Sedimentary rock formation occurs through a process called lithification, where sediments are compacted and cemented over time. These sediments can include particles from rocks, minerals, and organic materials that accumulate in layers, often in bodies of water like rivers, lakes, and oceans. As layers build up, the weight of the overlying material compresses the lower layers, causing them to harden. This process can take thousands to millions of years, resulting in various types of sedimentary rocks, such as sandstone, shale, and limestone, each with unique characteristics based on their composition and formation environment.