Sedimentary rocks are made up of all sorts, it depends on what settles at the bottom. The different rocks/particles (sediment) settle and get squashed until they’re really compact. The water is eventually squeezed out of it and rock and crystals of salts in the sediment begin to form. These crystals act as a glue and cement the rocks/particles together, forming sedimentary rock. This whole process takes millions of years to form and 75% of the earth’s surface is sedimentary rock.
Some examples of materials used to make sedimentary rock include pebbles, sand, silt, calcium sulphate, salt, calcium carbonate, remains of ancient plants and animals and silica, to name but a few!
Yes, sedimentary rock is a great place to look for fossils. Sometimes you can see the plants or animals that became part of the sediment preserved forever for us to find.
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