Ontario Grade 9 Geography Practice Exam

The formation of sedimentary rocks occurs through the processes of compaction and cementation of sediments. Sediments, which consist of particles from pre-existing rocks, minerals, or organic materials, accumulate in various environments, such as riverbeds, lakes, and ocean floors. Over time, layers of sediment build up, and the weight of the overlying material exerts pressure on deeper layers, resulting in compaction.

During compaction, the spaces between sediment particles decrease, and this compression helps in the consolidation of sediments. Following compaction, cementation occurs when minerals dissolved in water precipitate out and fill the gaps between the sediment particles, effectively ‘gluing’ them together. This process transforms loose sediment into solid rock, leading to the creation of sedimentary rock formations.

Understanding this process is vital for recognizing how different types of rocks are formed and classified within the rock cycle.