PREFERRED ORIENTATION OF OLIVINE AND ANISOTROPY OF THE OCEANIC LITHOSPHERE

抄録

According to known laboratory experiments of rock deformation, preferred orientation of a mineral is often closely correlated to a dominant slip system in the crystal. A theoretical consideration reveals how the dislocation gliding that is caused by the resolved shear stress on the slip plane rotates the crystal grain in polycrystalline aggregates. A simple principle to determine preferred orientation associated with such a slip-induced rotation is theoretically derived consistently with the observations. The theory applied to the seismic velocity anisotropy in the oceanic lithosphere predicts that young lithospheres should be subject to an extensional force normal to the ridge axis.