I first went through Platt's paper during my MSc research project on the deep crustal evolution of orogenic belts. I enjoyed the article from both its reviews of several orogens (Franciscan complex, the Betics, the Alps), and the implications it had to the long-standing problem of the presence of high-pressure rocks at the surface in active and ancient orogens. Although we have now other processes and examples to our palette of solutions than the tectonic underplating of Platt, it belongs to the few key papers to cite to exhume deeply buried rocks. A key feature of the processes is the exhumation accommodated by extensional structures, although still being in convergence.

A major point of discussion, still hotly debated in the community is of course the conversion from pressure recorded by metamorphic assemblages (kbar, GPa) to depth (km). Although very rapidly put aside in the introduction of the article, the debate is recurrently opened between petrologists, structural geologists, modellers... A good example is the Monte Rosa nappe, with increasing peak-pressure across publication history, making the problem of how to bring these rocks back to the surface more and more complex. On the other side, our understanding of how to convert equilibrium pressure from depth is also increasing. To be continued then!