Soil deposition

The geological cycle is driven by thermal and tectonic processes in the earth's mantle and crust which shape the landscape, and climate and changes in sea level. The climate, bedrock and landscape control the sediment supply. Gravity causes ground movement (creep, falls, slips, and flows). Rainfall, rivers and streams, and wave action erodes rock and soil transporting the particles to be deposited in rivers, and on alluvial fans, floodplains, deltas, and coastal plains. Ice deforms or erodes the substrate as it moves forward. Glacial debris is deposited beneath the advancing ice as till. As the ice melts, glacial debris is carried by the melt water to form glaciofluvial, glaciolacustrine and glaciomarine deposits. Wind moves soil particles and volcanic ash by traction/surface creep, saltation, or in suspension to form aeolian deposits. Soil particles in a marine environment are transported by wave action, tidal currents, subsea slope failures, turbidity currents and in suspension. The transport process and the depositional environment affect the composition, fabric, structure and properties of soil. Once a soil is deposited the upper layers at the time are subject to weathering which means it undergoes further changes. The soil may be subject to further cycles of erosion, transportation and deposition.