Since the recognition  for the importance of continental tectonics in the 80s, instability of the lower crust and mantle lithosphere has been an important focus for solid earth research. Recent seismological, geochemical and geodynamical studies have revealed some indication of the phenomena found in all major continents (e.g., North China Craton, Tibet, the Transantarctic Mountains, North American Cordillera, Atlas Mountains, Eastern European Alps).  In this session, we seek contributions that provide new insights and constraints on the processes that create high and wide mountain ranges/high plateaux adjacent to continental extensional provinces, distinct volcanism or unusually deep seismicity. We are particularly interested in cases that are active, and those that provide a geological record through the time of their evolution.