Investigation of residual strain in quartzite using neutron diffraction: Interpretation and self-consistent modelling

The residual strain determination by neutron diffraction has been performed on a set of five natural quartzite samples collected from Betic Cordilleras (Spain) and Sivas Basin (Turkey). The starting idea was to document an earlier conclusion about the texture components related either to deformation or recrystallization phenomena. Thereafter, as a consequence of the rock inhomogeneity, the complete strain tensor has been determined for each sample and discussed by taking into consideration the present-day knowledge in material sciences. The imposed macroscopic deformation observed at the sample locality led us to consider the form of the residual strain tensor as possibly representative of the natural finite plastic deformation suffered at the sample scale. Based on this, those tensors have been fitted to plastic tensors and introduced in texture simulations using a visco-plastic self-consistent (VPSC) model. The results demonstrate that the complete and meaningful strain tensor determination in rocks could be used as an experimental input in numerical modelling. This new combination of experimental and numerical approaches was validated and could help to better understand some geological phenomena.