Origin of strange rocks in Ireland revealed

File photo.

Wednesday, October 21, 2015, 6:31 PM - The Giant's Causeway is a region containing about 40,000 interlocking rock columns. Located on the northeast coast of Northern Ireland, this spectacular stretch of land is the result of an ancient volcanic eruption. For centuries, scientists have been studying why the stones in the area fractured in such a peculiar way. Now, a team of physicists has found the answer.

German researchers have devised models to explain why hexagonal columns emerged from what was initially a rectangular pattern of cracks in cooling lava.

Logic would dictate the columns should be rectangular, but they aren't.

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The Giant's Causeway is believed to have developed some 55 million years ago. It was declared a world heritage site in 1986, and a National Nature Reserve a few months later.

Readers of the British publication Radio Times declared it to be the fourth-greatest natural wonder of the UK in a 2005 survey.

For their study, researchers used 3D models to analyze the how the lava behaved when it was hot and when it cooled.

They discovered the inner parts cooled faster than the outer parts. This lead to shrinkage and crack formation and caused the columns to form at 90-degree angles.

As lava continued to cool, more shrinkage occurred. The cracks made their way down to the lava below which was still solidifying, causing the cracks to grow larger.

During this process the release of energy caused the angle to shift to 120-degrees, which is the angle degree found in hexagonal structures.

The shape maintained its structure as the lava cooled. This happened thousands of time, creating the columns that are now referred to as the Giant's Causeway.

A complete paper on the finds was published earlier this month in Physical Review Letters.