Sedimentary Rocks

I will do a quick review of sedimentary rocks. Bits of rock and earth, or sediment, are constantly being eroded on the earth's surface by things like wind, waves and ice. These pieces of gravel, pebbles and the like begin to pile up in places. Over many years, these piles of rock can lithify, or turn in to solid rock, by being compacted against each other. Sedimentary rocks are all over the world, and are very rich in fossils. Limestone, sandstone and shale are some of the most common forms of this type of rock. Limestone is one of the most common materials on earth, and along with being what caves are made of, it is a very common building material, and is the base of many of the Michigan Avenue buildings we explored. Sandstones, when eroded in to small pieces, are what make up the sand on our beaches, and are generally formed by the mineral quartz, while limestone is made of calcite (the shells of dead animals). Sedimentary rocks have a great deal of color variety, can usually be found to have pores, and can contain a great many fossils. Some types of sedimentary rock may also react with acid, such as limestone.