Sedimentology studies the properties, origins, and historical interpretation of sediments and sedimentary rocks. Such materials are formed by physical, chemical, and biological processes, at temperatures ranging from below freezing to about 150-200 degrees C.More than 75% of the earth's land surface is covered by sediments and sedimentary rocks. Near-surface sediments constitute the reservoirs for almost all groundwater, and are vitally important substrates for soils, wetlands, and shallow marine environments