Chlorine in wadsleyite and ringwoodite: An experimental study

We report concentrations of Chlorine (Cl) in synthetic wadsleyite (Wd) and ringwoodite (Rw) in the system NaCl–(Mg, Fe)2SiO4 under hydrous and anhydrous conditions. Multi-anvil press experiments were performed under pressures (14–22 GPa) and temperatures (1100–1400 °C) relevant to the transition zone (TZ: 410–670 km depth). Cl and H contents were measured using Particle Induced X-ray Emission (PIXE) and Elastic Recoil Detection Analysis (ERDA) respectively. Results show that Cl content in Rw and Wd is significantly higher than in other nominally anhydrous minerals from the upper mantle (olivine, pyroxene, garnet), with up to 490 ppm Cl in anhydrous Rw, and from 174 to 200 ppm Cl in hydrous Wd and up to 113 ppm Cl in hydrous Rw.