Carboniferous

The Carboniferous (/ˌkɑːr.bəˈnɪf.ər.əs/ KAHR-bə-NIF-ər-əs)[6] is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period 358.9 million years ago (Mya), to the beginning of the Permian Period, 298.9 Mya. The name Carboniferous means "coal-bearing", from the Latin carbō ("coal") and ferō ("I bear, I carry"), and refers to the many coal beds formed globally during that time.[7]

Carboniferous
358.9 ± 0.4 – 298.9 ± 0.15 Ma
Chronology
Etymology
Name formalityFormal
Nickname(s)Age of Amphibians
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitPeriod
Stratigraphic unitSystem
First proposed byWilliam Daniel Conybeare and William Phillips, 1822
Time span formalityFormal
Lower boundary definitionFAD of the Conodont Siphonodella sulcata (discovered to have biostratigraphic issues as of 2006)[2]
Lower boundary GSSPLa Serre, Montagne Noire, France
43.5555°N 3.3573°E / 43.5555; 3.3573
GSSP ratified1990[3]
Upper boundary definitionFAD of the Conodont Streptognathodus isolatus within the morphotype Streptognathodus wabaunsensis chronocline
Upper boundary GSSPAidaralash, Ural Mountains, Kazakhstan
50.2458°N 57.8914°E / 50.2458; 57.8914
GSSP ratified1996[4]
Atmospheric and climatic data
Mean atmospheric O
2
content
c. 32.3 vol %
(162 % of modern)
Mean atmospheric CO
2
content
c. 800 ppm
(3 times pre-industrial)
Mean surface temperaturec. 14 °C
(0 °C above modern)
Sea level above present dayFalling from 120 m to present-day level throughout the Mississippian, then rising steadily to about 80 m at end of period[5]

The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822,[8] based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian.[9]

Terrestrial animal life was well established by the Carboniferous period.[10] Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, diversified during the Carboniferous, including early amphibian lineages such as temnospondyls, with the first appearance of amniotes, including synapsids (the group to which modern mammals belong) and reptiles during the late Carboniferous. The period is sometimes called the Age of Amphibians,[11] during which amphibians became dominant land animals and diversified into many forms including lizard-like, snakelike and crocodile-like.[12]

Insects would undergo a major radiation during the late Carboniferous. Vast swaths of forest covered the land, which would eventually be laid down and become the coal beds characteristic of the Carboniferous stratigraphy evident today. The atmospheric content of oxygen reached its highest levels in geological history, 35%[13] compared with 21% today, allowing terrestrial invertebrates, which breathe by diffusion of oxygen through spiracles, to grow very large.[13]

The later half of the period experienced glaciations, low sea level, and mountain building as the continents collided to form Pangaea. A minor marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred at the end of the period, caused by climate change.[14]