Buried rock fragments may be further subjected to processes of weathering that cause them to break down into smaller particles or soil, or they may become new rocks through the sedimentary process. The sedimentary process requires time and pressure to create new rocks from rock fragments and sediment.
Rock fragments are typically small pieces of a larger rock formation that have been broken off through erosion by external forces such as fluctuating temperatures, ice, rain or excessive moisture. These fragments may then be transported to new regions where they are deposited and allowed to settle. Over time, the fragments may be buried by new sediment, which allows the process of lithification to begin due to the weight of the new soil. Lithification involves the compaction and cementation of sedimentary materials, which may lead to the creation of new rocks over time.
The size of the rock fragments and the type of weathering that eroded their source rock can affect the type of sedimentary rocks into which they may form. Conglomerate rocks and breccia are formed from larger sized rock fragments such as boulders and pebbles, which are typically found closer to their source rock formation due to their weight. Finer sediments, such as sand, clay and silt, are deposited further from their source and may form into sandstone, shale or siltstone.