Strong plates enhance mantle mixing in early Earth

Agrusta, Roberto; van Hunen, Jeroen; Goes, Saskia

Abstract

In the present-day Earth, some subducting plates (slabs) are flattening above the upper–lower mantle boundary at ~670 km depth, whereas others go through, indicating a mode between layered and whole-mantle convection. Previous models predicted that in a few hundred degree hotter early Earth, convection was likely more layered due to dominant slab stagnation. In self-consistent numerical models where slabs have a plate-like rheology, strong slabs and mobile plate boundaries favour stagnation for old and penetration for young slabs, as observed today. Here we show that such models predict slabs would have penetrated into the lower mantle more easily in a hotter Earth, when a weaker asthenosphere and decreased plate density and strength resulted in subduction almost without trench retreat. Thus, heat and material transport in the Earth’s mantle was more (rather than less) efficient in the past, which better matches the thermal evolution of the Earth.

Citation

Agrusta, R., van Hunen, J., & Goes, S. (2018). Strong plates enhance mantle mixing in early Earth. Nature Communications, 9, Article 2708. https://doi.org/10.1038/s41467-018-05194-5

• Journal Article Type: Article
• Acceptance Date: Jun 13, 2018
• Online Publication Date: Jul 13, 2018
• Publication Date: Jul 13, 2018
• Deposit Date: Jun 15, 2018
• Publicly Available Date: Jun 26, 2018
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Article Number: 2708
• DOI: https://doi.org/10.1038/s41467-018-05194-5
• Public URL: https://durham-repository.worktribe.com/output/1328905
• Related Public URLs: https://drive.google.com/open?id=12kBhVr8v2JcEtKhCMqrhD8clsVUwM8x4