How do Sediments Become Sedimentary Rocks?
To become a sedimentary rock, sediments must be lithified, or cemented into stone. As sediments pile atop other sediments, the earliest deposits become deeply buried. Weight of overlying sediment places pressure on those below. Sediment under pressure compacts. The tighter the sediment is squeezed, the less room there is for water or air between grains and grains to stick together. Something else has to happen to turn these sediments into rock. Cementation is the word given to the sticking together of sediments by additional material between grains. Water flowing between grains contain silica, carbonate or other dissolved materials that precipitate out of solution and attach to grain surfaces. Eventually, enough mineral precipitates out that it cements grains into a whole. Sedimentary Rocks are Clues to Past Environments Sedimentary rocks can tell a geologist much about past environments. These rocks are keys to reading Earth’s past. Connecting to the following activity will further de
