(n.) Geology. The unconsolidated grains of minerals, organic matter or preexisting rocks, that can be transported by water, ice or wind, and deposited. The processes by which sediment forms and is transported occur at or near the surface of the Earth and at relatively low pressures and temperatures. Sedimentaryrocks form from the accumulation and lithification of sediment. Sediments are classified according to size by the Udden-Wentworth scale. See: Alluvial, Alluvium, Arenaceous, Argillaceous, Bed, Bouma Sequence, Caliche, Channel, Clastic Sediment, Clay, Compaction, Consolidated, Cubic Packing, Delta, Depocenter, Deposit, Deposit, Depositional Energy, Depositional Environment, Depositional System, Detrital, Diagenesis, Diatomite, Differential Compaction, Dipping Bed, Eolian, Feldspar, Hiatus, Lacustrine, Marine, Mineral, Paludal, Point Bar, Reef, Salt Dome, Sedimentation, Sorting, Subsidence, Terrestrial, Turbidity Current, Udden-Wentworth Scale, Varve