A deep fault is a large-scale fault zone that extends to great depths and is active for long periods of time. Deep faults can be up to thousands of kilometres long and may cut through the crust or even through the lithosphere. Chinese scientists have categorised deep faults as crustal faults and lithospheric faults. Cataclastic rocks (brittle tectonites) and mylonites (ductile tectonites) develop along deep faults, indicating that they were formed during different stages and at different depths. Deep faults affect the thicknesses of the adjacent deposits, the lithofacies and rock formations; therefore, they affect the geological evolution of the region. Deep basic-ultrabasic rock intrusions and intense dynamic metamorphic zones are always located along deep faults. Because deep faults have significant effects on the surrounding region, they are often associated with geophysical anomalies.