Earth has many spectacular geological structures. One of them is a basalt column. A basalt column is a pillar of rock formed from hardened lava in the aftermath of a volcanic eruption.
A basalt column takes thousands of years, sometimes millions, to form. This article describes the process of lava turning to basalt columns. It also explores various types of basalt columns around the world.
Related Read: Hottest Places in the World.
How are basalt columns formed?
How does Earth form an incredulous basalt column? We know the lava turns into basalt, but how does lava flow form perfect hexagons and other shapes of columnar basalt?
As a volcano erupts, it spreads lava and other volcanic materials to its surrounding area. The rapid cooling of the lava flow created many shapes of basalt rocks. As a lava flow cools down, its surface shrinks and contracts.
The contracting also causes fractures that move inward towards the center, creating various bits of hexagonal columns. An even basalt column forms when the lava flow is smooth.
The formation starts at the top of the lava, the part that cools the fastest. The middle and lower parts start cooling and follow the shape from the top, forming a cylinder. This extremely tall basalt column forms from the top to the bottom of the volcanic material.
Uneven and irregularly shaped columnar basalt forms when the volcanic materials are not smooth. The term used to refer to a hexagonal column is colonnade. Entablature refers to an irregular basalt column.
A 2018 study shows that basalt columns possibly form at temperatures between 1544℃ and 1634℃ degrees. The University of Liverpool conducted a study that copied the basalt’s formation and discovered that fracturing occurs between 194 and 284 degrees Fahrenheit. These are temperatures below the point where lava hardens into rocks1.
10 Basalt Formations Around The World
1. Takachiho Gorge (Japan)
The basalt columns formed from the lava flow from volcanic eruptions near Mount Aso over 100,000 years ago. These beautiful basalt columns formed in Takachiho, Japan. Takachiho Gorge basalts are graced with beautiful waterfalls, attracting tons of visitors.
The Gokase River flows through the rock walls at about 3m at the narrowest point. The blue-green waters around the columns are clear and pristine, with the waterfalls as high as 55.8 feet (17 meters). You can go sightseeing at the Takachiho Gorge because Japan protects the area as a National Scenic Spot and Natural Monument in Japan.
2. Giant's Causeway (Ireland)
The Giant's Causeway is an incredible landmark of 40,000 basalt columns that inspired legends and folklore in Ireland. Legend has it that a giant, Finn MacCool, created the Giant Causeway while crossing for a confrontation with his rival.
However, science has a more suitable explanation for this spectacular geology. The basalt columns formed from volcanic lava on the north coast of Northern Ireland. As the lava cooled, it formed hardened hexagonal and columnar structures.
These columns form the border of Northern Ireland, and some parts of the basalt columns extend into the waters below. It is one of the world's most popular basalt columns and a geographic attraction.
3. Devils Postpile National Monument (USA)
According to the National Park Service, a presidential proclamation declared the Devils Postpile Columns as a National Monument in 1911. It was to protect and preserve the basalt columns, the 101-foot rainbow rainfalls, and the mountain scenery.
The basalt columns used to be a part of Yosemite National Park in California, but the discovery of gold near Mammoth Lakes changed the boundaries in 1905. Devils Postpile became at risk because of a proposal to blast the rocks to build a hydroelectric dam.
It prompted activists in California to persuade the President, William Howard Taft, to protect the area as a National Monument. A basalt column in Devils Postpile has an average height of 3.5 feet, and many columns are about 60 feet long.
The lava didn't cool evenly, so the columns weren't hexagonal. Instead, they have polygonal cross-sections. The uneven cooling makes the Devils Postpile National Monument one of the top geological wonders of the world.
4. Basaltic Prisms of Santa María Regla (Mexico)
Basaltic Prisms of Santa María Regla are columnar jointing rocks located in Hidalgo, Mexico. These rock prisms form when the lava flow cools and solidifies, causing the rock formation to contract and crack into hexagons.
These Basaltic Prisms are well-known for their heights. Some areas of the cliff reach 98 feet. The waterfalls around the basalt column add to its natural beauty, making it a sight to behold.
The formation of the basalt columns took millions of years, a series of volcanic eruptions, and other stages of geological processes. The gradual cooling and contraction of the lava flow created basalt columnar jointing. Also, the presence of the waterfalls contributes to the formation of narrow channels and pools.
