A Journey into Scotland in 1987 … Part 41
Up here in Sutherland the earth feels ancient. I’m cycling through the oldest landscape in Great Britain and between some of the oldest rocks on the surface of the earth. Just how old was a very big question in the nineteenth and twentieth centuries. It’s a question we think we may well have answered in the twenty first.
According to theologists, the earth was 4004 years plus the year you are measuring from. If it is 1750 then this will mean the earth is 5754 years old. Brilliant if you take a literal view of the bible (and this Christian believer’s belief is based on things being believable) but problematic if you are wondering how that fits in with 540 million year old fossils. Lord Kelvin was the first to make a serious attempt to work out how old the earth was and he did it more with the intention of establishing that the planet had an age rather than to establish just exactly what that age was. He was reacting to the idea put forward by James Hutton that the processes of the earth were on-going and had no obvious point of beginning and no foreseeable point of termination. In its way it is a re-affirmation of the position of ancient Greek philosopher Heroclitus of Ephesus who believed that nothing actually exists in itself but only as a constantly changing form on the way to becoming something else. In this view there is nothing other than flux. No beginning or end; just constant change. He famously expressed this idea by saying that no man can jump into the same river twice. (Geologists have more experience of testing this idea than most.)
Hutton’s way of expressing it was to say that he saw “no vestige of a beginning and no prospect of an end”. Kelvin thought this was nonsensical and set out to measure the age of the earth so he could say that there most certainly was a beginning.
According to Lord Kelvin, the earth was molten when it first formed If you can time how long a measured amount of molten rock takes to cool to earth temperature, then you can tell how old the earth is. He came up with the answer that the earth was between 20 and 40 million years old. This displeased everybody:
- it was far too old for the creationists. There would have to be an awful lot more begetting in the gospels to link Jesus’ lineage to Abraham.
- It was far too young for the Darwinists. Evolution couldn’t have performed its task in so short a time
- his calculations were based on the entire earth cooling which would have ruled out Hutton’s other idea that the centre of the earth remains red hot and that this heat powers many of the changes in the earth’s geology.
We now know that the earth is 4.6 billion years old and that some of the rocks in north west Scotland have been around for more than two thirds of that span. The rock known as Lewisian Gneiss has been accurately measured as being over 3129 million years old. We know these figures are accurate because we have been told so by the most reliable source there is: by the rocks themselves. (The secret lies in discovering radioactivity and knowing that it is a natural and not a man made phenomenon.)
A third great Scottish scientist enters the scene in the middle of the nineteenth century. Roderich Murchison, like many scientists at the time, was a wealthy man with time on his hands looking for something to do. Either his wife or Sir Humphrey Davy should be credited with suggesting that he gave up fox-hunting and take up geology. The first half of his career was very successful and he was part of the group of thinkers (which included Charles Lyell and Charles Darwin) who were able to classify rocks according to their age. Having been knighted for his work he then went to the north of Scotland where he used all his influence, position , authority and academic record to establish an incorrect idea. Like Kelvin’s inaccurate and wrongly premised measuring of the age of the earth, this mistake held up geological research for decades. Put simply he asserted that the oldest rocks will be found at the bottom and any rocks on top of these must therefore be younger. It makes sense superficially but it denies other reasons why things end up on top.
Murchison’s geological map of northern Scotland followed his own findings and theory to say that the oldest rocks are to be found furthest west and that the rocks become progressively younger as you cross the country eastbound.
The false finding in Murchson’s work was uncovered by a great enthusiast. The only major figure in this story who wasn’t a scot. Charles Lapworth was English, but lived in Scotland, married a Scottish wife and did much of his most important work on the mountains around Loch Eriboll in the north of Sutherland. Diligent and meticulous fieldwork found site after site where relatively young rock was found beneath rock that was by all standards of measurement (except Murchison’s) much older. He needed an explanation and he came up with one; a good one; one that worked then and which works now. An explanation, in short, that allowed further discoveries to be made. He put forward the idea that an enormous sideways force was acting on the rocks which pushed them. He devised a simple experiment to see what would happen. Inside a glass case he laid down layers of different coloured sands. Once he had a good number of these layers he slowly turned a wheel that moved the end wall of the case inwards. The sands were pushed further into the box and as they moved they began to form ripples and then wave patterns and eventually the lower layers were to be found going up and over the top of the layers that had originally been higher. His sands resembled, almost exactly, the patterns of rock layers he had found in the field. He had not only explained how older rocks can end upon top of younger rocks but had effectively explained the process of mountain building.
It is interesting that it was an Englishman who explained how Scottish mountains were formed as it was England that played a major part in actually forming those mountains. Scotland provided the layers of sand/rocks; England provided a good part of the sideways force that gave us the Grampians, the Torridons, the Southern uplands; Ben More, Foinhaven and even Ben Nevis itself. But that part of the story is still to come. There remain a few pieces of the puzzle to put on the table.
Murchison was decidedly displeased. Two scientists, John Horne and Ben Peach, were sent to Sutherland to find evidence to disprove Lapworth or at least to undermine his theory. Scientists regard themselves as dealers with the truth but there are a remarkable number of instances where they put their personal reputations and (dare I say it) beliefs, before the scientific facts. Scientists tend to define themselves according to the work of the best of their type and not by the work of those whose efforts have held back the discovery of knowledge. At the same time scientists have developed something of a habit of condemning faith and religion on the grounds that some people follow paths of religion that are wrong, deluded or just plain evil. If we judge scientists by the weaker members of the sect then we have a pretty shabby bunch. But to judge any of us by our failings would leave few of us with much glory. Fortunately Horne and Peach were not the shabby sort.
They were sent to disprove a theory and came back having fairly conclusively provided the evidence for the theory to stand, and for science to be able to advance. What is more, they provided evidence to say that if there is a natural union for Scotland, it might make more sense for the country to form links with Canada or the USA rather than with England. They went into Smoo Cave (a place I will visit myself on this cycle journey) and came out with a good collection of trilobites. Nothing strange there. Trilobites had been found all over the British Isles. They are the fossilised remains of marine creatures that swam in warm shallow waters 500 million years ago.
The trilobites that had been found in England were almost identical to the ones that had been found throughout mainland Europe. Those that were found by Horne and Peach were almost identical to trilobites found in Greenland, Newfoundland and north eastern parts of the North American continent. Something didn’t make sense.