Final answer:
Existing rocks are broken down into sediment through mechanical and chemical weathering, with quartz showing the greatest resistance to these processes. Sediments are transported by water or air and eventually lithify into sedimentary rocks through compaction and cementation.
Step-by-step explanation:
To break down existing rocks into sediment, processes such as weathering and erosion play a pivotal role. Mechanical weathering includes the physical breakdown of rocks into smaller particles by natural agents like roots, gravity, wind, and water, without altering the rock's mineral composition. Whereas chemical weathering involves the alteration of minerals when rocks come into contact with water solutions and air. Quartz, due to its high resistance to weathering, often predominates as sand grains, while feldspar weathers to clay. Sediment transport occurs through water or air and ceases when the medium (current or wind) can no longer support the particle, depositing it in a new location. Over time, these particles may compact and cement together, undergoing lithification to become clastic sedimentary rocks.
Geologically, no rock is permanent. Igneous, metamorphic, and sedimentary rocks can all be transformed or recycled via the rock cycle. Driven by tectonic plate motion, it's a dynamic process that shifts rocks from one form to another throughout geological time. This process can change solid rock into new forms without melting into magma or through the formation of sediment that may later form new sedimentary rocks. Rocks such as conglomerates, sandstones, and mudstones are examples of the materials formed through these processes.