Reconstructed 3-D view of the melt geometry in partially molten dunite from field emission scanning electron microscope images. The 3-D image reveals that the thin layers seen with 2-D imaging (below) are wetted two-grain boundaries. The melt distribution is not static, but dynamically controlled by grain growth, reslulting in a mixture of wetted and melt-free grain boundaries. Higher resolution image here.

High resolution FESEM image of the same partially molten olivine samples as above. Thin layers of melt wetting two-grain boundaries are indicated by double arrowheads. The arrows point to small triple junctions one μm or less in size. The white dots in the inset denote melt-free grain boundaries. Higher resolution image here.