The effect of metastable pyroxene on the slab dynamics

Agrusta, R.; van Hunen, J.; Goes, S.

Abstract

Seismic studies show that some subducting slabs penetrate straight into the lower mantle, whereas others seem to flatten near the base of the mantle transition zone. Slab stagnation is often attributed to an increase in viscosity and phase transformations in the olivine system. However, recent mineral physics studies showed that due to extremely low transformational diffusion rates, low-density metastable pyroxene may persist into the transition zone in cool slabs. Here we use a dynamically fully self-consistent subduction model to investigate the influence of metastable pyroxene on the dynamics of subducting oceanic lithosphere. Our results show that metastable pyroxene affects slab buoyancy at least as much as olivine metastability. However, unlike metastable olivine, which can inhibit slab penetration in the lower mantle only for cold, old, and fast slabs, metastable pyroxene is likely to also affect sinking of relatively young and slow slabs.

Citation

Agrusta, R., van Hunen, J., & Goes, S. (2014). The effect of metastable pyroxene on the slab dynamics. Geophysical Research Letters, 41(24), 8800-8808. https://doi.org/10.1002/2014gl062159

• Journal Article Type: Article
• Acceptance Date: Dec 6, 2014
• Online Publication Date: Dec 20, 2014
• Publication Date: Dec 28, 2014
• Deposit Date: Jan 4, 2015
• Publicly Available Date: Jan 22, 2015
• Journal: Geophysical Research Letters
• Print ISSN: 0094-8276
• Electronic ISSN: 1944-8007
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 41
• Issue: 24
• Pages: 8800-8808
• DOI: https://doi.org/10.1002/2014gl062159
• Keywords: Subduction, Metastable pyroxene, Phase transition.
• Public URL: https://durham-repository.worktribe.com/output/1439233