A Journey into Scotland … Part 43
A Diversion into the History of Scottish Geology IV
There were many theories to explain why the fossil record of North West Scotland should more resemble North America than England. Scientists and theologians alike, stood side by side and, put forth explanations that allowed them to retain pre-existing beliefs. The idea of a land bridge linking Sutherland with Newfoundland was popular for a while; the Bible literalists adding the nice touch that it had been washed away by Noah’s flood. Unsurprisingly nobody put forward the idea that Scotland had once been part of the American continent and had somehow floated across the Atlantic Ocean to join up with England. Such an idea would have been preposterous.
A few more pieces were needed for this puzzle before even a genius was going to be able to see that there was a jigsaw at all let alone piece it together.
A jigsaw is a good metaphor though. It was something that had been noted from the time of Columbus. As late medieval cartographers started producing maps of the world, there were people looking over their shoulder saying things like “The west coast of Africa fits rather well into the east coast of South America”. It took a further four hundred and fifty years for someone to point out that there was a very good reason for this.
Just before Christmas in 1872 a ship, the HMS Challenger, set sail from Portsmouth on a voyage that would last four years and cover over 70,000 miles. The vessel was on loan from the British navy, had had many of her military features such as her guns removed and had been kitted out to make the most thorough survey of the world’s oceans ever carried out. An awful lot of the experiments involved lowering things over the side of the ship; either to take samples of the water or the seabed or to measure the depth. To this end the ship set sail with 291 kilometres of best Italian rope.
The whole expedition had been suggested by Charles Wyville Thompson of Edinburgh University and the scientific work of the ship was done under his supervision. It was one of the great fact-finding missions of the nineteenth century. One heck of a lot of science was to emerge from that ship. For our story we are mostly concerned with the mapping of the ocean floor. In the Pacific the ship was the first to realise the immense depth of the ocean and located both the Marianas Trench and what is still known today as the Challenger Deep. In the Atlantic it wasn’t just the depths that surprised the scientists but the fact that the ocean seemed so much less deep in the middle. They had located an unbelievably huge ridge that ran all the way down the centre of the Atlantic from the Arctic to the Antarctic. Though under the waves they realised that they had discovered the longest mountain range on the planet. What they didn’t realise is that they had discovered one of the key pieces in the geological jigsaw.
Meanwhile back in the mountains of Scotland we move into the twentieth century and an Englishman. Edward Bailey was part of the British Geological Survey’s work in Glencoe. We’ll overlook Bailey’s Englishness and concentrate on the work that he did in Glencoe. It should appeal to geologists and tourists alike. It certainly appeals to me. In his documentary Professor Iain Stewart spends a good deal of time establishing Bailey as a “gung-ho nutter” and it seems certain that he was a maverick. He did things his way and he did them full-bore. It was an attitude that saw him collect a double first from Cambridge, a heavy weight boxing championship and, later, medals of a different sort, and even greater honour, in the First World War where he lost an eye. He eventually succeeded to the chair of geology at Glasgow University and was director of the British Geological Survey from 1937 to 1945.
Professor Stewart likes him as someone who toughened himself up by taking daily plunges in ice cold lochs and getting his school friends to hit him in the face. I like him because he used to eat his lunch straight after his breakfast to avoid the need to carry it around with him all morning.
His discovery rather changes the complexion of Glencoe. Its geography and geology is stunning enough as it is. Its history was about to become a whole lot more explosive. He made two discoveries in the field and was able to step from these to an almighty conclusion that changed our view of the highlands and filled another piece in the geological jigsaw.
The team knew that the area contained a good deal of volcanic material but were not able to explain how it came to be there. There were two sorts of such rocks; large crystalled granite that had cooled slowly and small crystalled basalt that had cooled much more quickly. The mystery was how the rocks could be found side by side and in such quantities.
Bailey and his team carefully followed a large crack that led up a mountain out of the glen and mapped it carefully. When they brought their readings and measurements together they discovered that the crack formed a huge circle, eight kilometres across. They realised that what they were looking at was a giant volcano which had grown so huge that the cone had collapsed into itself releasing millions of tons of magma in one of the biggest explosions ever seen on earth. The huge circle mapped by Bailey was a new type of volcanic feature; a caldera. These occur when so much magma is erupted in a volcanic explosion that it empties the magma chamber and there is nothing to support the weight of the mountain above and this collapses into itself. 420 million years ago the west of Scotland was one of the most volcanic areas on earth and Glencoe was the biggest volcano of them all.
This discovery moved the science of studying volcanoes (vulcanology) forward but its full significance for geology was yet to be realised. It still needed a true genius to see the bigger picture (and here I mean it in its proper sense of being able to make intellectual and imaginative leaps that would be beyond most of us to see a pattern that led to an explanation). But, by now all the main pieces of the jigsaw had been assembled.
- James Hutton had observed that the creation and destruction of the earth was a continual process that went back further in time than had ever been conceived or imagined. He also put forward the idea that the force controlling this system was likely to be great heat from the centre of the earth.
- Lord Kelvin had established that the earth had an age that could be measured.
- Roderick Murchison made some errors (who didn’t) but established that the various ages of rocks could be measured accurately.
- Charles Lapworth had discovered that solid rock had been pushed sideways to form mountain ranges.
- Peach and Horne had found fossils in Scotland that matched fossils found 5000 miles away in Newfoundland and Greenland.
- Charles Wyville Thompson had discovered an unexplained ridge of mountains running down the middle of the Atlantic Ocean.
- Edward Bailey had revealed the incredible power inside the earth, and found that the highlands and islands of Scotland were full of volcanoes.
All of these discoveries were incredible leaps forward in the understanding of what made Scotland the place of such indescribable beauty. Individually they advanced learning by leaps and bounds. Collectively they were about to change both the academic world and our way of looking at the physical world. It is the idea that explains how whole continents can become divided by oceans, how volcanoes form and why earthquakes can be expected in some parts of the world and not in others. It was an idea that was to give us new expressions: continental drift, plate tectonics and the Pacific Ring of Fire. It was an idea so huge that it upset as many people from the scientific (and religious) communities as it satisfied. And the man who came up with it was a Scotsman.