'Like a badly baked cake that sunk in the middle': New theory explains how Giant's Causeway formed

A new theory has been put forward to explain how the Giant's Causeway was formed.

The UNESCO World Heritage site gets its name from local folklore, which suggests the stones were put in place by the giant Finn McCool to cross the North Channel to Scotland.

However the widely-accepted scientific explanation is that a river valley was filled with lava that ponded to a greater depth than normal, which cooled and solidified into columns.

This theory has stood since 1940 - but it has now been questioned by Dr Mike Simms, curator of natural sciences at National Museums NI.

He has put forward the idea that if this lava-filled hollow was a valley it would have cut through old layers of lava beneath.

Dr Simms says he has identified layers of old lava on the shore either side of the Giant’s Causeway sloping inward where older layers have not eroded away.

He explained his theory with the analogy of a cake.

"Eroding a river valley is rather like cutting through a layer cake to reveal layers beneath the surface," continued Dr Simms.

"In my interpretation, what we actually see are layers of older rock sloping towards the causeway – more like a badly baked cake that has sunk in the middle.

“I believe the ground subsided as lava moved up and erupted at the surface. The lava filled the depression creating the conditions for the columns to form.

"This event likely took just a few days rather than the many thousands of years that would be needed for erosion to create a river valley."

The discovery has been acknowledged by the National Trust, which operates Giant’s Causeway.

Max Bryant, general manager at Giant’s Causeway and Carrick-a-Rede, said: “This new interpretation demonstrates that even at a site as well-known and well-studied as the Giant’s Causeway, there can always be new possibilities and perspectives waiting to be discovered.

"It highlights just how marvellous, magnificent and mysterious a geological formation we have here in Northern Ireland to share with the world."

Kathryn Thomson, Chief Executive of National Museums NI, added that she is "proud to support Mike’s findings".

She continued: "I think it’s wonderful he has showcased the expertise of our team and how important museums are."

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