Shock Metamorphism

Pressure–temperature fields for shock metamorphism of silicate rocks. Dashed lines represent temperature estimates based on theoretical considerations by Davies (1972). Image Modified from Source: MaPS Volume 53, Issue 1

Metamorphism produced by hypervelocity impact between objects of substantial size moving at cosmic velocity (at least several kilometers per second). Kinetic energy is converted into seismic and heat energy almost instantaneously, yielding pressures and temperatures far in excess those in normal terrestrial metamorphism. On planetary bodies with no atmosphere, smaller impacting bodies (even micrometeorites) can produce shock metamorphic effects as observed in meteorites. Observed effects include planar deformation features (PDFs), diaplectic glass, and melting. Effects are observed in different minerals at different pressures.