mesotexture

Mesotexture is a term used in geology, materials science, and related fields to describe textural features of a material that are visible at an intermediate length scale, between microtexture (features on the micrometer scale) and macrotexture (visible to the naked eye). The mesoscopic scale typically spans roughly from about 0.1 millimeter to a few millimeters, though exact boundaries vary by discipline. Mesotexture captures patterns and fabrics that are not resolved in ordinary petrographic micrographs but are larger than individual grains, such as oriented grain fabrics, intergrowths, graded laminations, and networks of porosity or mineral boundaries.

In rocks and sediments, mesotexture provides information about deformation history, deposition processes, and diagenetic alteration. Examples include foliation or lineation produced by mineral alignment under stress, preferred orientation of elongated minerals, intergrowths between mineral phases, and layering that is visible only at higher magnification or in thin sections.

Measurement and analysis of mesotexture rely on a combination of techniques. Petrographic microscopy of polished sections reveals intermediate fabrics; image analysis and fabric tensors quantify grain orientation and alignment. Scanning electron microscopy can resolve intergrowths and interfacial textures at the mesoscale, while X-ray microcomputed tomography enables three-dimensional visualization of porosity and connectivity at comparable sizes.

Significance of mesotexture lies in its influence on mechanical properties, anisotropy, permeability, and weathering behavior. It also aids interpretation of geological history and the performance of polycrystalline materials in engineering contexts. See also microtexture, macrotexture, fabric analysis, and petrography.