Vibrational spectroscopy of minerals at pressure: application to the mantle

Vibrational spectroscopy is a powerful tool to investigate the composition and thermal state of Earth's interior, as well as to study the basic properties of materials. Infrared (IR) data can be collected as a function of pressure (up to 100 GPa) from microsamples in a diamond anvil cell. Correct interpretation of these high-pressure spectra requires complete characterization of the sample at ambient conditions. Such data provide information on bonding and structure of materials, and allow calculation of thermodynamic and elastic properties, as functions of pressure and temperature, which are needed to establish the mantle geotherm. Current research involves measurement of IR spectra of phases in the MgO-FeO-SiO₂ system and their analogues as a function of pressure. Future endeavors will concern modification of the experiments to attain high temperatures during compression. -Author