FOR 60m years or so of Earth’s history, a period known to geologists as the Carboniferous, plant life seemed unwilling to rot. When trees died they fell to the ground, much of which was swampy in those days, and instead of being consumed by micro-organisms they remained more or less intact. In due course, more trees fell on them. And more, and yet more. The buried wood, pressed by layers of overburden and heated from the Earth’s interior, gradually lost its volatile components and was transformed into a substance closer and closer to pure carbon.
The result was the coal that fuelled the Industrial Revolution, providing power for factories and railways, heat for hearths, gas for lighting, a reducing agent for turning ore into iron and steel, the raw ingredients for drugs, dyes and other chemicals, and the energy that has generated most of the world’s electricity. Yet the abundance of this Carboniferous coal is a puzzle. Forests began in the Devonian, the period before the Carboniferous, and have existed ever since. But, though not all coal is Carboniferous, the spike in coal accumulation in that period is, as the chart shows, far...Continue reading
Source: Science and technology http://ift.tt/1U85cMH
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