Preferred orientation of experimentally deformed pyrite measured by means of rieutron diffraction

Neutron diffraction texture goniometry indicates that naturally deformed polycrystalline pyrite ores from Mt. Lyell (Tasmania) and Degtiarka (Ural Mountains) have weak lattice preferred orientations. During experimental deformation i volving dislocation flow at elevated temperatures and pressures, these initial fabrics have been modified to produce new lattice preferred orientations. Polycrystalline pyrite form Mt. Lyelt (B-l) has an initial < l l l>- f ib re texture perpendicular to a grain-size layering. After 24 % shortening perpendicular to the < l l l>- f ib re axis at 700 ~ a new, but weak <100> texture has developed parallel to the shortening axis. The Degtiarka pyrite (PN-6) initially has two weak fibre components. The somewhat stronger component isa < 100>-fibre texture, similar to that in the experimentally deformed B-1 pyrite. The other one is a < l l l>- f ib re texture similar to the intital B-1 preferred orientation. After 30 % shortening oblique to both initial fibre axes at 600 ~ weak < 110>- and < 111>-fibre textures have developed. The experimentally produced fabrics have developed uring deformation involving dislocation flow, dynamic recrystallisation a d some microcracking. Intergranular sliding may also have been involved. Differences between lattice preferred orientations developed in the 600 ~ and 700 ~ experiments are interpreted to indicate