GALE Applied to Study Metamorphic Core Complexes

Le Pourhiet, et al.’s (2012) recent paper on the Kinematic Interpretation of the 3D Shapes of Metamorphic Core Complexes compared 3D numerical experiments performed with GALE, a CIG maintained code, to finite strain observed in the field within the ductile crust, which is exhumed within dome shaped structures called metamorphic core complexes. Their study focuses on the impact of 3D kinematic extensional boundary conditions on the 3D shape of these domes. They show for the first time, that domes formed in transtensional step over; or at the tip of propagating strike-slip faults, display a finite strain field which can be interpreted as characteristic of a transpressive domes, although on their model no shortening was applied in the far field. Their study used Q1Q1 elements and each run consisting of 200-300 time steps, required 72 hr of computation using a parallel geometric multigrid solver on 16 CPUs. A full description of the multigrid method used in GALE is provided in Appendix B of their paper. Supplementary materials are also included so readers may reproduce the results and, post-process the finite strain field and export it to VTK format out of any GALE model. [Le Pourhiet, L., B. Huet, D. A. May, L. Labrousse, and L. Jolivet (2012), Kinematic interpretation of the 3D shapes of metamorphic core complexes, Geochem. Geophys. Geosyst., 13, Q09002, doi:10.1029/2012GC004271.]