The Textures of Rocks in the Earth’s Deep Interior: Part I. Understanding Anisotropy and Textures in Earth Materials

Abstract

Physical properties of rocks are determined by texture, ie, the preferred orientation of crystallites. Findings on material sciences have been applied to Earth materials, particularly when dealing with seismic anisotropy from deep Earth. In this contribution we review different techniques to describe texture in rocks quantitatively. Diffraction techniques are widely used, including EBSD, synchrotron and neutron diffraction. EBSD provides complimentary information about local texture and microstructure, while neutron and X-ray diffraction are bulk texture measurements. In situ studies of high-pressure and high-temperature texture are evolving due to the combination of Diamond Anvil cells (DIA) and synchrotron sources, posing new questions on Earth’s deep dynamic. Along with techniques, methods of data analysis are critical, as most rocks are composed by low symmetry phases. Finally, the application of polycrystal plasticity simulations to understand texture in rocks is limited, but it provides a simplified framework to evaluate the impact on texture of deformation and other phenomena like recrystallization.