https://www.nps.gov/subjects/geology/sedimentary.htm
WebSedimentary rock along the White Rim Road at Canyonlands National Park, Utah. NPS photo. Introduction. Sedimentary rocks are formed from deposits of pre-existing rocks or pieces of once-living organism that accumulate on the Earth's surface. If sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock.