Meeting Report: Life on the rocks
Professor Stuart K. Monro OBE, DUniv, FRSE, Scientific Director of Dynamic Earth, was invited by Dumfriesshire and Galloway Natural History and Antiquarian Society to deliver the James Williams Memorial Lecture of 2013. Fittingly, in view of James' lifelong interest in Geology, the subject chosen was Life on the Rocks.
From the outset the huge audience was spellbound. Humour permeated the talk presented in a lucid, authoritative style and delivering a body of knowledge which demonstrated how the subject has changed dramatically over the years. David Attenborough, a man who inspires, motivates, excites and stimulates people about the natural world, was and is Professor Monro's role model.
James Hutton (1726–1797) is regarded as the father of modern Geology. He believed that "the present was the key to the past and that the past is the key to the future". Siccar Point near Cockburnspath is world famous as the most important site described by Hutton in formulating his ideas on the origin and age of the earth. It remains much as it was when Hutton visited in 1788. Vertical rocks are caused by squeezing of the horizontal ones and at this site Devonian red sandstone 400 million years old, washed by the sea, reveals strata of the structure of the rocks with Silurian sediments below.
Hutton was not a good communicator but Charles Lyell's Principles of Geology set out the observations made by Hutton. A copy was sent to Charles Darwin and shaped the way that biological thinking was going.
The mesosaurus, early aquatic relative of reptiles, is found in both Asia and Africa: this information was revealed when the ocean floors were examined and their secrets unlocked in their magnetic properties. This fact suggested that the two continents were once joined and provides some of the earliest proof of continental drift.
Plate Tectonics is one of the big ideas in science. In the Himalayas on the riverbed of the Kali Gandaki there is a rock and in it is an ammonite fossil from the sea, which has been thrown up thousands of metres by earthquake. Rocks behave like champagne and deliver pyroclastic flows such as wiped out Pompeii. Such happenings are still taking place: witness the devastating destruction in Christchurch, New Zealand in 2010; the eruption of Eyjafjallajökull glacier in Iceland also in 2010 which catapulted fine-grained ash into the air and grounded aircraft in Europe; the earthquake in S.W. Pakistan on 24th September 2013, to name but a few.
Remembering the statement that "the past is the key to the future", there is a sleeping giant, namely Yellowstone, which erupts every 600,000 years. Another eruption is overdue by 30 thousand years. The magma chamber's pressure is building up by 5 metres every year.
Continental drift continues almost imperceptibly. What does the future hold? At Gullfoss Waterfall in Iceland where America and Europe came together a bridge was built. Europe is drifting away from America at the rate our fingernails grow. The Atlantic is widening. Australia is moving northwards and will collide with S.E. Asia. In 250 million years time Scotland will be further north and cooler.
It is a dynamic earth, a small blue ball hanging in the infinity of space; but it is home, a home we are still learning about and need to know more about…
The talk ended with David Attenborough reciting the words of the Louis Armstrong song, "What a wonderful world!"