Structural properties of sodium-rich carbonate-silicate melts: An in-situ high-pressure EXAFS study on Y and Sr

摘要

In-situ EXAFS combined with a Paris-Edinburgh press (PEP) is an outstanding tool to investigate the local environment of trace elements in melts at high pressure and temperature. A novel design of the pressure assembly ensures a highly stable experimental setup (reaching temperatures of up to 2000 K at 2.5 GPa) while permitting the necessary level of X-ray transmission. This study focuses on the structural incorporation of the geochemically important trace elements Y and Sr in sodium-rich silicate-carbonate melts. Y and Sr K edge EXAFS were collected in transmission mode of the melt (at ～2.5 GPa, 1600 K) and its respective quench products. Distinct changes in the XANES region suggest a change in site symmetry during the cooling process.