The most famous example of columnar basalt – close-packed hexagonal columns of hardened Lava in a beautiful geometrical arrangement that suggests that some built them – is Giant’s Causeway in ciounty Antrim in Ireland. I’ve seen pictures, but we didn’t get that far north when we visited Ireland many years ago.
It became clear to me quite a while back that these were almost certainly examples of frozen Benard Cells in the original roiling lava, fractured into neat hexagonal columns by weathering and temperature cycling. the internet seems to agree.
I’ve known about the Irish example, but I’ve seen things that suggest that the formation may be much more widespread. The lion enclosure at Franklin Park Zoo in Boston is built to resemble a columnar basalt structure, so they are either suggesting that these are in equatorial Africa, or else the zoo designers just liked the image too much. There’s a housing development not far from where I live that has the name of the place enclosed in hexagonal basalt columns.
so I looked it up. Lo and behold, there are lots of examples, including one right here in Massachusetts (although a pretty long distance from the development). There certainly are examples in Central Africa, so maybe there is a place where lions sleep among the Giant’s columns.
With due respect to the Irish, I think the most famous example of this kind of geometric structure is Devil’s Tower in Wyoming; it was even prominently featured in *Close Encounters of the Third Kind* (and Paul, which is arguably the better movie). These are actually not uncommon structures although because of how prone they are to weathering (as water can enter in between the columns and the freeze, causing them to shear off) they erode relatively quickly compared to other types of igneous intrusions. They are spectacular and eerie-looking geological formations, to be sure.
We saw several examples of the basalt columns at Yellowstone when we visited there. They’re very impressive, and even when you know that they’re created by natural phenomenon, one’s brain still insists that they must be man-made.
I think recognition is partly a cultural thing, but I’ve never heard of Devil’s Tower, Looking at the picture, I don’t think it has anything like the weirdness of the Giants’ Causeway. Just another mountain.
So incredibly cool! Thank you for enlightening me today!
So many of the sites look like sorted and stacked the columns, or knocked them over like dominos.
My brain created a scene in the picture of the Tasmanian site. The reddish streaks (iron oxide?) made the columns look like a choir of brown-robed medieval monks.
I daresay most non-Irish have never heard of the Giants’ Causeway, either. And Devil’s Tower is perhaps significant in that you can see the extrusion well above ground level, not as “pavement” near the ground.
Nan Madol is a Micronesian ruined city built of basalt columns. They used the columns like other cultures used stacked logs. There are lots of photos online. My first exposure to it was through Cthulhu mythos stories, and I didn’t realize at first that it is a real place.
'Mongst the columns, the basalt columns, Cthulhu sleeps tonight…
And, to @Northern_Piper, Elmer is referring to Close Encounters of the Third Kind, in which Devil’s Tower played a significant role. At least here in the U.S., there were likely a lot of people, at one point, who only really knew of Devil’s Tower from that movie, but CE3K is now 44 years old, and likely doesn’t have the same cultural relevance today.
Here is another, less well-known, site about an hour’s drive from home in the northern Sierra Nevada in CA - Machado Postpile. I have yet to pay this area a visit, altho it will be sometime this hiking season, I hope!
I knew it well, but only from this movie. During my family’s move from WA to IN about 5 years ago, I was hoping for some sightseeing. Devil’s Tower didn’t make the cut, but I found that, if you look north at just the right time when cruising along the nearby interstate, you can see the top of the tower poking up beyond the intervening ridge. It is pretty far distant, 10 - 20 miles maybe, so it’s easy to miss.
'Mongst the columns, the basalt columns, the lions sleep tonight…
