Configurational entropy of basaltic melts in Earth's mantle.

Although geophysical observations of mantle regions that suggest the presence of partial melt have often been interpreted in light of the properties of basaltic liquids erupted at the surface, the seismic and rheological consequences of partial melting in the upper mantle depend instead on the properties of interstitial basaltic melt at elevated pressure. In particular, basaltic melts and glasses display anomalous mechanical softening upon compression up to several GPa, suggesting that the relevant properties of melt are strongly pressure-dependent. A full understanding of such a softening requires study, under compression, of the atomic structure of primitive small-degree basaltic melts at their formation depth, which has proven to be difficult.

Hydrogen Incorporation in Plagioclase.

We conducted experiments at high pressure () and temperature () to measure hydrogen solubility in plagioclase (Pl) with a range of compositions (An to An). Experiments were run at 700-850 °C, 0.5 GPa, and close to either the Ni-NiO (NNO) or iron-wüstite (IW) oxygen buffers.