MINERAL PHYSICS

Strength to put a stop to sinking slabs

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Science  01 May 2015:
Vol. 348, Issue 6234, pp. 537
DOI: 10.1126/science.348.6234.537-e

Tectonic plates plunging toward Earth's core can unexpectedly stop sinking in the middle of the mantle. Marquardt and Miyagi provide a potential explanation involving the abundant mantle mineral ferropericlase. Their x-ray diffraction experiments revealed a large increase in the strength of ferropericlase with increased pressure. This translates to a viscosity increase at mid-mantle depths, providing a rheological barrier that subducted ocean lithosphere cannot easily penetrate. This mechanism of slab stagnation may also explain some of the mantle's well-known chemical heterogeneity.

Nat. Geosci. 10.1038/ngeo2393 (2015).

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