PARTICLE GEOMETRY CHANGE BY ABRASION AND FRAGMENTATION: ANALYSIS OF THE PHENOTYPIC TRAITS

People of a race may look different but share a ‘phenotypic trait’ due to a common genetic origin, e.g., a common appearance of Indian women. Mineral particles are like humans: they appear different despite having a same geological origin. Then, do the particles have some sort of ‘phenotypic trait’ in the geometries as we do? The human body shape also changes as a child grows, meaning there is a change in the phenotypic trait. Likewise, the shape of mineral particle changes with its size. For example, when mineral particles are weathered by water and/or wind, the shape of the particles change to more rounded shape or broken into smaller pieces with sharp edges due to fracture. Then, how do the mineral particles exhibit a change in the ‘phenotypic trait’? This presentation discusses the ‘phenotypic trait’ of mineral particles and demonstrates how we can systematically quantify the particle geometry changes due to abrasion and fracture based on the concept of the phenotypic trait. The key idea is using the power-law relation between surface-area-to-volume ratio (A/V) and the volume (V). The power regression reveals the geometric ‘variation’ and ‘average’ which are the important ‘phenotypic traits’ of mineral particles. The A/V ratio is also called the ‘specific surface area per unit volume’, which is considered an important particle-scale property that governs the physical phenomena of mineral solids. Therefore, we can leverage this information to better estimate the changes in the strength, permeability, and transport processes of particles. This presentation will highlight the major findings of the research.