Weathering is the process of larger rocks breaking down into smaller pieces. It is the first step in transforming bedrock into sediment through diverse physical and chemical processes. The importance of each process varies depending on the environmental conditions and the rock type.
As the bedrock breaks down into smaller pieces, the grains are more easily transported. When transport occurs depends on the air, water, or ice flows in the area or a potential collapse of a slope to produce a gravity flow. The initial transport processes vary significantly depending on the environment and local topography.
Sedimentary grains continue to weather as they are transported through various depositional environments and after they are deposited. The weathering processes vary depending, again, on the environmental conditions and the composition of the grains.