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L. 3 Earth Changes
Term | Definition |
---|---|
peat | a mixture of water and plant materials that will eventually form coal if the conditions are right, as in a swamp that will eventually become buried under layers of sediment |
fossil fuels | substances formed from organisms that lived on Earth millions of years ago |
natural gas | a fossil fuel that has become gaseous as a result of heat and chemical reactions |
petroleum | a liquid fossil fuel that results from Earth processes that compact sediment on top of decaying marine organisms that lived millions of year ago |
lignite | a soft, dark brown coal that is formed in the second stage of coal development |
coal | a sedimentary rock formed over millions of years from organisms subjected to heat and pressure and is used as fuel |
bituminous coal | also known as soft coal, has become compressed for a very long time, and when burned, produces many pollutants |
anthracite | the fourth and final stage in coal formation, is hard coal produced as a result of extreme pressures and heat applied by the Earth's crust |
ores | rocks and minerals found in quantities large enough to make them worth mining |