从流变学到相关的几何学的剪切区模拟
The geometry of ductile strain localization phenomena is related to the rheology of the deformed rocks. Both qualitative and quantitativerheological properties of natural rocks have been estimated from finite field structures such as folds and shear zones. We apply physical modellingto investigate the relationship between rheology and the temporal evolution of the width and transversal strain distribution in shear zones,both of which have been used previously as rheological proxies. Geologically relevant materials with well-characterized rheological properties(Newtonian, strain hardening, strain softening, MohreCoulomb) are deformed in a shear box and observed with Particle Imaging Velocimetry(PIV). It is shown that the width and strain distribution histories in model shear zones display characteristic finite responses related to materialproperties as predicted by previous studies. Application of the results to natural shear zones in the field is discussed. An investigation of theimpact of 3D boundary conditions in the experiments demonstrates that quantitative methods for estimating rheology from finite natural structuresmust take these into account carefully.