Figure 6.18. Clockwise P-T Path. Hypothetical P-T path for which pressure increases as rocks are buried faster than temperatures can adjust. The maximum pressure is reached when burial stops. The rocks continue to be heated in response to the thickened crust, although pressure starts to fall due to erosion. A maximum temperature is reached as the crust continues to thin. Eventually, the rocks are returned to the surface on this clockwise P-T path.
Click on the "Other Paths" button to see examples of p-T paths for rocks in the same hypotheical terrain that are not buried as as deeply. If the rocks preserve equilibrium mineral assemblages formed at the maximum temperatures of the P-T paths, the "metamorphic field gradient" should be defined by the maximum temperature P-T conditions. Click on the "Medium P/T Series" button to see that the maximum temperatures for this path fit a medium P/T (Barrovian) facies series.
- Metamorphic Rocks: Topics
