- 1MOE Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China
- 2Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- 3Department of Earth Sciences, Durham University, Durham DH1 3LE, UK
- 4State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
The Archean mantle redox state played an important role in degassing of the Earth's interior and thus influenced atmospheric oxygen levels of the early Earth. But it is unclear if any parts of the uppermost mantle were significantly oxidized by a certain point in the Archean. Here, we investigate oxygen fugacity (fO2) of Archean (> 2535–2517 Ma) peridotites in the North China Craton. Petrology and geochemistry reveal that they experienced strong Neoarchean subduction-related metasomatism. These Neoarchean subduction-metasomatized peridotites record fO2 of ΔFMQ +1.3 ± 0.4 (SD) [relative to the fayalite-magnetite-quartz (FMQ) buffer], which are more oxidized than the Archean ambient mantle, but similar to the modern sub-arc mantle. We propose that this Neoarchean rise of mantle oxidation in the North China Craton was induced by plate subduction, during which the Neoarchean sub-arc mantle in the North China Craton could have been metasomatized and oxidized, and its oxygen fugacity was increased. This process may have had connections with the Great Oxidation Event in the Early Proterozoic.
How to cite: Wang, C., Wu, Z., Allen, M. B., Tang, M., Chen, Y., Jia, L., and Song, S.: Rise of mantle oxidation by Neoarchean subduction in the North China Craton, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20570, https://doi.org/10.5194/egusphere-egu25-20570, 2025.
