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On the Road
We get the opportunity to visit some really beautiful places as we go round the communities of the Highlands.
As part of National Science and Engineering Week, Bill Graham and Maarten de Vries headed west to Ardnamurchan, to take a package of astronomy activities to the pupils of Kilchoan and Strontian Primary Schools.
An intrepid vulcanogist stands on the rim of the Ardnamurchan volcano
There was also time to see some spectacular landscape – in particular the ancient volcanic crater near Achnaha.
Geologists call it a caldera – the remnants of a volcano that was created 60 milliion years ago. What caused it was the pulling apart of two great continental plates that form part of the Earth's crust.
These are the plates that today form North America and Europe. They were once joined, but then they started to move apart, with the space that gradually opened up between them becoming the Atlantic Ocean.
The enormously massive continental plates float on the liquid mantle that lies beneath them. Currents within the mantle create slow movements of the plates above.
The movements are very slow – little more in a year than the growth of your fingernails. But over millions of years these little amounts build up, and the resulting forces can force continents together – or pull them apart.
It was a pulling apart that happened 60 million years ago, and that weakened parts of the areas close to the separation zone – amongst them the Ardnamurchan peninsula.
So hot lava from deep with the Earth poured out of the volcano. And when the eruption was over, the chamber of the volcano was empty. That empty chamber is the inside of the huge crater we see today.
Outside it is a narrow, steep-sided ring-dyke formed of the lava. There were several huge eruptions, and so there are several rings on the landscape.