Recent Advancements in X-Ray and Neutron Imaging of Dynamic Processes in Earth SciencesSubmit Manuscript on this topic
Dynamic processes in earth sciences can be studied by multiple methods. In particular, imaging techniques play an important role in several research fields of geosciences. Optical and scanning electron microscopy techniques are widely adopted 2D imaging techniques for the investigation of the texture and morphology in a large range of materials. The conventional approach to investigate the behavior of geomaterials at non-ambient conditions, such as high temperature, high pressure, etc. is based on the study of post-mortem samples, in a “cook-and-look” fashion. In the past, due to analytical limitations, our understanding of these processes was almost exclusively based upon ex-situ analyses of the final products rather than analyses of the systems during such processes. Textural analyses usually have to be performed on thin sections of the sample after the dynamic experiment is finished (or interrupted) in order to quantify kinetic and dynamic processes. Several indirect analytical techniques can be used to quantify microstructural properties of natural and experimental samples such as pycnometry that provide estimates of porous media permeability or electron backscatter diffraction providing insights about nucleation and growth mechanism involved in the crystallization process. Although these methodologies have led to many important insights and improvements in understanding also the dynamics of geological materials, these approaches can provide at most only an incomplete view of spatially and temporally variable systems or are destructive in nature. Many phenomena remain unclear because it was impossible to observe and record the formation processes continuously, or because of the lack of an effective way of quenching the sample.
Many processes involved in the evolution of volcanic, metamorphic, and reservoir rocks, cement-based materials and ceramics are inherently dynamic and require an investigation in 4D (three-dimensions, 3D, + time) to be fully understood. These processes include mechanical properties characterization, reactive transport, heating, freezing.
The high-penetrating power of hard X-rays and neutrons, the recent advances in instrumentation and computational methods fostered the growth of novel imaging approaches, making microradiography and computed microtomography unique tools to observe internal structures of materials undergoing processes such as melting, vesiculation, growth, dissolution or reaction of crystalline phases, fluid flow. Two- and three-dimensional imaging experiments carried out under controlled external conditions represent the next generation of in-situ time-resolved experimental observations.
In this Research Topic we will focus on 2D and 3D hard X-ray and neutron-based imaging techniques. In most cases, these studies require a multidisciplinary and integrated approach based on the combined use of morphological, textural and chemical analytical techniques.
The intention of this Research Topic is to publish outputs corresponding to the current state of the art in this field, focused on the above-described areas of application. We encourage researchers in these rapidly growing areas to consider contributing to our Research Topic.