Coal forest

From Wikipedia, the free encyclopedia

The Coal Forests is an informal term referring to the vast swathe of wetland forests that extended over much of the tropical land areas during Late Carboniferous (Pennsylvanian) and Permian times. These forests got their name because they accumulated enormous deposits of peat which later changed into coal. As much of the carbon in this enormous amount of peat came from photosynthesis splitting existing carbon dioxide, it is thought that the accompanying split-off oxygen went into the atmosphere, greatly increasing its ppO2: one estimate says to about 35%, making it easier for animals to breathe air as a source of oxygen, as seen in the size of Meganeura compared to modern dragonflies.

During Middle Pennsylvanian times, the Coal Forests mainly covered tropical Euramerica (Europe, eastern North America, northwesternmost Africa). At the end of Middle Pennsylvanian times, however, much of the Euramerican Coal Forests disappeared, probably as a response to regional mountain building (the Variscan orogeny) causing changes to river drainage and water tables. This contraction of the Coal Forests coincided with a marked period of global warming and a notable contraction of the polar ice covering southern Gondwana. Although there is still some disagreement, the removal of large areas of this fast-growing vegetation may have caused a rapid build-up of atmospheric CO2, which in turn may have increased global temperatures through the Greenhouse effect.

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 period, however, the Coal Forests underwent a resurgence, expanding mainly in eastern Asia, notably China; they never recovered fully in Euramerica. The Chinese Coal Forests continued to flourish well into Permian times. This resurgence of the Coal Forests in very late Carboniferous times seems to have coincided with a lowering of global temperatures and a return of extensive polar ice in southern Gondwana, perhaps due to lessening of greenhouse effect due to massive coal deposition abstracting much carbon dioxide from the atmosphere.

Some of the characteristic plants of the Coal Forests were:

[edit] References and further reading

[edit] Links to reconstruction images of coal forest

 This botany article is a stub. You can help Wikipedia by expanding it.