The Akimotoite--Majorite--Bridgmanite Triple Point Determined in Large Volume Press and Laser-Heated Diamond Anvil Cell

Abstract

The akimotoite--majorite--bridgmanite (Ak--Mj--Bm) 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 by Leinenweber (2012).
 For the LHDAC data, we conducted \textit{in situ} determination of pressure at high temperature using the Pt scale by Dorogokupets and Dewaele (2007) 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 triple point determined through these experiments will provide an important reference point in the pressure-temperature space for future high-pressure experiments and allow mineral physicists to compare the pressure--temperature conditions measured in these two different experimental methods.