The Carboniferous Period

The Carboniferous Period

358.9 million years ago - 298.9 million years ago

Terrain

Animals

Plants

Click the mountains to learn about Earth's geography

Click the crab to learn about animal life on Earth

Click the fern to learn about plant life on Earth

338.9 MYA

313MYA

298.9 MYA

The Devonian Period

ThePermian Period

323MYA

298.9MYA

358.9 MYA

Climate

Sources

Atmosphere

Click the thermometer to learn about the Earth's climate

Click the map to seemy sources

Click the cloud to learn about the Earth's atmosphere

338.9 Million Years Ago

The End of Romer's Gap

Romer's Gap kicked off at the very start of the Carboniferous Period. As the name suggests, it is a gap - a gap in the fossil record that lasted for about 20 million years. Little fossil evidence is available from the early Carboniferous Period. We know a fair amount about the creatures and flora that lived prior to and proceeding this time-chasm, but it is unclear what evolutions were taking place during the gap. It is speculated that the radiations were major, due to the diversity seen in fossils from after the gap.

Animals

Pictured here is the species Orthacanthus, a freshwater shark that evolved in this period. Both this and the Cladoselache (another shark), were representatives of the chondrichthians (cartilage skeleton). Osteichthians (bony skeleton), such as crossopterygians, dipnoi, and palaeoniscoids also occupied freshwater environments.

The Devonian Extinction Events led to many of the animals from that time dying out, including the placoderms (armored fish), leaving a vacuum for other creatures to fill. Other fish took the placoderm's place, amphibians flourished, and reptiles evolved into existence.

Hylonomus, thought to be the first reptile. The earlies evidence of reptiles comes from fossils found in a tree in Nova Scotia, dated to the late Pennsylvanian.

Labyrinthodontia, one of the many predominant amphibians of the Carboniferous Period. Amphibians stayed near water so that they could lay their eggs without the eggs drying out. None of these amphibians have living relatives today.

358.9 Million Years Ago

The Beginning of the Mississippian Subperiod

A series of extiction events ended the Devonian Period, mainly caused by dropping oxygen levels. Many of the species that thrived during said period died off, and this includes marine life such as the armored fish, placoderms. Amphibians flourished, reptiles emerged, insects became huge, the climate was becoming warm and humid, Pangea was in the process of amalgamating, and plants were about to go crazy. Buckle your seatbelts, ladies and gentlemen. Welcome to the Carboniferous Period.

323 Million Years Ago

The Pennsylvanian Subperiod

Fossil evidence shows that the climate was fluctuating between dry and cool and humid and hot, due to some plants being more dry-adapted whereas others have been discovered to be more wet-adapted. Coal beds dated to this time are also much thinner than coal beds from earlier in the Carboniferous period, further pointing to the climate becoming dryer. These are the conditions that slowly but surely spelled doom for the large rainforests that dominated the Carboniferous.

A coal bed!

298.9 Million Years Ago

The Carboniferous Rainforest Collapse (CRC)

So much carbon dioxide had been absorbed by the global rainforests that there wasn't enough CO2 in the atmosphere to keep the Earth warm enough to support these rainforests. Couple that with the fact that CO2 kept getting trapped in glacial deposits, lessening the concentration of CO2 even further, as well as the full formation of Pangea completely cutting off the supply of rain to the more interior land regions, and the writing was on the wall for the massive Carboniferous rainforests. Their collapse ended the Carboniferous Period.

Bibliography

• https://www.britannica.com/science/Carboniferous-Period

• https://www.darwinsdoor.co.uk/timetour/the-carboniferous-period.html

• https://www.youtube.com/watch?v=d_ATQsL3NMU

• https://www.pbs.org/video/when-the-rainforests-collapsed-tholej/

Atmosphere

The Earth's atmosphere was full of carbon dioxide at the start of the Carboniferous Period - about 1500 parts per million. This is what allowed plants to go as crazy as they did. As CO2 was both used up by the rainforests and trapped in ice, the rainforests were still pumping out so much oxygen that at its peak in the late Carboniferous, atmospheric oxygen composition reached a staggering 35%.

313 Million Years Ago

Cyclothems

The dropping CO2 levels caused the global temperature to drop with it, and with the global temperature decreasing, glaciers began to form. Coal cyclothems (repeated sequences of distinctive sedimentary rock layers) were produced throughout the Northern Hemisphere by the Gondwanan glaciations, and these cyclothems contain the majority of the world's coal reserves.

Lycopods were tree-like plants that grew dense and spirally-arranged leaves. They reproduced using either cones or spores. Some lycopods had actual trunks similar to the modern tree.

Cordaites are now extinct, but they were the precursors to conifers. They favored drier, more upland environments.

Plants

Vascular land plants were the dominant form of plant life on Earth during the Carboniferous Period. Carboniferous forests included lycopods, sphenopsids, cordaites, seed ferns, and true ferns. Click the images for more information about these plants.

Sphenopsids are "trees" and shrubs with a disjointed stem and spiraling leaves. The only living representative of the sphenopsids is the Equisetum.

Seed ferns are similar to today's ferns, but they reproduced using actual seeds rather than spores. They have no living relatives today.

Terrain

Land on Earth during the Carboniferous Period was pretty hectic. Pangea was forming and dropping temperatures were causing glaciers to form, lowering sea levels.

A theoretical map of present-day Earth if sea level was lower

Approx. 298.9 Million Years Ago

The Formation of Pangea is Complete

Pangea began to take shape around the beginning of the Pennsylvanian Subperiod, but finished forming right before the end of the Carboniferous Period (probably because it was one of the things that factored into the period ending). It formed when the paleocontinents Laurentia and Baltica mashed together to form Euramerica, and then that landmass combined with the more southern paleocontinent Gondwana to form the supercontinent that we all know and love today - Pangea.

Climate

Earth's climate started out very warm and wet due to the excess of CO2 in the atmosphere. With the heavy consumption of CO2 by the massive rainforests (and subsequent overproduction of oxygen), loss of CO2 to glaciation, and eventually the formation of Pangea cutting off rain to the more inland areas, the climate was very cool and dry by the end of the Carboniferous Period. During the Pennsylvanian Subperiod there was some fluctuation between hot and humid and cold and dry until Pangea formed and the CRC occurred.