Torsion oscillatory deformation experiments have been performed at high temperatures (600-1170°C) and over a wide range of low frequencies (0.002-20 Hz) on fine-grained gabbronorite samples from the Oman ophiolite in order to determine the shear wave attenuation as a function of temperature and melt fraction. Measurements of internal friction (1/Q) were performed using a forced oscillatory torsion apparatus at small strains.