[met-uh-mawr-fiz-uh
m] 
| 1. | Geology. a change in the structure or constitution of a rock due to natural agencies, as pressure and heat, esp. when the rock becomes harder and more completely crystalline. |
| 2. | Archaic. metamorphosis. |
| met·a·mor·phism (mět'ə-môr'fĭz'əm) n. The process by which rocks are altered in composition, texture, or internal structure by extreme heat, pressure, and the introduction of new chemical substances. [metamorph(ic) + -ism.] |
| metamorphism (mět'ə-môr'fĭz'əm) Pronunciation Key
The process by which rocks are changed in composition, texture, or structure by extreme heat and pressure. ◇ In prograde metamorphism metamorphic rocks that were formed under low pressure and temperature conditions undergo a second metamorphic event in which they are exposed to higher pressures and temperatures. ◇ In retrograde metamorphism metamorphic rocks that were formed under high pressure and temperature conditions undergo a second metamorphic event in which they are exposed to lower pressures and temperatures. See more at contact metamorphism, regional metamorphism. |
