Carboniferous

Note: This is only a rough draft, with notes. Please do not edit this article until the final draft is complete — i.e., when this notice is removed. You may add comments on what you would like to see included in the discussion area. Rick Swarts 23:40, 3 April 2006 (UTC)

The Carboniferous is a major division of the geologic timescale that extends from the end of the Devonian period, about 359.2 Ma (million years ago), to the beginning of the Permian period, about 299.0 Ma (ICS 2004). 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 of that age found in Great Britain and Western Europe. The first third of the Carboniferous is called the Mississippian epoch, and the remainder is called the Pennsylvanian. Conifer trees were introduced in this important and well-known time period.

Carboniferous period
Mississippian			Pennsylvanian
Lower/Early	Middle	Upper/Late	Lower/Early	Middle	Upper/Late
Tournaisian	Viséan	Serpukhovian	Bashkirian	Moscovian	Kasimovian | Gzhelian

Subdivisions

The Carboniferous is usually broken into Lower and Upper subdivisions. The Faunal stages from youngest to oldest are:

Gzhelian (most recent)

• Noginskian/Virgilian

Kasimovian

• Klazminskian
• Dorogomilovksian/Virgilian
• Chamovnicheskian/Cantabrian/Missourian
• Krevyakinskian/Cantabrian/Missourian

Moscovian

• Myachkovskian/Bolsovian/Desmoinesian
• Podolskian/Desmoinesian
• Kashirskian/Atokan
• Vereiskian/Bolsovian/Atokan

Bashkirian/Morrowan

• Melekesskian/Duckmantian
• Cheremshanskian/Langsettian
• Yeadonian
• Marsdenian
• Kinderscoutian

Serpukhovian

• Alportian
• Chokierian/Chesterian/Elvirian
• Arnsbergian/Elvirian
• Pendleian

Visean

• Brigantian/St Genevieve/Gasperian/Chesterian
• Asbian/Meramecian
• Holkerian/Salem
• Arundian/Warsaw/Meramecian
• Chadian/Keokuk/Osagean/Osage

Tournaisian (oldest)

• Ivorian/Osagean/Osage
• Hastarian/Kinderhookian/Chautauquan/Chouteau

Paleogeography

The southern continents remained tied together in 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 Asia still remained detached.

Rocks and coal

Carboniferous rocks in Europe and eastern North America largely consist of a repeated sequence of limestone, sandstone, shale 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 Revolution 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 bark 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 is 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.

Life

Marine Invertebrates

In the oceans the most important groups are the foraminifera, corals, bryozoa, brachiopods, ammonoids, echinoderms (especially crinoids), and Chondrichthyes (sharks and their relatives).

For the first time Foraminifera take a prominent part in the marine faunas; the large spindle-shaped genus Fusulina and its relatives were abundant in what is now Russia, China, Japan, North America; other important genera include Valvulina, Endothyra, Archaediscus, and Saccammina (the latter common in Britain and Belgium). Some Carboniferous genera are still extant.

The microscopic shells of Radiolaria are found in cherts of this age in the Culm of Devonshire and Cornwall, and in Russia, Germany and elsewhere.

Sponges are known from spicules and anchor ropes, and include various forms such as the Calcispongea Cotyliscus and Girtycoelia, and the unusual colonial glass sponge Titusvillia.

Both reef-building and solitary corals diversify and flourish; these include both rugose (e.g. Canina, Corwenia, Neozaphrentis), heterocorals, and tabulate (e.g. Chaetetes, Chladochonus, Michelinia) forms.

Conularids were well represented by Conularia

Bryozoa are abundant in some regions; the Fenestellids including Fenestella, Polypora, and the remarkable Archimedes, so name becasuse it is in the shape of an archimedan screw.

Brachiopods are also abundant; they include Productids, some of which (e.g. Gigantoproductus) reached very large (for brachiopods) size and had very thick shells, while others like Chonetes were more conservative in form, Athyridids, Spiriferids, Rhynchonellids, are Terebratulids are also very common. Inarticulate forms include Discina and Crania. Some species and genera had a very wide distrubution with only minor variations.

