Sudbury, the Big Nickel, and BIFs
When I lived in Canada as a child we were always taking these long road trips to see the sights. Some of the places were more interesting that others. One that I remember from when I was about three or four was visiting Sudbury, Ontario. At the time I’m not sure I found it very interesting, but it definitely made an impression. One of the clearest memories is of the Big Nickel. The nickel is a monument which was created to symbolize the importance of nickel mining in the Sudbury area.
Perhaps we were visiting in the winter, but what I remember was a desolate hillside with almost no vegetation with this giant nickel on a pedestal. There were some other coins there too, but the Nickel was the main attraction. The surroundings were bleak and I wondered why anyone would come there. If you’d like to know more about what it looked like, go check out the work of photographer Edward Burtynsky.
This is the Nickel as I remember it. It turns out that it was only a couple of years old (maybe less) when I saw it as a child. It just celebrated its 45th anniversary this year after being refurbished in 2003 and mounted on a new pedestal. On the same trip we drove through a deserted town of boarded up houses. My father explained that this was where they had mined Uranium. Why would this be on anyone’s list of tourist attractions? Perhaps it explains things if I say that my father was a metallurgist…
There was an interesting paper in Geology recently about the Sudbury Basin. This is a giant crater that was formed when a giant meteorite hit the earth almost 2 billion years ago. It left a scar about 40 miles long, and was the source of the nickel.
The paper argues that this impact was responsible for the end of the banded iron formations. Banded iron formations are a rock formation which is found on ancient seabeds all over the world. They’re made of alternating layers where iron was and wasn’t exposed to oxygen. The theory is that the oxygen was being created by early photosynthetic algae. These layers could only form when the ocean waters didn’t contain much oxygen.
Slack & Cannon’s paper says that this impact created a tsunami which was so large that it mixed oxygen which had been building up in the atmosphere and surface waters deep into the ocean and stopped the formation of BIFs. They’re talking about a wave which was a kilometer tall near the impact site and a hundred meters tall several thousand miles away. A wave which stirred all of the world’s oceans right down to the bottom. That’d make a pretty great disaster movie, wouldn’t it?
The paper is behind a paywall, but you can find a pretty good summary here.