, Liam, Rzehak, Laura J. A., Kommescher, Sebastian, Jansen, Moritz, Rosing, Minik T., Thorsten, Nagel, Millet, Marc-Alban  ORCID: https://orcid.org/0000-0003-2710-5374, Hoffmann, J. Elis and Fonseca, Raul O. C.
2023.
Titanium isotope constraints on the mafic sources and geodynamic origins of Archean crust.
Geochemical Perspectives Letters
28
, pp. 37-42.
10.7185/geochemlet.2342
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Abstract
The timing and formation of Earth’s first continents during the Archean are subjects of significant debate. By examining titanium isotope variations in Archean Tonalite-Trondhjemite-Granodiorite (TTG) rocks and using advanced thermodynamic modelling, we can narrow down the processes involved and emphasise the role of mafic precursor compositions. In our study of Eoarchean Isua metabasalts and Itsaq tonalites in southern West Greenland, we observed a pattern of increasing Ti isotope enrichment with higher SiO2 content, resembling the compositions found in modern subduction zone rocks. Our modelling suggests that the Ti isotope variations in TTGs can be best explained by a combination of partial melting of low TiO2 metabasalts and subsequent crystallisation of tonalitic magmas, resulting in heavier Ti isotopes. This means that Ti isotopes help us distinguish the contributions of various mafic sources and fractional crystallisation during TTG formation. In the case of Itsaq tonalites and many other Eoarchean TTGs, low TiO2 tholeiitic metabasalts with arc-like characteristics likely represent the mafic source rocks, suggesting the formation of some of Earth’s earliest continental crust within a proto-subduction zone setting.
| Item Type: | Article |
|---|---|
| Date Type: | Publication |
| Status: | Published |
| Schools: | Earth and Environmental Sciences |
| Additional Information: | Corrigendum Correction to: Geochemical Perspectives Letters 28, 37–42, doi: 10.7185/geochemlet.2342, published 22 December 2023. Due to an oversight by the authors, the affiliation with the University of Cologne was not properly attributed to two co-authors of the manuscript: L. Rzehak and S. Kommescher. Additionally, Carsten Münker (University of Cologne) and Kristoffer Szilas (University of Copenhagen) should have been acknowledged for granting sample access, with Carsten Münker also providing laboratory access during the very preliminary stages of the project to L. Rzehak and S. Kommescher. These omissions have been rectified, and the author affiliation and acknowledgements sections of the manuscript now reflect these necessary changes, as detailed below. • The affiliation “Institut für Geologie und Mineralogie, Universität Zu Köln, Zülpicher Str. 49b, 50674, Cologne, Germany” has been added as a secondary affiliation to authors L. Rezhak and S. Kommescher. The numbering of other author affiliations has been updated accordingly. • The following sentence has been added to the acknowledgements: “We thank Carsten Münker and Kristoffer Szilas for providing access to additional samples, and in the case of the former, access to laboratory facilities at the University of Cologne during the preliminary stages of this project.” |
| Publisher: | European Association of Geochemistry |
| ISSN: | 2410-339X |
| Related URLs: | |
| Date of First Compliant Deposit: | 10 November 2023 |
| Date of Acceptance: | 6 November 2023 |
| Last Modified: | 07 May 2024 09:33 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/163820 |
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