sedimentologie

Sedimentologie is the branch of geology that studies natural sediments and the processes that form, transport, deposit, and transform them. It focuses on clastic, chemical, and organic sediments and on the facies they record in outcrops, cores, and modern environments.

Key processes include weathering and erosion producing sediment, transport by water, wind, ice, or gravity, deposition when transport energy decreases, and diagenesis, including compaction and cementation, that lithifies sediments into sedimentary rocks. Sedimentology thus helps explain how the Earth's surface is shaped and how the rock record preserves information about past environments and climate. It is closely linked to stratigraphy and paleogeography.

Sedimentology examines sediment grain size, shape, sorting, composition, and fabric, as well as sedimentary structures such as bedding, cross-bedding, ripple marks, mud cracks, and trace fossils. It distinguishes depositional environments like rivers (fluvial), lakes (lacustrine), deltas, deserts (aeolian), and marine settings from shoreline to deep sea. Modern analog studies of active environments aid interpretation of ancient rocks.

Methods include field mapping, sampling, grain-size analysis, petrography, geochemistry, and sedimentary dating using relative and absolute techniques. Applications span hydrocarbon exploration and production, groundwater and aquifer assessment, environmental geology, tectonic history, and climate reconstruction through sedimentary records.