Coal, steam and steel: How geology made the industrial revolution

Before the 18th century, everything in the world was organic, artisan and handcrafted, because there was no other way. Weavers made clothes, blacksmiths made tools and nails, farmers went behind the plough.

This is not to say that the world stood still. Compare your image of the Viking time with the middle ages, with the renaissance and the early 18th century. The great advances in construction, ship building, weaponry and agricultural practice become clear. During the middle ages, man had learned to harness wind and water power for grain mills, timber saws and water pumps. But each item still had to be made by hand, and moved by human, horse or wind power, as it had been for thousands of years. At sea, ships were at the mercy of the wind gods. Until the steam engine changed everything.

Already in 1712, Thomas Newcomen constructed the first steam engine to pump water from mines. But his steam engine required the water to boil and cool again in the cylinder for each pumping stroke. It was slow and ate lots of coal.

The big leap came with the man who more than any other became synonymous with the industrial revolution: The Scottish engineer James Watt. He made the first steam engine as we know it: water is heated to steam, enters the cylinder through valves, pushes the piston, exits through another valve and thereafter condenses separately. The piston chamber now had continuous access to steam, and could work much faster, and save fuel. Watt added the rod to a flywheel, which transferred the piston’s back-and-forth to a circular motion. The rest is history.

The steam engine was the literal engine of the industrial revolution. It gave power to heavier and faster machines, and provided faster and more reliable transport on land and at sea. “The Rocket”, the first reliable steam locomotive, may sound ironic to us modern people. Its top speed was 45 km/h. But in 1829 The Rocket was a revolution. It worked in all kinds of weather, regardless of wind and current. The Rocket ran the first leg of that magic carpet made of steel, which would cover the globe.

Why did the industrial revolution start in Great Britain? Historians have written large volumes on the topic, and it would be futile to try to give it a fair treatment in a blog post. Neither am I a historian or economist.

But, generally, historians agree that the revolution happened in England because of fortunate political circumstances, with history all the way back to the Magna Carta in 1215. From the Magna Carta gave the noblemen and the church some rights to fair trials and “no taxation without representation”, a red thread goes towards the development of the institutions we know today: Parliament, independent courts and rule of law. This thread was slow, long, winding and often brutal, even with civil wars fought between the king and the noblesse. But in the 18th century, these institutions were well established. Not as democracy as we know it, of course. But the king’s power was limited, and the law protected the activities of land owners and businessmen – and their rights to property.

Property rights are crucial to economic development. Inventing a steam machine is one thing, but building factories demands investment. Nobody wants to invest if they risk losing it to the whims of a king or local lord. England had the framework in place.

Which brings us to the other, literal ingredients of the industrial revolution: Iron to build the engines and coal to power them, and other metals for special parts. The United Kingdom had them all.

Iron ore and coal are common across Europe, but they are not fairly distributed to everyone. Norway and Sweden have lots of iron ore, but almost no coal, and we were soaked in the rule of autarchy kings. Here at home, in Denmark-Norway, one could not even open an inn without royal privilege.

France had lots of both coal and iron, but it was stuck in L’Ancien Regime with nutty kings in the Versailles and mercantilism to rule the cconomy.

The industrial revolution demanded both the natural resources and the institutional framework. England was the place, which had both. So, let’s look at the where’s and when’s of coal and iron in England: The geology of the industrial revolution. Where are the coal, iron and metals, and why is it there?

Let’s start with the coal, because it is the easiest to understand. Once upon a time, coal covered much of Britain – and much of Europe. In fact, much of the world was a large coal factory, made up of swamps and forests. The time was around 330 to 300 million years ago, at the late half of the period which has gotten its name after the coal: The Carboniferous.

The main reason for all this coal was evolution.

We don’t know exactly when plants first went on land, but the first fossil spores suggest that it happened in the Middle Ordovician, around 470 million years ago. We know them mainly through spores, and they were somthing like modern liverworths. Weak, no roots and no vascular system, meaning that they had to live in water or very wet environments, since they could not transport water throug stem and branches.

It was not until the Middle Silurian, around 430 million years ago, that the first certain vascular plants appeared – that is, plants which have veins in their stem and branches, to transport water around. Cooksonia were from a few millimeters to centimeters long, and looked basically like a branched stem with a small spore cup on each end.

Cooksonia sp. - MUSE
The pioner: Tiny Cooksonia was the great-great-grandfather of pineapple, chili and poison ivy. (MUSE [CC BY-SA 3.0 (], via Wikimedia Commons>)

Through the Silurian and into the next period, the Devonian, plants spread far and wide, a botanical home alone party on the open Earth.

Plants developed lignine, the stiff compound that becomes cellulose, which enabled them to grow taller. First thin stems, which grew thicker through the Devonian, and finally grew to full tree size at the beginning of the Carboniferous.

Stems grew in concert with the development of roots. The first plants had basically no roots, and could not stand up. Through the Devonian, roots bored deeper, and made it possible for plants to stand upright and rise towards the sky.

Plants also made another major development at the beginning of the Devonian, around 410 million years ago: Leaves. The first leaves were only a millimeter or two in size. Through the Devonian, that was it. The reason may, paradoxically, be the function of leaves themselves:

Leaves catch sun light and heat, breathe CO2 in and water vapor and oxygen out, to drive photosynthesis. But the Devonian was a very warm time, so larger leaves might catch so much heat that it would kill the plant. The Devonian atmosphere had around 0,002% CO2, five times more than today, so plants did not need big leaves to extract CO2 for photosynthesis, either.

