Some examples of P-T-t paths occurring in different geodynamic contexts. ------------ The P T t Path is characteristic of the Geodynamic Context (see below) in which that rock was formed. 1 et 2 : rocks at the top of the continental crust overlapped during a continent-continent collision and rising at variable speeds (v1>v2).  3: Rock at the bottom of the same crust. 4: magmatic (basic) rock emplaced and cooling at the base of a continental crust or under an island arc. A new orogenic event is needed to bring rocks 3 and 4 back to the surface.  5: gabbro emplaced and cooling in the oceanic crust.  6: thickening coupled with magmatic intrusions.  The solid line portions of these paths are the only ones likely to be preserved by the parageneses of the rocks. Consequently the preserved portions of paths 3 and 4 make it difficult to distinguish between the two. GLs : steady state geotherm inside the stable Lithosphere.

The position of rocks 1, 2, 3 and 6 in this figure corresponds to the peak pressure of their respective paths in the PT diagram above.