Annelids like Spirorbis and Serpulites are common fossils in some horizons.

Among the mollusca, the bivalves continue to increasing in numbers and importance. Typical genera include Aviculopecten, Posidonomya, Nucula, Carbonicola, Edmondia, and Modiola

Conocardium is a common Rostoconch

Gastropods are also numerous, including the genera Murchisonia, Euomphalus, Naticopsis.

Nautiloid cephalopods are represented by tightly coiled nautilids, with straight shelled and curved shelled forms becoming increasingly rare. Goniatite Ammonoids are common.

Trilobites are rare, represented only by the proetid group. Ostracods such as Cythere, Kirkbya, and Beyrichia are abundant.

Amongst the echinoderms, the crinoids were the most numerous. Dense submarine thickets of long-stemmed crinoids appear to have flourished in shallow seas, and their remains were consolidated into thick beds of rock. Prominent genera include Cyathocrinus, Woodocrinus, and Actinocrinus. Echinoids such as Archaeocidaris and Palaeechinus were also present. The Blastoids, which included the Pentreinitidae and Codasteridae and superficially resembled crinoids in the possesion of long stalks attached to the sea-bed, attain their maximum development at this time.

Fish

Many fish inhabited the Carboniferous seas; predominantly Elasmobranchs, sharks with crushing pavement-likes teeth (Psammodus), adapted for grinding the shells of brachiopods, crustaceans, and other marine organisms. Other sharks had piercing teeth, such as the Symmoriida; some, the petalodonts, had peculiar cycloid cutting teeth. Most of the sharks were marine, but the Xenacanthida invaded fresh waters of the coal swamps. Among the bony fish, the Palaeonisciformes found in coastal waters also appear to have migrated to rivers. Sarcopterygian fish were also prominant, and one group, the Rhizodonts, reached very large size.

Most species of Carboniferous marine fish have been described largely from teeth, fin spines and dermal ossicles, with smaller freshwater fish preserved whole.

Freshwater fishes were abundant, and include the genera Ctenodus, Uronemus, Acanthodes, Cheirodus, and Gyracanthus.

Plants

Early Carboniferous land plants were very similar to those of the preceding Latest Devonian, but new groups also appeared at this time.

The main Early Carboniferous plants were the Equisetales (Horse-tails), Sphenophyllales (vine-like plants), Lycopodiales (Club mosses), Lepidodendrales (scale trees), Filicales (Ferns), Medullosales (previously included in the "seed ferns", an artificial assemblage of a number of early gymnosperm groups) and the Cordaitales. These continued to dominate throughout the period, but during Late Carboniferous, several other groups, Cycadophyta (cycads), the Callistophytales (another group of "seed ferns"), and the Voltziales (related to and sometimes included under the conifers), appeared.

The Carboniferous lycophytes of the order Lepidodendrales, which are cousins (but not ancestors) of the the tiny club-moss of today, were huge trees with trunks 30 meters high and upto 1.5 meters in diameter. These included Lepidodendron (with its fruit cone called Lepidostrobus), Halonia, Lepidophloios and Sigillaria. The roots of several of these forms are known as Stigmaria.

The fronds of some Carboniferous ferns are almost identical with those of living species. Probably many species were epiphytic. Fossil ferns and "seed ferns" include Pecopteris, Cyclopteris, Neuropteris, Alethopteris, and Sphenopteris; Megaphyton and Caulopteris were tree ferns.

The Equisetales included the common giant form Calamites, with a trunk diameter of 30 to 60 cm and a height of upto 20 meters. Sphenophyllum was a slender climbing plant with whorls of leaves, which was probably related both to the calamites and the lycopods.

Cordaites, a tall plant (6 to over 30 meters) with strap-like leaves, was related to the cycads and conifers; the catkin-like inflorescence, which bore yew-like berries, is called Cardiocarpus. These plants were thought to live in swamps and mangroves. True coniferous trees (Waichia, of the order Voltziales) appear later in the Carboniferous, and preferred higher drier ground..

