Lithologie

Lithology, known as lithologie in French, is the branch of geology concerned with describing rocks on the basis of their physical characteristics and mineral composition. It emphasizes identifying rock types, textures, grain size, cementation, color, and other visible or measurable properties to define lithologies and lithologic units used in geological mapping and interpretation.

In the field, geologists document rock color, hardness, grain size and shape, fabric, bedding or foliation, and weathering features. In the laboratory, petrographic microscopy reveals mineralogy and textures in thin section; instruments such as X-ray diffraction determine mineral phases; geochemical analyses (XRF, ICP-MS) and isotopic studies aid in quantifying composition and provenance.

Lithology complements broader petrologic analysis. It distinguishes lithologies within a rock sequence and supports classifications such as lithofacies in sedimentary rocks, lithostratigraphy, and rock names within the igneous, sedimentary, and metamorphic families.

Applications span petroleum geology, hydrogeology, civil engineering and environmental geology, mining, and planetary science, where lithology describes the surface and near-surface rocks. While lithology focuses on description and classification, it is closely integrated with petrology, sedimentology, geochemistry, and structural geology to interpret rock history.