Extended Data Fig. 9: Evidence (Fresnel micrograph, Δf ≈ −20 μm) of grain-boundary sliding in specimen M640 (5 GPa, 1,000 °C).
From: Stress-induced amorphization triggers deformation in the lithospheric mantle
The symbols represent markers, which help to visualize the shear (represented by the white arrow). Some shear bands evidenced by the Fresnel contrast are shown by black arrows. Owing to the shape of the grain, the pure shear sliding displacement in the upper part of the grain boundary transforms into opening in the central part.
