Litologier

Litologier refer to the study and description of rocks based on their physical characteristics. The field emphasizes mineral content, grain size and arrangement, texture, color, layering, and cementation, to classify rocks and interpret their origin and history. In practice, litologier provide the basis for lithostratigraphic mapping and for distinguishing rock units in field notes, sections, and boreholes.

Rocks are categorized into three broad families: igneous, sedimentary, and metamorphic, each with characteristic lithologies. In sedimentary rocks, lithology often focuses on lithofacies, describing rock type and depositional environment (for example, sandstone lithologies indicating fluvial vs. aeolian settings). In metamorphic and igneous rocks, lithology relates to mineral assemblages and texture, which reflect the conditions of formation and subsequent alteration.

Methodology includes field description, core logging, and petrographic analysis. In the lab, thin-section petrography, X-ray diffraction (XRD), and X-ray fluorescence (XRF) yield mineralogical and chemical composition. Geophysical borehole logs and remote sensing can extend lithological information to subsurface scales, supporting continuous stratigraphic interpretation.

Litologier informs resource exploration, groundwater assessment, civil engineering, and environmental geology by characterizing rock quality, permeability, and stability. It also supports interpretations of past climates, tectonics, and sedimentary processes, and is distinct from petrology, which emphasizes origin and formation mechanisms rather than descriptive classification of rock units.