Cataclasis involves the granulation, crushing, or milling of the original rock, then rigid-body rotation and translation of mineral grains or aggregates before lithification.
[1] Sibson's 1977 classification of fault rocks was the first to include an understanding of the deformation mechanisms involved and all subsequent schemes have been based on this.
[2][3] Fault breccias have been further classified in terms of their origins; attrition, distributed crush and implosion brecciation,[4] and, borrowing from the cave-collapse literature, crack, mosaic and chaotic from their clast concentration.
[5] Mylonite was originally defined as a cataclastic rock but is now understood to have formed mainly by crystal-plastic processes.
Cataclastic rocks form by brittle processes in the upper part of the crust in areas of moderate to high strain, particularly in fault zones.