How does sedimentary rock typically form?

Sedimentary rock typically forms through the process of compaction and cementation of sediments. These sediments can originate from the erosion of pre-existing rocks, organic material, or chemical precipitation. Over time, layers of these sediments accumulate, often in bodies of water like rivers, lakes, and oceans. As more layers build up, the weight of the overlying material exerts pressure on the deeper layers, causing them to compact and eventually lithify into sedimentary rock.

This process distinguishes sedimentary rock formation from other rock types. For example, igneous rocks form from the cooling and solidification of magma, either beneath the Earth’s surface or after it erupts as lava. Metamorphic rocks, on the other hand, form from existing rocks undergoing alteration due to high heat and pressure, not from sediment accumulation. Understanding the processes that lead to the formation of sedimentary rocks is essential in geosciences, as these rocks often contain fossils and are significant for interpreting Earth's history and past environments.