Scanning calorimetric measurement of heat capacity during incongruent melting of diopside

R. A. Lange, J. J. De Yoreo, A. Navrotsky

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Scanning calorimetric measurements (in step-scan mode) using a Setaram HT1500 calorimeter were performed on initially crystalline diopside (CaMgSi2O6) between 1403 and 1762 K and provide a direct measurement of heat capacity. Incongruent melting begins approximately 59 K below the melting point reported previously of 1665 K. Backscattered electron imaging confirms that the starting crystalline sample is a single phase at a resolution ≥1 μm. The diopside is stoichiometric to ±2% (resolution of electron microprobe analysis). The observed incongruency, which has been noted previously, is therefore intrinsic to pure CaMgSi2O6 and not related to the presence of other phases or to deviations in the Ca/Mg ratio from unity. -from Authors

Original languageEnglish (US)
Pages (from-to)904-912
Number of pages9
JournalAmerican Mineralogist
Volume76
Issue number5-6
StatePublished - 1991
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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