Nature Rocks! The Great Giant’s Causeway!
Nature, an all time Rock star! Lets delve into this geological wonder with the fable of fiery giants and the concept of columnar jointing.
At the time when MARVELous fables make us go crazy, let me take you to the world of giants’ geological marvels. If you are a little observant about the wondrous nature around you, I am sure there must be times where you must have gaped in awe, spellbound and believed in magic, miracle or some superior power or whatever.
Here it is to you, the astounding view of the Great Giant’s causeway of county Antrim in Northern Ireland, with some 40,000 interlocking hexagonal shaped basalt columns ranging from 12 m high to well below the Antrim soil.
No wonder people wonder, it to be of some superhero from Asgard, or in this case the giant’s work. There is a very interesting Irish mythology suggesting the formation of this UNESCO world heritage site.
The fable of fiery giants
Here comes Finn McCool representing team northern Ireland. Next comes his sheer rival Benandonnar from across the channel representing team Scotland. Yeah! Greater rivalry between giant neighbors!
Benandonnar: “You don’t know how lucky you are. If I were a strong swimmer, I would come over and give you a thorough thrashing!”
Finn Mc Cool: “Here it is to you..bite the dirt and die” and thus he scooped a mound of dirt and threw it at Benandonnar, challenging him to a fight.
He threw some more of these hexagonal blocks and created a causeway to face his enemy. But to his shock, he found that the Scottish giant was considerably bigger than him. So, he made a hasty retreat, but his rival was already following him. The petrified McCool was saved by the sharp intellect of his wife, who asked McCool to act as her child sleeping in the crib. When Benandonnar arrived, she referred McCool as her baby and that her husband went out. Now, it’s time for Benandonnar to run back. He was imagining the size of the father considering the baby’s size. The myth goes on like that…
The dirt scooped up by McCool is believed to have created the crater for Northern Ireland’s largest lake, Lough Neagh, and in falling into the sea, the Isle of Man. Fanciful names are given to different formations like the wishing chair, giant’s boot(which McCool left while retreating in haste), giant’s organ, the chimney top and so on.
So, what does the Geo folks has to say is:
The region is originally composed of chalk, which later got exposed to constant volcanic eruptions. The lava thus formed, intrudes the chalky landscape and gets cooled displaying variety of columns, with a strati-graphic pattern. Here comes the concept of columnar jointing, which are most common in basaltic structures.
When lava cools, the contraction takes place. When this contraction occurs at the centers which are equally spaced, hexagonal fracture patterns are observed. Fracture patterns that form at cooling surfaces will tend to propagate down the lava as it cools, forming long geometric columns. When the uniformity in cooling varies, 5- sided, 7-sided or other patterns are also formed. The formation of columns is particularly enhanced by water. Especially in river valleys, two-tiered sets of columns can develop, which are known as entablature(at the top) and colonnade(at the base).
This kind of columnar jointing is found in other parts of the world too, like the famous Devil’s tower in Wyoming, Devil’s Postpile in California; In India, such columnar jointing can be found well developed on the Karnataka coast in the St Mary’s island also called the coconut island, near Udupi.
It displays a majestic array of multi-faced columns evolved due to vast outpouring of hot molten basaltic lava of the Deccan trap, some 60 million years ago in the Cretaceous-Eocene times.
Comment if you have ever wondered over such marvels. For instance, even the hexagonal mud cracks or the pattern of beehives. Strangely, I am currently pondering over Christaller, who chose a hexagonal pattern of distribution in his central place theory.
