COG3 Seminar: Ben Holtzmann (Columbia Univ.)
Friday, December 01, 2017 at 10:00am to 11:00am
Building E25, 119
45 CARLETON ST, Cambridge, MA 02142
"Inference of thermodynamic state of the upper mantle: Can we spot thermal disequilibrium between the lithosphere and asthenosphere?"
An understanding of the driving and resisting forces for plate motion (among other ridiculously large problems such as the composition and chemical evolution of the Earth) requires an understanding of the thermodynamic state of the interior: its pressure, temperature, composition, and material structure. Coming from a rock mechanics perspective, there is a need for laying out of the wide range of approaches people have taken to this problem. Here, I present a forward approach (in the form of a piece of software) that integrates elastic, viscous and anelastic constitutive models. I illustrate the method with an application to the classic surface wave-derived Vs profiles for the stable and tectonic North America (SNA, TNA) from Grand and Helmberger (1984). It appears that the SNA profile can be fit with a single steady state profile, but the TNA profile cannot, providing a quantitative estimate of the thermodynamic disequilibrium. This inference becomes more concrete when looking t more recent USArray data beneath the Colorado Plateau.
About this Seminar
The Chemical Oceanography, Geology, Geochemistry, and Geobiology Seminar [COG3] is a student-run seminar series. Topics include chemical oceanography, geology, geochemistry, and geobiology. The seminars take place on Fridays from 10-11am in Building E25, Room 119, unless otherwise noted (term-time only).