Peat, Its Origins, Characteristics, and Geological Transformations

• Main Author: Rich, Fredrick J.
• Format: Text
• Language: unknown
• Published: Digital Commons@Georgia Southern 2015
• Subjects: Coal; Everglades; Hydrosere; Okefenokee; Palynology; Peat; Petrograph; Wetlands; Geography; Geology; Arctic
• Online Access: https://digitalcommons.georgiasouthern.edu/geo-facpubs/122; https://doi.org/10.1016/B978-0-444-59510-2.00002-1

Peat is a naturally existing sedimentary material that is both common and unusual; its origins are due to botanical and geological processes, and significant contributions to any peat deposit are attributable to animals, plants, and diverse groups of microbial taxa. Peat deposits develop where the accumulated remains of biological communities exceed the capacity of the environment to destroy or recycle those components; otherwise individual peats have little in common. Many peats represent sediment accumulation under the cold conditions of the Arctic, though temperate peats are abundant in such places as Ireland, and subtropical peats have developed for thousands of years in the Okefenokee Swamp and the Everglades in the southeastern US. As a sediment composed of discrete particles, peat could only have accumulated after plants, particularly, had developed the capacity to remain intact after plant parts had been deposited as sedimentary debris. The development of woody tissue, waxy cuticle, and, eventually, spores, pollen, and resins eventually lead to the formation of vast amounts of chiefly botanical debris after the initiation of the Carboniferous Period. The steady evolution of plant groups from mosslike organisms, to tree-sized ferns, conifers, and, eventually angiosperms such as Sassafras allowed for a continuous and highly variable accumulation of sediments that we know as coal. Diagenetic changes in peats, attributable to microbial activity, geochemical changes in the environments of deposition, and the intervention of geological processes including increased heat, lithostatic pressure, and metamorphism have lead to a wide variety of coals being available for human use. These might be known as lignite, bituminous coal, or anthracite, but they all owe their origins to the presence of microbes and plants that could produce geologically durable remains.