Tony Withers

Assistant Professor, Department of Earth Sciences.

My research

I am an experimental petrologist. I'm particularly interested in the origin, incorporation, storage and processing of volatile elements in terrestrial planets. My students are investigating the use of non-traditional stable isotopes as tracers of mantle processes, the stability of nitrogen-bearing phases at upper and lower mantle pressures, the hydrogen content of nominally anhydrous minerals in sub-continental lithosphere and in extraterrestrial objects, and the effects of composition and temperature on the structure of silicate glass.

In my lab we use end-loaded piston cylinders for experiments at pressures up to 3.5 GPa. We also have facilities for preparing experimental samples for infrared and secondary ion mass spectroscopy, and high temperature furnaces for glass making and for controlled-atmosphere experiments.

At Western we have a range of high-pressure experimental facilities that span the entire pressure range of the Earth's interior, from crust to core. Crustal pressure experiments are done in Dr Bob Linnen's cold-seal lab, Dr Rick Secco's lab houses the largest capacity multi-anvil press in North America, together with tetrahedral and Walker-style multi-anvil devices, and Dr Sean Shieh has a laser-heated diamond cell facility for experiments at even greater pressure.

Publication list

For an up to date list of my publications, use one of the following services:

If the button doesn't work, here's the link to my ResearcherID; the Google Scholar version is usually more up to date.


I teach undergraduate courses in metamorphic petrology and the origin and geology of the solar system. I also occasionally teach thermodynamics and phase diagrams in igneous petrology, and sometimes give guest lectures in mineralogy. I run a short course in planetary science for graduate students, and a seminar series for graduate students in the collaborative Earth and planetary science program at Western.

A few of my teaching tools can be found here.

Other things I do

I maintain code used for data acquisition, for data reduction and analysis of spectroscopic data, and to perform other useful tasks.

Most of my code for Igor Pro is hosted at (user name: tony). In addition, a couple of online tools are linked below.

By popular demand, I've brought the water fugacity calculator here from its former home. Here's a very compact python version for your fugacity-calculating pleasure.

And here's the molar weight calculator.

Last revised: 2017