Sedimentary Rock

Sediments are loose, unconsolidated rock particles and ions (i.e., charged atoms) dissolved in aqueous solutions. Sedimentary rocks, which constitute about 75% of all rocks exposed at the surface of the Earth, form when the particles are cemented together or when crystals precipitate from the solutions. Sedimentary rocks (particularly sandstones) are important because they host petroleum deposits and most of the uranium used for generating nuclear energy. There are three types of sedimentary rocks: (1) clastic (or detrital), (2) biochemical, and (3) chemical.

Clastic sedimentary rocks constitute more than 75% of the total sedimentary rocks. These rocks are formed from cemented grains and particles derived from the breakdown of preexisting rocks of any type (e.g., igneous, sedimentary, or metamorphic). The classification of clastic sedimentary rocks is based ...