Mystery of Giant’s Causeway formation solved with help from Iceland

13 Apr 2018

Giant’s Causeway, Northern Ireland. Image: Christopher Kane/Shutterstock

The Giant’s Causeway in Antrim, Northern Ireland, is one of the great natural wonders of the world, but it is only now that we know how it was formed.

Many of the tourists who flock to the island of Ireland each year go out of their way to visit the northern coast of Antrim to witness the geological marvel that is the Giant’s Causeway.

While the legend goes that Fionn mac Cumhaill – the mythical giant – built the towers of basalt as a bridge between Ireland and Scotland, scientists have spent years trying to replicate their formation in the lab, with no luck.

But now, according to The Guardian, a breakthrough has finally been achieved thanks to analysis of a basalt sample from the Eyjafjallajökull volcano in Iceland.

In a paper published to Nature Communications, a research team from the University of Liverpool described how, by obtaining samples from the Icelandic volcano – responsible for a similar basalt formation outside the town of Vik – they were able to replicate the structures.

The 20cm cylinders of basalt were held in place and blasted with heat reaching 1,000C until they began to melt to become lava, and were then subsequently cooled.

It was only when they reached a temperature of between 840C and 890C that the basalt magma fractured, suggesting that these temperatures were the conditions experienced at the Giant’s Causeway.

Now to go even bigger

“[This] is a question that has fascinated the world of geology for a very long time. We have been wanting to know whether the temperature of the lava that causes the fractures was hot, warm or cold,” said the paper’s lead author, Yan Lavallée.

“I have spent over a decade pondering how to address this question and construct the right experiment to find the answer to this question. Now, with this study, we have found that the answer is hot, but after it solidified.”

The next step for Lavallée’s research is to replicate it on a grander scale by using a large pool of magma to reproduce the basalt structures, but this will require a great deal more effort in making sure that the laboratory conditions are controlled.

Colm Gorey was a senior journalist with Silicon Republic