Fossil fault zones: significance and applications

Fossil faults are permanently inactive fault zones, preserved and recognized in the geological record of an area by major brittle, semi-brittle, or mylonitic fault rocks, showing significant width and displacement. Applications and purposes of fossil fault researches include, but are not limited to, investigation on seismic faulting, analog model of active faults, metal ore deposits, paleo-path and fluid migration, deformation mechanism and fault migration along-strike and down-dip. These categories involve subsidiary subjects, some of which are relatively new and seem to attract more attention. Fossil faults are a major source of information about past geological processes that were active at some depth in Earth’s lithosphere, and also provide an opportunity for assuming and predicting the future in structural geology. This paper reviews the researches done on fossil faults and their applications since the early 1970s, albeit not always listed as “fossil faults”.