This is a partially developed activity description. It is included in the collection because it contains ideas useful for teaching even though it is incomplete.
Modeling Fractures in Thermal Systems: Thermal-Mechanical Feedback and Vein Formation
Barb Dutrow, Department of Geology & Geophysics, Louisiana State University
Topic: Mineralogy, Petrology, fracture formation
Course type: Upper level undergraduate course
In many geologic systems, rocks record a series of fracture events and subsequent fracture sealing by numerous generations of minerals filling a vein. These fracture episodes can be driven by thermal expansion of pore fluids. As thermal energy dissipates from a cooling magma, heat is transferred to the surrounding host rocks and their contained fluids. This exercise would couple thermal dissipation of a cooling magma with heating of the pore fluids in the host rocks and their mechanical properties to model fracturing episodes. A thermal-mechanical feedback is proposed.
Learning Goals or Outcomes
Understanding the thermal-mechanical-chemical feedback effects in fluid-rock systems and the processes controlling the fracturing. Students could then relate these processes to real rocks with multiple generations of veins.
How would you assess whether those goals have been met?
Students would run the model, change input parameters, evaluate the system's response and ultimately relate these features to real rocks. A term paper and/or presentation would summarize these outcomes.
A preliminary modeling approach (C + Fortran) was used by
Dutrow and Norton, 1995, J. Metamorphic Geology, Evolution of fluid pressure and fracture propagation during contact metamorphism. v. 13, p 677-686. I would like to develop this using a student friendly and more sophisticated approach.