This paper applies the thermal modelling that had been so successful at mid-ocean ridges to sedimentary basins, such as the North Sea. McKenzie modelled a two-stage history, based on his work in the Aegean. Horizontal stretching of the lithosphere first produces a faulted basin, with thinning of the lithosphere; hotter material below moves upwards in response. Then the lower lithosphere cools and subsidence continues, more slowly. As at mid ocean ridges, the thermal structure is a consequence, not a cause. It’s essentially the same problem with different boundary conditions.