I have been doing some numerical modeling to explore interactions between buoyantly driven mantle plumes and accretionary boundaries! I presented a poster at AGU in December, 2010 on my findings between April 2010 and December 2010 but I have gone so much further since then.
Most of my traffic is from people without much science in their lives (yes that is an actual varialbe measured by Google Analytics okay?) so here I'm keeping it simple but if you have questions about anything more technical just email me!
Model Description
This cartoon shows the boundary and initial conditions of a plume-ridge interaction model in 2D. I hope this gives an easy to understand picture of how I set up a numerical model to simulate a portion of the mantle and lithosphere, but keep in mind that this figure is extremely simplified!
Three very important things are defined in the model in an attempt to simulate the properties within the Earth as we know them: temperature, rheology, and thermal buoyancy. Temperature is defined according to a half-space cooling model, which means lithosphere cools and condenses with time. Rheology is based on diffusion creep deformation, which means strain rate and stress are related linearly. Thermal buoyancy is defined as a volume force throughout the entire domain and it is the force opposing gravity that attempts to bring systems into gravitational equilibrium.
This is what some of the output from the model looks like, visualized. The black line at the top is an isotherm at about 800 K showing the general shape of the lithosphere and the position of the ridge.
On the left we can see how plume material moves throughout the mantle in response to the ridge. Two big things are going on: buoyancy drives the excessively heated plume to rise into the void left by the ridge, but lithosphere is also moving away from the ridge pushing plume material to the right.
NEXT: WE LOOK AT SOME RESULTS AND TALK ABOUT THEM FOR A MINUTE