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| This period is part of the Paleozoic era. |
| Permian |
| Carboniferous |
| Devonian |
| Silurian |
| Ordovician |
| Cambrian |
The Carboniferous is a major division of the geologic timescale that extends from the end of the Devonian period (about 280 million years before the present (BP)) to the beginning of the Permian period (about 340 million Years BP). As with most older geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by 5-10 million years. The Carboniferous is named for the extensive coal beds from that age in England and Western Europe. In North America, the first third of the Carboniferous is called the Mississippian period and the remainder is called the Pennsylvanian.
The Carboniferous is usually broken into lower and upper subdivisions. The Faunal stages from youngest to oldest are:
The southern continents remained tied together into the supercontinent Gondwana, which collided with North America-Europe ( Laurussia) along the present line of eastern North America. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although pieces of present east AsiaThe continent of Asia is defined by subtracting Europe and Africa from the great land mass of Africa-Eurasia. The boundaries are vague, especially between Asia and Europe: Asia and Africa meet somewhere near the Suez Canal. The boundary between Asia and E still remained detached.
Carboniferous rocks in EuropeFor the band of the same name, see Europe (band . Europe is a continent forming the westermost part of the Eurasian supercontinent. Europe is bounded to the north by the Arctic Ocean, to the west by the Atlantic Ocean, to the south by the Mediterranean Se and eastern North America largely consist of a repeated sequence of limestoneshale overlaid by limestone. Cumberland Plateau, Tennessee Limestone is a sedimentary rock composed of mineral calcite (calcium carbonate). The primary source of this calcite is usually marine organisms. These organisms secrete shells that settle out of t, sandstoneSandstone is an arenaceous sedimentary rock composed mainly of feldspar and quartz and varies in colour (in a similar way to sand), through grey, yellow, red, and white. Since sandstones often form highly visible cliffs and other rock formations, certain, shaleShale is a fine-grained sedimentary rock whose original constituents were clays or muds. It is characterized by thin laminae breaking with an irregular curving fracture, often splintery, and parallel to the often indistinguishable bedding planes. Non-fiss and coal beds. In North America, the early Carboniferous is largely marine limestone, which accounts for the division of the Carboniferous into two periods in North American schemes. The Carboniferous coal beds provided much of the fuel for power generation during the Industrial RevolutionThe Industrial Revolution is the name given to the massive social, economic, and technological change in 18th century and 19th century Great Britain. It commenced with the introduction of steam power (fuelled primarily by coal) and powered, automated mach and are still of great economic importance.
The large coal deposits of the Carboniferous primarily owe their existence to two factors. The first of these is the appearance of barkFor other meanings of bark see Bark (disambiguation). Bark is the outermost layer of stems and roots of woody plants such as trees. It overlays the wood and consists of three layers: the cork, the phloem, and the vascular cambium in other words, most of t bearing trees (and in particular the evolution of the bark fiber lignin). The second is the lower sea levels that occurred during the Carboniferous as compared to the Devonian period. This allowed for the development of extensive lowland swamps and forests in North America and Europe. It has been hypothesized that large quantities of wood were buried during this period because animals and decomposing bacteria had not yet evolved that could effectively digest the new lignin. It has also been observed that the extensive burial of organically produced carbon led to a buildup of surplus oxygen in the atmosphere resulting in concentrations up to 80% higher than today. The oxygen increase is implicated in increased wildfire activity, as well as the expression of gigantism in certain insects and amphibians, whose size are constrained by respiratory systems that are limited in their ability to diffuse oxygen.
In eastern North America, marine beds are more common in the older part of the period than the later part and are almost entirely absent by the late Carboniferous. More diverse geology existed elsewhere of course. Marine life is especially rich in crinoids and other echinoderms. Brachiopods were abundant. Trilobites became quite uncommon. On land, large and diverse plant populations existed. Land vertebrates included large amphibians.
One of the greatest evolutionary innovations of the Carboniferous was the amniote egg, which allowed for the further exploitation of the land by certain tetrapods. The amniote egg allowed the ancestors of birds, mammals, and reptiles to reproduce on land by preventing the desiccation, or drying-out, of the embryo inside.
Geologic timescale