Archean continental crust formed by magma hybridization and voluminous partial melting
Abstract
Archean (4.0–2.5 Ga) tonalite–trondhjemite–granodiorite (TTG) terranes represent fragments of Earth's first continents that formed via high-grade metamorphism and partial melting of hydrated basaltic crust. While a range of geodynamic regimes can explain the production of TTG magmas, the processes by which they separated from their source and acquired distinctive geochemical signatures remain uncertain. This limits our understanding of how the continental crust internally differentiates, which in turn controls its potential for long-term stabilization as cratonic nuclei. Here, we show via petrological modeling that hydrous Archean mafic crust metamorphosed in a non-plate tectonic regime produces individual pulses of magma with major-, minor-, and trace-element signatures resembling—but not always matching—natural Archean TTGs. Critically, magma hybridization due to co-mingling and accumulation of multiple melt fractions during ascent through the overlying crust eliminates geochemical discrepancies identified when assuming that TTGs formed via crystallization of discrete melt pulses. We posit that much Archean continental crust is made of hybrid magmas that represent up to ~ 40 vol% of partial melts produced along thermal gradients of 50–100 °C/kbar, characteristic of overthickened mafic Archean crust at the head of a mantle plume, crustal overturns, or lithospheric peels.
Additional Information
© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Received 03 September 2020; Accepted 15 February 2021; Published 04 March 2021. We thank Ideal Blanco-Quintero, Marcos García-Arias, Gary Stevens, and Jesse Reimink for valuable comments on a preliminary version of the manuscript. We also thank two anonymous reviewers for constructive comments that helped to significantly improve this manuscript. This work was supported in part by a graduate fellowship awarded to JDHM at the Universidad Nacional de Colombia. Data availability: All data used for petrological modeling are provided in Supplementary Information. The software used for phase equilibrium calculations (Theriak-Domino) is available at no cost from http://www.rocks.uni-kiel.de/theriakd/html/down_en.html. Detailed results and additional source code used for PIXELMAPS calculations can be downloaded at https://github.com/jdavidhm90/Partial-melting-and-TTG-production. Author Contributions: JDHM and DHU performed the petrological calculations. JDHM, RMP, and CAZ designed the methodology for batch-melting and melt accumulation. All authors interpreted the results and prepared the manuscript. The authors declare no competing interests.Attached Files
Published - s41598-021-84300-y.pdf
Supplemental Material - 41598_2021_84300_MOESM1_ESM.docx
Supplemental Material - 41598_2021_84300_MOESM2_ESM.xlsx
Supplemental Material - 41598_2021_84300_MOESM3_ESM.pdf
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Additional details
- PMCID
- PMC7933273
- Eprint ID
- 108315
- Resolver ID
- CaltechAUTHORS:20210304-152020591
- Universidad Nacional de Colombia
- Created
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2021-03-04Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field