A menu-driven Macintosh program for simulating shear-sense indicator development
- Miami Univ., Oxford, OH (United States). Geology Dept.
The authors have developed a Macintosh application program that can simulate the evolution of common shear-sense indicators including porphyroclast systems, porphyroblast inclusion patterns, and S-C fabrics. The program illustrates the underlying kinematic consanguinity of these microstructures and has many potential uses in both teaching and research. The simulation is based on the analytical solution for low-Reynolds-number shearing flow around a rigid sphere. Porphyroclast systems are modeled by continuously recrystallized mantle. Conversely, porphyroblast inclusion trails are generated by continuously increasing the object radius. S-C fabrics can be simulated by introducing active layering into the matrix. Dialog boxes allow users to specify values of input parameters including: porphyroclast recrystallization rate, porphyroblast nucleation rate, bulk shear strain rate, object size, layer spacing, degree of object-matrix coupling, and number and size of time steps. Values of these parameters may be changed during the simulation. Using the program, it has been possible to define kinematic phase diagrams'' for different types of shear sense indicators. The program has also been used to explore the controversy about porphyroblast rotation (or lack thereof) in non-coaxial deformation. Significantly, even when a simulated porphyroblast is pinned'' by relaxing the no-slip condition at the object-matrix boundary, inclusion trails are not strictly straight because layering has been deflected around the growing porphyroblast.
- OSTI ID:
- 5721374
- Report Number(s):
- CONF-921058--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 24:7; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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