A new thermodynamic model for sapphirine: calculated phase equilibria in K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3. (10th February 2014)

• Record Type: Journal Article
• Authors: Wheller, C. J.; Powell, R.
• Is Part Of: Journal of metamorphic geology. Volume 32:Number 3(2014:Apr.)
• Page Start: 287
• Page End: 299
• Publication Date: 2014-02-10
• Subjects: Metamorphism (Geology) -- Periodicals; 552.4
• DOI: 10.1111/jmg.12067
• Languages: English
• ISSNs: 0263-4929

Abstract

<abstract abstract-type="main" id="jmg12067-abs-0001"> <title>Abstract</title> <p>The activity–composition (<italic>a</italic>–<italic>x</italic>) relations of sapphirine are re‐evaluated in the light of a recent new internally‐consistent data set of phase end‐members for use in phase equilibria modelling, particularly of ultra‐high‐temperature (UHT) rocks. This is achieved with the aid of relatively oxidized sapphirine+quartz‐bearing granulites from Wilson Lake, Canada. Calculated <italic>P</italic>–<italic>T</italic> projections and compatibility diagrams in the K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O–TiO₂–Fe₂O₃ (KFMASHTO) system are used to illustrate sapphirine+quartz‐bearing phase equilibria in the context of UHT metamorphism. These new <italic>a</italic>–<italic>x</italic> relations for sapphirine should allow pseudosection thermobarometry in NCKFMASHTO for estimating peak <italic>P</italic>–<italic>T</italic> conditions of sapphirine‐bearing rocks.</p> </abstract>