“EXPLORATION OF THE ROCKS OF SICCAR POINT & HOW JAMES HUTTON’S OBSERVATIONS CHANGED THINKING ABOUT THE AGE OF THE EARTH.”
A Presentation by Elizabeth Devon
Elizabeth started the talk by looking at photos of the rocks of Siccar Point as James Hutton saw them.
She explained that from his observations of the movement of pebbles, sand and mud in rivers, he saw that the rocks here were all made of sediments, but he noticed that there were two distinct varieties. The lower rock appeared to have been moved into a vertical position and the upper rock was utterly different, with the base of it containing pebbles of the lower stone. Society members were encouraged to think like James Hutton and to try to work out what had happened.
In the second section of the talk, there was a brief biography of James Hutton’s life and an explanation of the Scottish Enlightenment, a time of tremendous discovery and innovation in all fields, from science to the arts.
Thirdly, Hutton’s conclusions about what he thought had happened at Siccar Point were explained.
He thought the Earth worked in a cyclical way like the orbits of planets or blood circulation and he thought there were many, many cycles. He thought the Earth behaved like a dynamic heat engine so causing rocks to be tilted. His main conclusion, though, was that the Earth was millions and millions of years old and not 6,000 years as was believed at the time. He said, “We find no vestige of a beginning, no prospect of an end”.
Lastly, Elizabeth gave the up-to-date geological explanation for Siccar Point, the lower rocks being c.435 million years old and the upper c.370 million years old, so leaving a time gap, or unconformity, of about 65 million years. Here she demonstrated deep time with the ‘arm’ analogy to much amusement!
7th June 2023