Search results
Results From The WOW.Com Content Network
Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times. [3] [4] Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution.
Coal forms when organic matter builds up in waterlogged, anoxic swamps, known as peat mires, and is then buried, compressing the peat into coal. The majority of Earth's coal deposits were formed during the late Carboniferous and early Permian. The plants from which they formed contributed to changes in the Carboniferous Earth's atmosphere. [25]
It is also found as fossil fuels in coal and petroleum and gas. Native forms of carbon are much rarer, requiring pressure to form. Pure carbon exists as graphite or diamond. [1] The deeper parts of Earth such as the mantle are very hard to discover. Few samples are known, in the form of uplifted rocks, or xenoliths.
The coal forests seem to have been areas of flat, low-lying swampy areas with rivers flowing through from higher, drier land. [4] When the rivers flooded, silt gradually built up into natural levees. Lakes formed as some areas subsided, while formerly wet areas became dry from silt buildups.
Coal – Combustible sedimentary rock composed primarily of carbon; Geology – Scientific study of Earth's physical composition; Mineralogy of Mars – Overview of the mineralogy of Mars; Oil shale – Organic-rich fine-grained sedimentary rock containing kerogen; Ore genesis – How the various types of mineral deposits form within the Earth ...
Since carbon (coal) is a good absorber of radiation, it might be possible to convert some abandoned underground coal mines in the upper Allegheny region to helium-creation plants by providing a ...
Epithermal — mineral ore deposits formed at low temperatures (50–200 °C) near the Earth's surface (<1500 m), that fill veins, breccias, and stockworks. [2] Telethermal — mineral ore deposits formed at shallow depth and relatively low temperatures, with little or no wall-rock alteration, presumably far from the source of hydrothermal ...
When life started to form around 4 billion years ago, Earth was oxygen-free. Then the advent of photosynthesis came about, which was great for life on Earth but not so great for Lang's research.