Neutron Scattering in Geosciences

Nikitin A. N., Ivankina T. I.

The principle advantages of neutron diffraction based on phenomenal properties of a neutron which permit to extend a range of solid-state physics problem are analyzed in the review in detail. The fundamentals of neutron diffraction texture analysis of polycrystalline materials and rocks in particular are presented. The term of crystallographic texture is defined indenting the lattice preferred orientation of rock-forming minerals as a main factor which controls the anisotropy of rocks and as an inherited property gained during plastic flow of rocks or during magmatic, metamorphic and other processes which determine the formation of lithosphere of the Earth. The basic part of the review contains new results of study of texture regularities of rocks and physical property peculiarities caused by them, for example, the behavior of elastic wave velocity at high hydrostatic pressures, the investigation of piezoelectric properties of rocks as well as magnetic and thermal properties. Applications of neutron diffraction data in complex with different physical and petrophysical methods to fundamental problems of geology and geophysics are demonstrated, such as the reconstruction of paleotectonic strains and stresses within the lithosphere block and the study of metamorphic, geodynamic and evolution processes on the basis of data on textures of deep samples (xenoliths, amphibolites and gneisses from the superdeep borehole). Neutron diffraction data of residual and intracrystalline stresses on different rocks at normal conditions and under mechanical loading are shown. Results of study of anonymous rock properties appeared at high temperatures and high pressures and their possible applications to physics of failure and to development of model of earthquake source are discussed. The state of experimental base and modern tendencies of development of rock material investigations using neutron diffraction for solving of actual fundamental and applied problems in geosciences are appreciated.