Sedimentary rock the sedimentary cover can become unstable, causing turbidity currents. Turbidity currents are sudden disturbances of the normally quite deep marine environment and can cause the geologically speaking instantaneous deposition of large amounts of sediment, such as sand and silt. The rock sequence formed by a turbidity current is called a turbidite. The coast is an environment dominated by wave action. At a beach, dominantly denser sediment such as sand or gravel, often mingled with shell fragments, is deposited, while the silt and clay sized material is kept in mechanical suspension. Tidal flats and shoals are places that sometimes dry because
Earthen plaster lime or gypsum, while stucco uses a cement or synthetic binding element. Clay is a soil component consisting of extremely fine particles. Most clays consist of hydrous aluminum silicates, though there is a considerable amount of chemical variation among the clays. Clay is cohesive and binds to the sand and the straw, holding the mixture together, as well as securing the mixture to the wall. Clay is also plastic when wet, which makes the plaster mixture workable. Sand provides structure, strength, and bulk to earthen plasters. Sand consists of tiny mineral granules of rock, its parent material. Predominately composed of