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A Journey into Scotland in 1987 … Part 40

A Diversion into the History of Geology Part One

We owe Scotland a great deal. If Ireland has given English literature most of its great writers and certainly its greatest comic writers then Scotland has given us most of our great economic thinkers, many of our greatest engineers and an above capita contribution to arts and culture. There is one field, above all of these, where Scotland has led not just Britain but the entire world and that is in the understanding of that world. It was a scotsman who undertook the first scientific attempt to put an age on the planet and it was a scotsman whose theory was being undermined by this attempt and another scotsman who found the fatal flaw in the dating process to show that it was actually the earlier scotsman who had been on the right lines.

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Scotland has some of the most remarkable geology on the planet which may explain why it was in Scotland that the world gained a new science in the eighteenth and nineteenth centuries: the science of geology. Understanding the planet was all very easy before these people started looking more closely at the fabulous rock formations of the Highlands. Before this group of brilliant Caledonian thinkers came along, there was only really one geological textbook. It has become, in our own century the most blindly adhered to, and the most scathingly derided book of historical physics of all time. It was, The Bible.

It seemed to be remarkably accurate and had an explanation for why everything was how it was. It was because it had been created that way during six days of most diligent labour. At a stroke the known universe was put in place from something without form and void. And the bible students of the eighteenth century had gathered enough evidence, from this official planetary handbook,  to be able to confidently state that the world was created in less than a week, and were also able to give an exact date and time for when the work began.

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God rolled up his sleeves and set about making the world at 2 o’clock on Saturday the 22nd of October 4004 BC. He sat down to rest on the 29th. Everything that is became the way that it is during those six days. No need for geologists with theodolites and hammers to go marching off into the highlands to tell us differently.

But they went anyway. For some they undermined the laws of the universe and committed heresy. For others they were the very people who have given us more coherent theories and laws and a truer understanding of how the world came to be.

Much of the work was done in the stretch of Scotland I was about to cycle through. Of all the wondrous landscapes that Scotland had thrown at me during the first two weeks of my ride, I was about to enter the most wonderful. Welcome to Wester Ross and Sutherland. It simply doesn’t get better than this. It couldn’t.

I developed an interest in rocks and rock formations very early on. My elder brother had a collection of thumb and fist sized pieces of pink granite and a crystallised grey rock, that wasn’t quite as beautiful to look at. He’d collected them on days out in the north western highlands: from stream beds, from outcrops and from the beaches. Not surprisingly, he went on to become a geographer. I loved to look at them, to feel the hardness and even to strike the stones together and watch the sparks. These rocks seemed slightly dangerous to me. If I was a little more learned at the time, I might have been a little more entranced by their danger. They would have set a geiger counter ticking. Both the granite and the Lewisian Gneiss (for that was the grey rock) were (very mildly) radioactive.

Professor Iain Stewart Photo credit BBC

Professor Iain Stewart Photo credit BBC

A few years ago Professor Iain Stewart had half the population of the country tuning in to his history of Scottish geology at weekday teatimes. He has an engaging manner, a deep knowledge and infectious enthusiasm for his subject that you’d like every teacher to possess. For a few weeks, what had fascinated my brother and I, caught the imagination of the country. In this sense I think of it as landmark television. It was certainly landscape television.

In the first two programmes he took us deep into the remotest areas of this north west part of Scotland and introduced us to the men who looked at the mountains and couldn’t stop asking the  same question: how on earth did that get to be like that? Some were Christian believers and some were atheists. Some allowed science to rule and make discoveries. Some were held back by having a pre-conceived idea in their minds. These were not always the ones you’d expect them to be. God fearing James Hutton was able to move away from a literal reading of the bible to come up with a theory that completely undermined the accepted theological standpoint of his time.

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“Amazingly, for something conceived two hundred and fifty years ago, it is nearly all right. It is a big coherent, impressive idea; and his concept of the earth as a system – continually self-renewing – feels so modern.” (Iain Stewart)

Hutton was the first to realise that the process of erosion, that washed the soil from the fields of the family farm into drainage ditches and on into streams and rivers, would result in two things. One, the gradual sedimentary effect on the sea floor that would lead to the formation of new rocks. Two, that this seemingly would eventually lead to a completely barren landscape where all the fertile soil had been washed away. He noticed that despite millennia of erosion the landscape was still rather fertile. He had many accurate insights during his lifetime. One of these was that the creation of land and destruction of land go together and are not the result of some sudden and dramatic events in the biblical past, but are slow and imperceptible and are happening all the time and continue to happen. Hutton gave to modern science the concept of deep time. Before Hutton the earth was thousands of years old, after Hutton we knew that it was many millions.

In Hutton’s own words. “There was no vestige of a beginning and no prospect of an end.”

His second insight was that not all of the rocks in Scotland were formed by the sedimentary process. That many were (like the granite and the gneiss in my brother’s collection) formed by rocks becoming molten and then solidifying. Once he’d accepted that some rocks began life in a molten state the question for Hutton was why were they all so different?

Hutton, like many truly great thinkers, spent a lot of time studying and discussing outside his own field of interest. He was a friend of another great Scot, James Watt; the man who turned steam into an efficient form of power; and by doing so enabled the Industrial Revolution. By discussing ideas with Watt, Hutton came to be of the belief that the earth could also have a central core of heat that acted as an engine or driving force to changes in the landscape. He was right, but not many, including Lord Kelvin the great physicist, were prepared to believe he was right.

His time working among the crucibles and furnaces of Watt’s world also gave him the answer to how once molten rocks could have such great variety. He saw glass that had been melted and cooled rapidly and, almost by accident, he saw glass that had been melted and cooled very slowly. All such cooling leads to the formation of crystals but the rapidly cooled glass formed tiny crystals and was consequently transparent or translucent. The slowly cooling glass formed much larger crystals and was barely recognisable as glass at all. He concluded that molten rocks will have different properties according to how long they took to cool. This explained the great variations.

Photo Credit Bouncing Bertie

Photo Credit Bouncing Bertie

His third great insight was to recognise that, if there was indeed a molten core to the earth, then there would be places where the molten rock actually intrudes into pre-existing sedimentary rock: that it would squeeze itself into the gaps and the cracks. He left the workshops and study rooms of Edinburgh and did what everybody should do at some stage of their life. He went out into the glens of Scotland and had a very good look round. In Glen Lilt was the evidence he was looking for. He found pink granite, almost identical to that owned by my bother, that had squeezed itself, in its molten state, between the gaps of grey sandstone. 

It wasn’t enough to convince the great minds of those of his own age who already had the answer (the wrong one) but it proved enough to convince later geologists to take up their hammers and to go on to make further discoveries. Science is about passing on the batten. Hutton had run the first lap of this relay and run it well. He was the first to see the true history of the planet written in the Scottish landscape. The batten was dropped (largely by Lord Kelvin), and lay on the track for the best part of sixty years. But it was picked up again and tomorrow I’ll have a look at the work done by some more of the great Scotsmen who gave us our true understanding of the way the planet really came to be.