Sedimentary rocks are formed through a series of processes that involve the weathering and erosion of pre-existing rocks. Over time, these rocks are broken down into smaller fragments called sediment. This sediment is then transported by water, wind, or ice and eventually deposited in layers. As more layers of sediment build up, the weight and pressure from the overlying layers compact the sediment together. This process is known as lithification. Over millions of years, the minerals in the sediment are cemented together to form solid rock. There are three main types of sedimentary rocks: clastic, chemical, and organic. Clastic rocks are made up of fragments of pre-existing rocks, chemical rocks are formed from minerals that precipitate out of solution, and organic rocks are composed of the remains of living organisms. Sedimentary rocks are important because they provide valuable information about Earth's history. Fossils found in sedimentary rocks can indicate the past environments and climates that existed on Earth. By studying sedimentary rocks, geologists can learn more about processes that have shaped the Earth over millions of years.