Interfacial energies in the olivine basalt system.

Interfacial energies are examined for the olivine-basalt system. The dihedral angle between melt and two solid grains misoriented by 0.2% is approx 170o; this angle, combined with a calculated energy for the low-angle grain boundary, yields a solid-liquid interfacial energy of 500+ or -200erg/cm². Thermal etching of low-angle grain boundaries yields a surface energy for the (010) surface of olivine crystals of 1600+ or -300erg/cm². The contact angle between basalt melt and crystalline olivine is a factor of 3-10 greater on (100) surfaces than on other surfaces. This anisotropy in wetting behavior is probably due to anisotropy in both the solid-liquid interfacial energy and the solid-vapor interfacial energy of the olivine crystals.-Authors