When this type of rock is backrotated with respect to shear direction, they may form mica fish or larger foliation fish.
A 1977 paper by Sibson classified this type of rock as those formed on the QP side of the QP/EF transition. When this type of rock is backrotated with respect to shear direction, they may form mica fish or larger foliation fish. The name for these rocks was introduced by Charles Lapworth to describe the Scottish Moine Thrust Belt, where layers of this type of rock reach more than 100 meters in thickness. This type of rock may form via dynamic metamorphism when it occurs below about 10 kilometers because frictional heating is dispersed enough to prevent melting, which would form (*) pseudotachylite. These fault rocks are both cohesive and strongly schistostic unlike breccias and gouges, and they are distinct from cataclasites, which also form at sites of high shear stress but form due to grain crushing. For 10 points, name this type of highly foliated metamorphic rock whose grain size is reduced primarily by ductile deformation.
A 1977 paper by Sibson classified this type of rock as those formed on the QP side of the QP/EF transition.
mylonite [prompt on fault rocks before mentioned]