But, by doing photosynthesis, the plants also prepared the ground and the atmosphere for getting bigger. Slowly, they extracted CO2 and buried it in the ground, as plant remnants – the first coal. Removing CO2 reduced the greenhouse effect, pushed the evolutionary snowball to roll: Leaves grew bigger, stems grew taller and all this biomass extracted CO2 from the atmosphere, gradually cooling the Earth. Which, in turn, made leaves larger and stems taller and thicker to support them.

The Carboniferous was a wet time, and much land was covered by swamps. When the trees died, they were buried in these swamps, and gradually squeezed to form coal, as the younger layers piled up on top.

ETH-BIB-Carbonlandschaft-Dia 247-02297

The Carboniferous Earth, a vast land of swamps and forests, of primitive plants, which became the coal that fired the industrial revolution (Leo Wehrli [CC BY-SA 4.0 (], via Wikimedia Commons).

Ironically, making the Earth lush with trees reduced the greenhouse effect so much that it created an ice age. The Carboniferous was the last time the Earth had pole caps before the ice age we are in right now.

Coal is abundant all over the globe. Most of it occurs in Carboniferous rocks. The first geologists, out looking to find coal seams to dig, saw the pattern quickly: Coal occurred mainly in a certain interval in the rocks of the underground. They did not know the evolution story behind, but it was useful knowledge to find the fuel of the industrial revolution.

Of course, coal exists in younger rocks as well, because trees continue to grow in swamps to our day. On Spitsbergen, the Norwegian outpost high in the Arctic, the mines in Pyramiden dug for Carboniferous coal, but the coal in the mines in Longyearbyen and Barentsburg is much younger, from the Paleocene, around 60 million years old. It comes from a time when Spitsbergen was both further south, and the climate much warmer. But such coal come from forests and swamps that were local or regional. Never since the Carboniferous have such thick coal beds formed almost everywhere on Earth.

The map shows that British coal fields are concentrated in some distinct areas: The Midland Valley in Scotland, the south and north of Wales, and a broad band stretching from the northeastern Yorkshire coast, through the Midlands and wrapping the Peak District, and to around Birmingham. Nearly all the mines lie in narrow bands after each other, as if laid up in a row for the seven dwarfs to have one each.

Themain coal mining areas of the British Isles: The Midland Valley in Scotland, South and North wales, and the central England, straddling the Lake District. (Map from the Northern Mining Research Society,

To see the pattern of the geology of the UK, I strongly recommend the fantastic Geology of Britain viewer of the British Geological Survey!

How did the coal seams get this pattern? The story starts long before the coal seams themselves, in the Early Devonian, around 410 million years ago. Then, the now northwestern part of Europe clashed into Greenland and North America and made a mountain chain, which may have been as tall as the Himalayas. The Caledonian mountain chain got its name from the old name for Scotland, and the mountains stretched all the way from Spitsbergen in the north, through Norway, across the yet-to-open North Sea and Scotland. The mountains in Scotland and Norway are probably the last remnants of these mountains.

What goes up must come down. The Caledonian mountains collapsed under their own weight, and the collapse happened along large fault zones. One of these fault zones is the Highland Boundary fault, which runs along the north side of the Midland Valley. The Midland Valley is a graben, a trough which formed in between highs in the Caledonides. Midland Valley was first filled with sediments from erosion from the mountains, Then, Carboniferous sediments followed, along with volcanoes, and the coal towards the late Carboniferous. But, no coal deposited north or south of the Midland Valley because those areas remained high through the Carboniferous.

England was south of the Caledonides. Coal likely covered large areas of England at the end of the Carboniferous. But not as a wide blanket, because of our old friend, tectonics.

The Carboniferous was the time when the continents really started to assemble to the supercontinent Pangea, the “all Earth”, with nearly all land mass lumped together into one continent. The puzzle had many pieces, which assembled through at least one hundred and fifty million years, from the early Devonian until the mid Permian. Towards the end of the Carboniferous, 300 million years ago, several small continent pieces added to complete what is now southern Europe. These clashes crated a belt of mountains through Europe, from the southern part of England through Germany and further into eastern Europe. It is called the Variscan or Hercynian mountain belt, after old latin names for, respectively, an olde German tribe, and the Harz area.

The result was that England got a big kick in its rear part, which pushed up many small mountains. The coal was preserved only in the lower areas in between.

Still, it was more than enough to fuel the industrial revolution, and to heat Britain through the next two hundred years. It came a high prize. Children worked in the mines under terrible conditions. Not until 1842 did the Coal Mine Act prohibit underground labour for women, and for boys under 10. Towns got black of soot from factory chimneys. London regularly choked in smog, from the many coal stoves used to heat the houses of the city. The smog was a regular, unwelcome visitor in London until cleaner gas took over from the 1960s.

At the top of production in 1913, British mines (including Ireland) produced 287 million tons of coal. At the top of employment, in 1921, 1,25 million Britons worked in coal mining. Then, through the 20th century, gas, oil and nuclear replaced most of the coal in the UK. Today British coal mines produce around 8 million tons per year, and only two thousand people work in coal mining. The last underground mine closed in 2015, and only some open pits remain.

But still, we owe much of our wealth today to an invention evolution did long ago, when lignine made it possible for plants to make stems. And to how plants used it to suck out carbon from the atmosphere and bury it, almost at once in a geological time perspective.

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