Thermodynamic constraints on the geometry of melt/solid interfaces require that a texturally equilibrated partial melt respond to changes in mean normal stress through adjustment of the sizes of melt-bearing triple-grain junctions. This dilational response is well-modeled as that of a standard anelastic solid provided that the response rate is limited by solid-state deformation processes attending the dilation rather than by melt flow itself. Using this model, we have analyzed flexural creep data obtained for a fine-grained partial melt comprising a MgSiO3 polycrystalline solid phase in equilibrium with a sodium aluminosilicate melt. The anelastic dilatational (or ''bulk'') viscosity for this two-phase material is nearly an order of magnitude less than its shear viscosity, the latter being determined by diffusional creep. The corresponding modulus that controls the extent of dilatation is several orders of magnitude smaller than the elastic bulk modulus of the two-phase aggregate. Applied to the case of harmonic loading, the model predicts a substantial band-limited dissipation spectrum for dilatation (Q-1K) that would be absent but for the presence of the melt. This creates a large and strong P wave absorption (Q-1P) band for the enstatite material, accompanied by substantial P wave velocity dispersion. Through this enhanced P wave attenuation, the presence of the melt phase suppresses P-to-S velocity ratios and produces equivalent Q values for the two modes. ¿ American Geophysical Union 1993