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The effect of metastable pyroxene on the slab dynamics
Author(s) -
Agrusta Roberto,
Hunen Jeroen,
Goes Saskia
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl062159
Subject(s) - pyroxene , geology , olivine , metastability , slab , mantle (geology) , subduction , lithosphere , transition zone , petrology , geophysics , geochemistry , seismology , tectonics , physics , quantum mechanics
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.