5. The Basalt Columns of Svartifoss (Iceland)
The basalt cliffs of Svartifoss are as enormous as the ones mentioned previously. The columns are about 65.6 feet (20 meters) tall, with water cascading over it. Icelandic people call the waterfall Black Waterfall or Black Falls. The basalt columns of Svartifoss are colorful, while some have black hues.
The basalt cliffs are nature’s beautiful work of art. You will find Svartifoss in southern Iceland's Vatnajökull National Park. Nature’s greenery surrounds the entirety of the basalt rock formation. The basalt rock inspired human art, like the architectural work of the National Theatre in Reykjavik.
In Svartifoss’ beauty, visitors do not swim in its waters because they could harm themselves. Some basalt cracked off the cliff, creating a sharp surface under the water. Swimming around sharp basalt stones could cause severe injuries.
6. Organ Pipes (Australia)
These basalt columns got their name because they resemble the pipes of an organ. They are the world’s largest and oldest basalt columns. Organ Pipes basalt stretches from the edge of Melbourne to the western border of Victoria. That distance is about 217.5 miles (350 kilometers).
The Keilor Plains and the Jacksons Creek surround the Organ Pipes. The Keilor Plains are one of the largest lava flow deposits in the world. Many sedimentary rocks and fossils also date back to millions of years ago.
To explore the basalt columns, walk a steep hill through the Rosette Rock and the Tessellated Pavement. The Rosette Rock resembles a giant wheel, while the Tessellated Pavement is a mosaic-like basalt outcrop.
7. Cape Raoul (Australia)
Cape Raoul is located in the southern part of the Tasman Peninsula, accessible via Port Arthur at the end of Stormlea Road. The basalt columns form the coastline of the Penisula. It takes about 5 hours of walking to get to the cape.
Shrubby greens and wildlife are on each basalt column formed by centuries of lava flow. Weather conditions and erosion from the sea also contributed to its uneven aesthetic.
8. Cape Stolbchaty (Russia)
Some claim that the Cape Stolbchaty is similar to the columns of Giant’s Causeways. Cape Stolbchaty is located on the western shore of Kunashir Island and the southern part of Kuril Islands, Sakhalin Oblast, Russia.
The basalt column formed because of the Tyatya volcano eruption millions of years ago. The lava flow created a pristine expanse of disc rocks. The cooling process of the lava created pentagonal and hexagonal columns.
Years of erosion chipped at the gigantic rock, forming a cliff almost 164 feet (50 meters) high with little basalt rocks. It is a unique, natural geometric arrangement. There are smaller pentagons inside larger pentagons.
9. Rochester Falls (Mauritius)
Rochester Falls is south of Mauritius, Souillac. It is a combination of water, kush grace, and basalt columns. It is one of the major tourist areas in Mauritius. The basalt column is not large but has a breathtaking view, standing 32.8 feet (10 meters) high. Water falls from the cliff into the Savanne River below the basalt rock.
10. Hexagon Pool (Israel)
The Hexagon Pool, a natural wonder nestled within Yehudiya Forest Nature Reserve in Israel's central Golan Heights, owes its name to the unique six-sided basalt columns framing it. These angular formations, standing at a height of around 16 feet (4.9 meters), result from waterfalls forging the pool. Each column is roughly 1 to 1.3 feet (0.3 to 0.4 meters) in diameter.
Other Basalt Formation Worldwide
- Fingal's Cave, Scotland
- Garni Gorge, Armenia
- S-shaped Columnar Basalt, High Island Reservoir, Hong Kong
- Stuðlagil Canyon, Iceland
- Columnar basalt at Froðba, Faroe Islands
- Akun Island Columnar Basalt, Alaska, United States
- Prismas Basalticos in Huasca de Ocampo, Hidalgo, Mexico
- Devil’s Tower, Wyoming, United States
The basalt column is part of the numerous geological formations and structures in many places on Earth. The cooling of the exposed surface of lava slowly creates the most beautiful columns from Russia to the USA. What basalt formation do you want to visit? Spend time in nature by hiking through nature’s wonders.
Lamur, A., Lavallée, Y., Iddon, F., Hornby, A., Kendrick, J. E., Von Aulock, F. W., & Wadsworth, F. B. (2018). Disclosing the temperature of columnar jointing in lavas. Nature Communications.