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Many of the coal fields date to the Carboniferous period of Earth's history. Terrestrial plants also form type III kerogen , a source of natural gas. Although fossil fuels are continually formed by natural processes, they are classified as non-renewable resources because they take millions of years to form and known viable reserves are being ...
Carboniferous is the period during which both terrestrial animal and land plant life was well established. [10] Stegocephalia (four-limbed vertebrates including true tetrapods), whose forerunners (tetrapodomorphs) had evolved from lobe-finned fish during the preceding Devonian period, became pentadactylous during the Carboniferous. [11]
Evidence of coal's use for iron-working in the city during the Roman period has been found. [63] In Eschweiler, Rhineland, deposits of bituminous coal were used by the Romans for the smelting of iron ore. [60] Coal miner in Britain, 1942. No evidence exists of coal being of great importance in Britain before about AD 1000, the High Middle Ages ...
During most of the rest of Carboniferous times, the coal forests were mainly restricted to refugia in North America (such as the Appalachian and Illinois coal basins) and central Europe. At the very end of the Carboniferous, the coal forests underwent a resurgence, expanding mainly in eastern Asia, notably China; they never recovered fully in ...
Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae and other once-living things. These natural deposits of bitumen have been formed during the Carboniferous period, when giant swamp forests dominated many parts of the Earth. [23]
Some cyclothems may have formed as a result of marine regressions and transgressions related to growth and decay of ice sheets, respectively, as the Carboniferous was a time of widespread glaciation in the southern hemisphere. [4] A more general interpretation of sequences invokes Milankovitch cycles. [5] [6]
Outcrop of Ordovician kukersite oil shale, northern Estonia Lower Jurassic oil shale near Holzmaden, Germany. Oil shale geology is a branch of geologic sciences which studies the formation and composition of oil shales–fine-grained sedimentary rocks containing significant amounts of kerogen, and belonging to the group of sapropel fuels. [1]
Fires really took off in the high-oxygen, high-biomass period of the Carboniferous, where the coal-forming forests frequently burned; the coal that is the fossilised remains of those trees may contain as much as 10-20% charcoal by volume. These represent fires which may have had approximately a 100-year repeat cycle.