Sedimentation and Sedimentary Rocks

Sedimentary rocks are one component of the modern threefold classification of rocks. They derive from the lithification of sediments, which are produced in basically two ways: by the mechanical deposition of grains derived from the alteration of other rocks (detrital or clastic rocks), or as chemical precipitates or grains formed organically or inorganically from an aqueous solution. The whole process of sedimentation is generally considered to comprise weathering of the parent rock, the transport of grains or ions in solution, and deposition or precipitation. The origin of sediments is thus an exogenic process, and is strongly influenced by climate, and in most cases also by biological processes. Sediment deposition normally happens in local depressions called “sedimentary basins,” the most significant being the marine basins. Lithification takes place during burial through a series of transformations called “diagenesis.”