Sediment layers are distinct layers of material that accumulate over time in various environments, such as rivers, lakes, and oceans. These layers are formed from particles like sand, silt, and clay, which settle to the bottom as water slows down. Each layer represents a specific period in history, capturing information about the environment at that time. Geologists study sediment layers to understand Earth's history and changes in climate. By examining the composition and thickness of these layers, scientists can learn about past events, such as volcanic eruptions or glacial movements, and how they have shaped the landscape over millions of years.