Negative pressure-temperature slopes for reactions forming MgSiO 3 perovskite from calorimetry

E. Ito, M. Akaogi, L. Topor, A. Navrotsky

Research output: Contribution to journalArticlepeer-review

145 Scopus citations

Abstract

A new and sensitive differential drop solution calorimetric technique was developed for very small samples. A single experiment using one 5.18-milligram sample of perovskite, synthesized at 25 gigapascals and 1873 Kelvin, gave 110.1±4.1 kilojoules per mole for the enthalpy of the ilmenite-perovskite transition in MgSiO3. The thermodynamics of the reaction of MgSiO3 (ilmenite) to MgSiO3 (perovskite) and of Mg 2SiO4 (spinel) to MgSiO3 (perovskite) and MgO (periclase) were assessed. Despite uncertainties in heat capacity and molar volume at high pressure and temperature, both reactions clearly have negative pressure-temperature slopes, -0.005±0.002 and -0.004±0.002 gigapascals per Kelvin, respectively. The latter may be insufficiently negative to preclude whole-mantle convection.

Original languageEnglish (US)
Pages (from-to)1275-1278
Number of pages4
JournalScience
Volume249
Issue number4974
DOIs
StatePublished - 1990
Externally publishedYes

ASJC Scopus subject areas

  • General

Fingerprint

Dive into the research topics of 'Negative pressure-temperature slopes for reactions forming MgSiO <sub>3</sub> perovskite from calorimetry'. Together they form a unique fingerprint.

Cite this