HIGH-PRESSURE MINERAL SCIENCES: FROM ALCHEMY TO THE MODERN ERA

Francis Birch pointed out a half century ago, based on the observations of the Earth's interior at the time and the limited experimental data then available, that the constituent materials likely transform at depth to forms that are uncommon near the surface. It is now established that the effects of high P-T conditions on mineral behavior can be much more significant than previously thought and can give rise to a variety of unexpected and still not fully understood phenomena. In addition to providing mineralogical underpinning for numerous geophysical observations from the deep crust to the core, technical and conceptual advances in high-pressure mineral sciences have contributed significantly to numerous other disciplines. There is now a need to move to more extreme conditions to understand the behavior of larger bodies in this solar system and beyond. Diamond was first convincingly synthesized over half a century ago in large presses; there is now a major effort to produce superior material by chemical vapor deposition for a broad range of applications. The high-temperature cuprate-based superconductors, all based on the perovskite structure and first synthesized as polyphase assemblages, were advanced using microanalytical methods developed for high-pressure mineral physics. Studies of new phases of ice and ice compounds important for nebular evolution and planetary environments are leading to potential gas-storage materials for energy transport. Mineral reactions studied in situ at high pressure are leading to new insights into the generation of hydrocarbon reservoirs. Methods developed for high-pressure mineralogy are being used to uncover the limits of life under extreme conditions. A new world of nanomineralogy is appearing with the use of submicron- to nanometer-scale diffraction and spectroscopy inspired by high pressure. Looking to the next half century, these emerging areas at the confluence of mineralogy and materials science will be made possible by the development of the next generation of high P-T techniques and continued advances in synchrotron, neutron, and laser facilities.