Research themes
My colleagues and I measure the strength of earth and icy planetary materials at high pressures and extreme temperatures (hot or cold). The work is mostly experimental and mostly done indoors. The overriding purpose of our experiments is to provide constraint for dynamic models--from deep interiors to near surface--anywhere that strength of materials comes into play. We currently concentrate in two areas:
Flow and fracture of water ice (including its high-pressure phases through ice VI), and of other frozen volatiles (such as methane, ammonia, carbon dioxide) to help constrain models of planetary dynamics and surface geology on Mars and icy satellites of the outer solar system.
(Click on the images for an enlarged view)
Flow of mantle rocks (especially olivine) to help us constrain the internal dynamics of our own planet. These experiments involve a new kind of deformation apparatus called the Deformation-DIA and the use of synchrotron x rays to measure stress and plastic strain.
Current research programs
"Experimental Investigations of the Rheologies of Planetary Ices," 2006-2009, NASA [See
proposal summary]
"Laboratory Measurements of the Rheological Effects of Dust Upon Water Ice," 2005-2008,
NASA [See proposal summary]
"Rheology of Earth's Interior," 2007-2009, Office of Science, Basic Energy Sciences,
DOE [See proposal summary]
"CSEDI Collaborative Research: Grand Challenge for Experimental Study of Plastic Deformation
Under Deep Earth Conditions," 2007-2010, NSF [See proposal
summary]
Some recent projects (Click on the images)
Our new plans to study grain size-sensitive vs. grain size-insensitive flow in ice I
Gas clathrate hydrates may appear "ice-like," but we have discovered that they are rock-hard.
Is the Mars south polar cap made of CO2? Lab experiments come through again.
New views of materials bring new questions. We we are starting to use numerical modeling to solve fresh problems in strength of materials.
Grain-size sensitive creep of high-pressure ice II
Measuring rates of dissolution of methane and CO2 clathrate hydrates in a seafloor laboratory
Not everything works the first time. Check out our attempt to measure the creep strength of solid nitrogen and other so-called "vander Waals solids."
