Basalt columns

Giant's Causeway

A plane of columns

The Giant's Causeway is an area of 40,000 tightly packed basalt columns resulting from a volcanic eruption 60 million years ago. It is located along the north-east coast of Ireland about 3kms north of the town of Bushmills in County Antrim, Northern Ireland. It was declared a World Heritage Site in 1986, and a National Nature Reserve in 1987 (by the Department of the Environment for Northern Ireland).

The tops of the columns form stepping stones that lead from the cliff foot and disappear under the sea. Most of the columns are hexagonal, however there are some with four, five, seven and eight sides. The tallest are about 12 metres high, and the solidified lava in the cliffs is 28 metres thick in places.

Formation

While recent scientific research suggests the columns were formed as a natural consequence of lava cooling,² legend has it that the giant Finn MacCumhaill (Finn McCool) built the causeway to walk to Scotland to fight his Scottish equivalent Benandonner. One version of the legend tells that Finn McCool fell asleep before he got to Scotland so when Benandonner came looking for him, Finn's wife Oonagh laid a blanket over Finn and pretended he was actually Finn's baby son. Benandonner worried about how big Finn would be and ran back to Scotland, destroying the causeway and leaving a boot behind in his rush. Other versions of the legend name the Scottish Giant 'Fingal'. At the Scottish side of the causeway at Staffa there is reference to this in the naming of Fingal's Cave,³ although this has also been said to derive its name from Fingal, a legendary 3rd century Scottish king.

Other examples

Although the basaltic columns of the Giant's Causeway are impressive, and possibly the finest example of their type, they are not truly unique. Similar - if less impressive - structures exist in several parts of the world, including at the Cyclopean Isles near Sicily, Devils Postpile National Monument in California, Devils Tower National Monument in Wyoming, and the "Organ Pipes" formation in Dunedin, New Zealand.

See also

• Geology of the United Kingdom
• UK topics

External links

• Official Causeway Guide

References

• Note 3:
• Note 2: Jagla, E. A., Rojo, A. G. Sequential fragmentation: the origin of columnar quasihexagonal patterns. Physical Review E, 65, 026203, (2002) (webpage)