A detachment fault is a low-angle normal fault that typically separates highly deformed rocks in its hanging wall from less deformed rocks in its footwall. These faults are often associated with large-scale extensional tectonics and can be linked to the formation of metamorphic core complexes. Detachment faults are significant in understanding the tectonic evolution of extensional terrains.
Reference: Wernicke, B. (1981). “Low-Angle Normal Faults in the Basin and Range Province: Nappe Tectonics in an Extending Orogen.” Nature, 291(5810), 645-648.