Oxidized iron in garnets from the mantle transition zone

Spin transition zone in Earth's lower mantle.

Mineral properties in Earth's lower mantle are affected by iron electronic states, but representative pressures and temperatures have not yet been probed. Spin states of iron in lower-mantle ferropericlase have been measured up to 95 gigapascals and 2000 kelvin with x-ray emission in a laser-heated diamond cell. A gradual spin transition of iron occurs over a pressure-temperature range extendin...

S velocity reversal in the mantle transition zone

Water-induced convection in the Earth’s mantle transition zone

[1] Water enters the Earth’s mantle by subduction of oceanic lithosphere. Most of this water immediately returns to the atmosphere through arc volcanism, but a part of it is expected as deep as the mantle transition zone (410–660 km depth). There, slabs can be deflected and linger before sinking into the lower mantle. Because it lowers the density and viscosity of the transition zone minerals (...

Slab dehydration in the Earth's mantle transition zone

Because of the high water solubility in wadsleyite and ringwoodite, the mantle transition zone is possibly a large water reservoir. The potentially high water content of the Earth's mantle transition zone is a key element of several global mantle dynamic models. Nevertheless, to keep the transition zone relatively wet, the tendency for convection to distribute water over the entire mantle has t...

Reactive infiltration of hydrous melt above the mantle transition zone

[1] Seismic studies repeatedly image a low‐velocity layer overlying the mantle transition zone in tectonic settings ranging from subduction zones to continental cratons. This layer has been hypothesized to result from the presence of a dense partial melt formed by dehydration melting as relatively wet transition zone material is advected by convection currents into the low‐water‐solubility uppe...