Peat is formed from organic material that is only partially decomposed due to anaerobic conditions. The decomposition process occurs very slowly, causing organic matter to accumulate and form the peat layer.
The process of peat formation takes place over thousands of years, beginning with a very large basin or puddle of water silting slowly and gradually over time. Silting occurs as plants that grow in the wetlands (organic materials) die, accumulate at the bottom of the basin, then undergo slow decay due to the absence of air.
These organic materials then form a layer on top of the mineral soil at the bottom of the basin. Subsequent plants grow and then die on top of the established layer, gradually forming new layers of peat. In general, peat is found in waterlogged areas such as swamps, basins between rivers, and coastal areas.