LamelODF: a MATLAB-based toolbox for orientation distribution analysis and mapping of lamellar minerals for laboratory and synchrotron X-ray diffractometers.

Abstract

We present LamelODF, a MATLAB-based software platform for automated extraction and mapping of axisymmetric orientation distribution functions (ODFs) from 2D X-ray diffraction patterns of lamellar minerals. Building on a maximum-entropy-method-derived ODF specifically for clay mineral systems, the software provides a streamlined workflow for texture analysis under the assumption of transverse isotropy. The program features dedicated file converters for both laboratory and synchrotron data formats, batch processing capabilities, and flexible background-correction algorithms. The analytical pipeline performs azimuthal intensity integration with background subtraction, followed by non-linear fitting to extract quantitative orientation parameters including the 〈P ₂〉 order parameter, the deviation angle δ between the main orientation of lamellar particles and the detector reference, and integrated intensities, focusing specifically on basal 001 reflections to enable rapid processing of thousands of diffraction patterns for spatial mapping applications. Mapping of a laboratory-prepared porous clay medium and a natural soil sample demonstrates the software's ability to detect density stratification, sedimentation discontinuities and complex geological structures such as relict topsoil crusts. The software successfully discriminates between different clay mineral phases, providing a practical complementary tool for researchers investigating the organization of lamellar minerals in natural and engineered materials.