Geology of the channel tunnel

The Channel Tunnel carefully follows a chalk layer and avoids ancient waterfall plunge pools. Thousands of years ago, there was a land bridge, but now there is a train.

Earlier this week I found myself under the sea again. I’ve been taking the Eurostar any time I need to be in The Netherlands or France or Belgium. It’s not that much more expensive than a plane if you book ahead and it’s so much less hassle.

When you’re in the train, the tunnel feels like any other tunnel. But the little display on the screen above the aisle likes to remind you that you are, in fact, under the sea floor. There is a whole body of water above you, much bigger than a river.

Of course, building it wasn’t easy either. It won awards for its engineering, but there was also a great deal of geology involved. The tunnel follows a gently winding path so that it stays mostly within a layer of chalk where it was easy to dig.

Channel tunnel geology, from Wikipedia

When I looked up more about it, I learned that scientists discovered a few years ago that the route of the Channel Tunnel, and the geology of the Channel in general, was also influenced by ancient waterfalls. (More on that below the links).

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Interesting Links

Every two weeks Mixture brings you a mix of links that all have something to do with science, but also with other things.

• How to use Renaissance paintings to improve the farming of tomorrow. From the Smithsonion “There’s More To That” Podcast

• 66-million-year-old fossilized vomit found in Denmark. New York Times (gift link)

• The weird psychology of airports. The Conversation

• The subtle ways that science writing erases human exceptionalism. Mind Matters

• Music is becoming less complex over time, and we don't really know why. IFLScience

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Ancient waterfalls and the formation of the Channel

In 2017, researchers at Imperial College London shared that they had found out a bit more about the way that Britain separated from mainland Europe.