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How does peat form in swamps before it becomes coal?

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coal utilization Cross-regenerative coke oven. (A) Cross section, showing the alternating arrangement of flue walls and ovens; (B) longitudinal section, showing (left) a series of combustion flues in a single flue wall and (right) part of a long, slotlike oven.

Peat forms in wetlands such as swamps, bogs, and moors through the partial decomposition of organic matter, primarily plant material. This process, known as biochemical coalification, occurs in waterlogged, anaerobic (oxygen-poor) conditions that prevent the complete decay of organic debris.12

For thick peat deposits to accumulate, specific environmental conditions must be met:
* Climate: Warm, moist conditions generally favor plant growth and the preservation of organic material, though peat can also form in colder regions.12
* Hydrology: The area must remain moist, with annual precipitation often exceeding evaporation to maintain waterlogged soils.1
* Physical Environment: Slow, continuous subsidence and protection from excessive sediment influx or frequent inundation allow plant material to build up over time.1

In these stagnant environments, microorganisms break down plant matter near the surface where oxygen is available; however, at greater depths, the lack of oxygen limits microbial activity, allowing the partially decomposed material to persist as peat. Once this peat is buried by further sediment, the geochemical coalification process begins, eventually transforming it into coal.12