The bridgmanite–akimotoite–majorite (Bm–Ak–Mj or BAM) triple point in MgSiO3 has been measured in large-volume press (LVP; COMPRES 8/3 assembly) and laser-heated diamond anvil cell (LHDAC). For the LVP data, we calculated pressures from the calibration provided for the assembly. For the LHDAC data, we conducted in situ determination of pressure at high temperature using the Pt scale at synchrotron. The measured temperatures of the triple point are in good agreement between LVP and LHDAC at 1990–2000 K. However, the pressure for the triple point determined from the LVP is 3.9 ± 0.6 GPa lower than that from the LHDAC dataset. The BAM triple point determined through these experiments will provide an important reference point in the pressure–temperature space for future high-pressure experiments and will allow mineral physicists to compare the pressure–temperature conditions measured in these two different experimental methods.

Britany L. Kulka, Jonathan D. Dolinschi, Kurt D. Leinenweber, Vitali B. Prakapenka, Sang-Heon Shim, “The Bridgmanite–Akimotoite–Majorite Triple Point Determined in Large Volume Press and Laser-Heated Diamond Anvil Cell,” Minerals-Basel 10 (1), 67-1-67-12 (2020). DOI: 10.3390/min10010067 abstract

Raman spectra of the samples recovered from the Large-Volume Press (LVP) runs: The vertical lines highlight the key peaks for the identification of Bm (blue) at 383 cm−1, Ak (red) at 799 cm−1, and Mj (yellow) at 931 cm−1. An LVP run ID is provided to each spectrum.