| Metamorphism can occur either when a rock moves from one position to another along a single geotherm or when the geotherm itself changes form. |
| The magnitude of the geothermal gradient thus varies with the shape of the geotherm. |
| The specific shape of the geotherm beneath any location on Earth is a function of its corresponding local tectonic regime. |
| The dotted line may be assumed to be a geotherm having a temperature of viscosity. |
| The batch of mantle ascends adiabatically, whereas the geotherm becomes conductive. |
| The anomalously high temperatures are assumed to extend down from the surface to 200 km depth, where they join the normal geotherm. |
