3D PARTICLE-SIZE DISTRIBUTIONS FROM 2D OBSERVATIONS - STEREOLOGY FOR NATURAL APPLICATIONS

We have developed a general formulation for stereological analysis of particle distributions which is applicable to any particle size or siz e distribution (not limited to log-normal, unimodal, etc.). We have ap plied numerical techniques to define intersection probability distribu tions for any shapes (previously only known for spheres), and quantifi ed the errors involved in using spherical coefficients for various non -spherical particles. This stereological technique is based on knowing the probability distribution of random cross-sections through various particles so that 'small circle' cross-sections can be subtracted fro m an observed population to provide the 3D size distribution of partic les. The results indicate that the most important parameter controllin g calculated size distribution is particle aspect ratio. For a distrib ution of particles with a specific aspect ratio or range of aspect rat ios, variations of particle form (spherical vs. cubic; rectangular vs. elliptical) do not alter the results, so the technique can be applied to a range of particle shapes. Applications can be made in a petrolog y, volcanology, and other fields, only a few of which can also be trea ted using expensive X-ray techniques. (C) 1998 Elsevier Science B.V. A ll rights reserved.