Ghiorso and Evans (2008) Fe-Ti oxide geothermobarometer

Calculations specified on this page are performed using the model of:

Ghiorso MS , Evans BW (2008) Thermodynamics of Rhombohedral Oxide Solid Solutions and a Revision of the Fe-Ti Two-oxide Geothermometer and Oxygen-barometer American Journal of Science 308, 957-1039.

A standalone Macintosh program for OS 10.5 (Leopard) and OS10.6 (Snow Leopard) may be downloaded from the OFM Software repository.

Enter compositions into the form below or download the Microsoft™ Excel spreadsheet described at the bottom of the page.

Note: If the error message "Could not connect to host" is returned when attempting to use the calculator, or if the Excel spreadsheet does not execute the calculations properly, it is likely that the server performing these calculations here at OFM Research is in an unresponsive state. If you encounter this error please email the webmaster, who will reboot the server to restore functionality.

Input compositions of coexisting oxides:

Magnetite wt %


wt %
SiO2 SiO2
TiO2 TiO2
Al2O3 Al2O3
Fe2O3 Fe2O3
V2O3 V2O3
Cr2O3 Cr2O3

Documentation on web services that support this page.

Microsoft™ Excel Workbook

If you have access to either Microsoft™ Excel for Windows XP (Excel 2002) or Excel 2003, running under Windows 98, ME, NT, XP, 2000, or Windows Server 2003, you may choose to download an Excel workbook that provides a Visual Basic function which calculates temperatures and oxygen fugacities from tabulated oxide compositions. The workbook requires installation of the following optional Excel components:

depending on the version of Excel or Office that is installed. Instructions and a usage example are included in the workbook. Execution of workbook functions requires an active internet connection, as the built in VBA macros perform their calculations by contacting web services at Firewall or Windows security settings may interfere with the performance of workbook functions.