An Introduction to Metamorphic Petrology

Much of the material in this book so far has skirted around the problem of how quickly metamorphic rocks form and how long metamorphism lasts. Regional metamorphism can be thought of as taking place in a metamorphic cycle, involving burial, heating, exhumation and cooling. The question of ‘how long’ a metamorphic cycle takes from start to finish may be determined either directly or indirectly. Indirect methods involve calculations of how long it takes for rocks to heat up, cool down, or be buried or exhumed. Based on the thermal properties of rocks, indirect approaches have been used for many years to calculate the rates of heating and cooling associated with igneous intrusions.