Pseudotachylite is a fault rock that has the appearance of the basaltic glass, tachylyte. It is generally found either along fault surfaces, often as the matrix to a breccia, or as veins injected into the walls of the fault. In most cases there is good evidence that the pseudotachylite formed by frictional melting of the wall rocks during rapid fault movement associated with a seismic event. This has caused them to be termed "fossil earthquakes".

References

• Sibson, R.H., 1975. Generation of pseudotachylite by ancient seismic faulting. Geophysical Journal of the Royal Astronomical Society 43, 775– 794.

External links

• Pseudotachylites, Vredefort Dome, 1 September 2002, Caltech Paleomag trip: South Africa.