• journal_title：American Mineralogist
• Contributor：Hiroshi Kojitani ; Madoka Oohata ; Toru Inoue ; Masaki Akaogi
• Publisher：Mineralogical Society of America
• Date：2012-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2012.4054
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：97
• issue：8-9
• firstpage：1314
• section：Articles

Isobaric heat capacities (C_P) of Mg₂SiO₄ forsterite and ringwoodite were measured by differential scanning calorimetry in the temperature range of 306–833 K. The measured C_P of Mg₂SiO₄ forsterite was consistent with those reported by previous studies. On the other hand, the present C_P of Mg₂SiO₄ ringwoodite was about 3–5% larger than those measured by previous researchers. The calorimetric data of Mg₂SiO₄ ringwoodite were extrapolated to 2500 K using a lattice vibrational model calculation, which well reproduced the low-temperature C_P data measured by thermal relaxation method. The calculated C_P shows good agreement with the present calorimetric data. The obtained C_P was expressed by the polynomial of temperature: C_P = 164.30 + 1.0216 × 10⁻²T + 7.6665 × 10³T⁻¹ – 1.1595 × 10⁷T⁻² + 1.3807 × 10⁹T⁻³ [J/(mol·K)] in the range of 250–2500 K.