What is a layer of organic sediment?

Organic matter in soil is compacted by the weight of new soil, created by decaying matter, into an organic sediment layer called peat. Given enough time, this peat becomes overrun with minerals from underground water until it becomes one of many types of sedimentary rock, including shale and limestone.

The peat contains nutrients that make a very effective fertilizer, and the peatland ecosystem is argued to be the world's best carbon sink, pulling more CO2 from the atmosphere than it produces in a one year timespan. Over thousands of years, the carbon added to the peat grows the biomass to proportions that can be used in an industrial manufacturing setting.