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NatureSpeak Articles

Basalt is lit!

From wild lava landscapes to exotic textures, high-tech clothes to skis, basalt is an understated rock star that can even help fight climate change.

Spectacular basaltic eruption of Kilauea Volcano, Hawaii as new basalt wells up into the crater with alien looking webcams looking on. (USGS photo taken by L. Gallant.)

Basalt can be seen all around Whistler, erupted from local volcanos like Mount Cayley and Garibaldi, it is also used in landscaping and an eclectic collection of sculptures including, the world’s biggest pine cone and the giant Inunnguaq at Whistler gate.  There is even a great little restaurant, Basalt, on the stroll.  That said, I’m pretty sure many of you hardly give basalt much thought. But maybe you should, because this grey beautifully understated dense lava rock is in fact, a rock star.

To start off, it is the most common rock on earth, covering 60 per cent of the Earth’s surface. It underlies all the world’s oceans, forms massive basalt plateaus on every continent and the world’s largest volcano, Mauna Loa in Hawaii. Basalt is also found on the Moon, Mercury, Venus and Mars. 

Much of the earth’s basalt is formed at plate boundaries, where two plates move apart and new lava wells up and fills the space.  When these iron-rich rocks cool they capture the earth's magnetism and when geophysicists carried out the first ocean floor magnetism surveys off the coast of Vancouver Island, they were amazed to discover the earth’s magnetic poles had flipped periodically throughout geological time.  These “magnetic reversals” are often presented as black and white “zebra stripes” around all the world's oceans.

In 1963, Fred Vine, and Drummond Matthews of Cambridge University identified magnetic reversals on the basaltic seabed offshore Vancouver Island producing incredible black and white maps which looked like zebra patterns. Image by Vine and Matthews 1963 Nature article

Basalts often form vertical hexagonal columns as they cool and shrink producing dramatic landscapes like The Giant's Causeway in Ireland.  Here in southern B.C., our columns are quite unusual, they are not always vertical because some of our volcanoes erupted into a “Fire and Ice” environment, where hot molten lava came into contact with Ice Age glaciers, producing wild and wonderful lava columns in all sorts of wacky configurations.

Depending on how it forms, basalt can look quite exotic, sometimes gas bubbles, called “vesicles" are preserved in the rock producing an aerated bubbly texture like honeycomb candy.  Often these bubbles are filled with white minerals called “amygdales” named after the Latin word for almonds.  If there are lots of bubbles, basalt can look like a red-brown “cinder” called “scoria”, used as fire-pit rocks.  Researchers at the University of California, Berkeley, who studied the distribution of bubbles in basalt found that Guinness stout is a good analogue for gas released in lava flows. I have studied this phenomenon many times at the Dublin Gate pub. Sometimes basalt can have larger white crystals forming beautiful radiating clusters called “flower stone”, or randomly oriented clusters known as “Chinese writing stone.” 

Image by Stephen Carney

Basalt fibres have some incredible properties and are three times stronger than steel.  They have been used as an eco-friendly building material to make things like rebar and insulation, and in recent years to make hi-tech fabric for outdoor clothing and even skis and boards.

One last thing basalt is good for, recent research at UVic and the University of Calgary suggests that because of its worldwide distribution and mineral composition, gigatons of the greenhouse gas carbon dioxide could be stored in basalts, maybe even enough to bring down global atmospheric concentrations. One of these days basalt might even end up helping to save our planet.  

As I said, basalt is lit!

Written by: Stephen Carney


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