Large strain shearing of halite: Experimental and theoretical evidence for dynamic texture changes

We report results from torsion experiments on polycrystalline halite (NaCl) to shear strains γ=8 and observe a very complex texture evolution. The same behavior was reproduced with polycrystal plasticity simulations, suggesting that we capture the underlying mechanisms. While crystal shapes gradually rotate into the shear plane, crystal orientations change continuously and dynamic texture patterns evolve with increasing shear. This is highly significant for ultra-large deformation, as for example implied from geodynamic modeling for the deep earth, where seismic anisotropy patterns may develop and locally disappear again as material is deformed during convection. The study also suggests that caution is required when interpreting deformation mechanisms from simple shear preferred orientation patterns.