pyrometamorphism (py''-ro-met''-a-mor'-phism). (a) Metamorphic changes taking place without the action of pressure or water vapor, at temperatures near the melting points of the component minerals; it is a local, intense type of thermal metamorphism, resulting from the unusually high temperatures at the contact of a rock with magma, e.g. in xenoliths (Turner, 1948). Cf: igneous metamorphism. (b) "Metamorphism" caused by lightning strikes and burning coal seams.