Freshwater and Lagoonal Invertebrates

Freshwater Carboniferous invertebrates include various bivalve molluscs that lived in brackish or fresh water, such as Anthracomya, Naiadiles, and Carbonicola; diverse Crustacea such as Bairdia, Carbonia, Estheria, Acanthocaris, Dithyrocaris, and Anthrapalaemon.

The Eurypterids were also diverse, and are represented by such genera as Eurypterus, Glyptoscorpius, Anthraconectes, Megarachne (originally misinterpreted as a giant spider) amd the specialised very large Hibbertopterus Many of these were amphibious.

Frequently a temporary return of marine conditions resulted in marine or brackish water genera such as Lingula, Orbiculoidea, and Productus being found in the thin beds known as marine bands.

Terrestrial Invertebrates

Fossil remains of air-breathing insects, myriapods and arachnids are known from the Late Craboniferous, but so far not from the Early Carboniferous. Their diversity when they do appear however show that these arthropods were both well developed and numerous. Among the insect groups are the Syntonopterodea (relatives of present-day mayflies), the abundant and often large sap-sucking Palaeodictyopteroidea, the huge predatory Protodonata (griffinflies), the diverse herbivorous "Protorthoptera", and numerous basal Dictyoptera (ancestors of cockroaches). Many insects have been obtained from the coalfields of Saarbruck and Commentry, and from the hollow trunks of fossil trees in Nova Scotia. Some British coalfields have yielded good specimens: Archaeoptitus, from the Derbyshire coalfield, had a spread of wing extending to more 35 cm; some specimens (Brodia) still exhibit traces of brilliant wing colors. In the Nova Scotian tree trunks land snails (Archaeozonites, Dendropupa) have been found.

Tetrapods

Carboniferous amphibians were diverse and common by the middle of the period. They included a number of basal tetrapod groups classified in early books under the Labyrinthodontia. These had long bodies, a head covered with bony plates and weak or undeveloped limbs. The largest were over 2 meters long. They were accompanied by an assemblage of smaller amphoibians included under the Lepospondyli, often only about 15 cm long. Some were aquatic and lived in rivers (Loxomma, Eogyrinus, Proterogyrinus); others may have been semi-aquatic (Ophiderpeton, Amphibamus) or terrestrial (Dendrerpeton, Hyloplesion, Tuditanus, Anthracosaurus).

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. These included the earliest Sauropsid reptiles (Hylonomus), and the earliest known Synapsida (Archaeothyris). These small lizard-like animals quiickly gave rise to many descendents. The amniote egg allowed these ancestors of all later birds, mammals, and reptiles to reproduce on land by preventing the desiccation, or drying-out, of the embryo inside.

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.

See also

• Calamites - a tree-sized horsetail that was common in the Carboniferous
• Important Carboniferous Lagerstätten
  • Hamilton Quarry; 320 mya; Kansas, US
  • Mazon Creek; 300 mya; Illinois, US

External links

• Geologic Time Scale 2004. International Commission on Stratigraphy (ICS). Retrieved September 19, 2005.

Carboniferous period
Mississippian			Pennsylvanian
Lower/Early	Middle	Upper/Late	Lower/Early	Middle	Upper/Late
Tournaisian	Viséan	Serpukhovian	Bashkirian	Moscovian	Kasimovian | Gzhelian

ca:Carbonífer cs:Karbon cy:Carbonifferaidd da:Kultiden de:Karbon (Geologie) et:Karbon es:Carbonífero fr:Carbonifère it:Carbonifero he:קרבון lt:Karbonas nl:Carboon ja:石炭紀 no:Karbon (geologi) pl:Karbon (okres) pt:Carbonífero ru:Каменноугольный период sl:Karbon fi:Kivihiilikausi sv:Karbon zh:石炭纪

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

• Carboniferous  ^history

The history of this article since it was imported to New World Encyclopedia:

• History of "Carboniferous"

Note: Some restrictions may apply to use of individual images which are separately licensed.