Paul J. Tackley, Professor

News

New collaborative (with the University of Geneva) project Long-term evolution of the Earth from the base of the mantle to the top of the atmosphere: Understanding the mechanisms leading to ‘greenhouse’ and ‘icehouse’ regimes funded by Sinergia programme of the Swiss National Science Foundation! There are 5 new PhD positions available! The project is a collaboration with 3 groups at the University of Geneva. See here.

Courses taught

Planetary Physics and Chemistry

Topics in Planetary Sciences moodle site

Integrierte Erdsysteme I moodle site

Geophysik II moodle site

Geophysik III moodle site

Numerical Methods I & II (now taught by Taras Gerya)

Research

Click here for publication list with downloadable papers

Click here for my google scholar citations page

Click here for a movie showing group activities

I am interested in the thermo-chemical structure, dynamics and evolution of the interiors of solid planets and moons, including Earth, Venus, Mars, Mercury, Io and extrasolar super-Earths, focussing particularly on convection in the solid mantle and the associated dynamics of the lithosphere, which on Earth means plate tectonics. My main research tool is numerical simulation, using state-of-the-art numerical methods on high performance (massively-parallel) supercomputers to obtain more realistic, three-dimensional numerical models of dynamical processes than previously possible. Specific recent projects include:

1. Developing integrated, self-consistent models of plate tectonics and mantle convection- a long-standing problem in geodynamics. Temperature-dependent viscosity by itself leads to a rigid, immobile lithosphere ('single-plate planet')- additional rheological complexities are necessary to allow plates to form. I have developed some of the first 3-D models in which plates form in such a manner.
2. Thermo-chemical convection, including the possibility of deep chemical layering, and the thermo-chemical evolution of Earth and other terrestrial planets. The melting associated with plate tectonics causes mantle differentiation, whereas convection causes mantle mixing, and the complex interaction between these two opposing processes is what determines the planet's evolution.
3. Asthenospheric dynamics and the Yellowstone hotspot. Partial melting in the asthenosphere results in buoyancy sources that can drive flow and cause further melting. This could be an explanation explanation to deep mantle plumes for certain hotspots and other volcanism on Earth. Even if the heat source is a deep plume, these compositional effects will strongly modulate what happens in the melting region.
4. Plume dynamics and plume-lithosphere interaction. Previous mantle plume models usually assume rather small viscosity contrasts and linear rheology, and are often 2-D (axisymmetric). When you allow more realistic rheology and three-dimensionality, things can be quite different, as we have been discovering!
5. Continental collisional dynamics. A planned effort is to model the India:Asia collision.

A good general description of my research (though out of date) can be found here.

1998 article about my research in SDSC's Envision newsletter: link
1994 article in Caltech's CACR annual report: link
1994 article from Physics World (text only) "Journey to the Mantle of the Earth": link

Useful computing things

2D convection code written in Matlab (variable viscosity, staggered grid)

StagPy python software for analysing StagYY output.

StagLab and other useful software by Dr. Fabio Crameri.

Matlab scripts that read StagYY output files and write as VTK (by Boris Kaus).

Instructions for making a movie from a series of consecutively numbered images

How to compile OpenDX and loadable modules for it on MacOS 10.6 Snow Leopard

Parallel Computing

Other Things

Group members and friends at the 2007 Goldschmidt conference in Cologne

Wave Propagation Movies

Some Convection Movies

here for 'field work' pictures at the Great Wall of China!