Melt migration in a silicate liquid-olivine system: An experimental test of compaction theory

To investigate the kinetics of porous flow in partially molten peridotite, a melt migration couple – formed from a disc of fine-grained olivine plus ∼15% of a synthetic K-Al silicate glass and a disc of poly crystalline olivine – was heated at 1255°C under a confining pressure of 300 MPa for 2 hr. Driven by capillary forces, silicate liquid in the source disc infiltrates along three-grain junctions into the sink disc. To analyze the resulting melt migration profile in terms of compaction theory, the equations developed by McKenzie [1984] to describe porous flow of a liquid in a deformable matrix were modified by replacing the buoyancy force term with a capillary force term. The governing equations were then solved numerically with the initial and boundary conditions specified by the experimental design. Comparison of the melt migration profile obtained from the experiment with those generated by numerical simulation demonstrates that compaction theory provides a good description of the experimental results provided that the permeability of these solid-liquid materials increases linearly with increasing liquid fraction.