Sedimentary rocks are primarily formed from what?

Sedimentary rocks are primarily formed from the accumulation and compaction of materials that are derived from pre-existing rocks or organic materials. This includes fragments of rocks, minerals, and even the remains of plants and animals. These materials, known as sediments, can accumulate in various environments, such as riverbeds, lake bottoms, and ocean floors. Over time, these sediments become compacted under pressure and can bond together through the process of cementation, leading to the formation of sedimentary rocks.

For instance, sandstone is a type of sedimentary rock that is primarily composed of sand-sized particles, often from pre-existing rocks, while limestone can be primarily formed from shells and skeletons of marine organisms. This formation process highlights how sedimentary rocks are intrinsically linked to both the weathering and erosion of other rocks, as well as biological processes.