(Image: Lundgre/Wild Wonders of Europe/Naturepl.com)
Diving into a yawning underwater cavern is scary enough, even when the rock walls aren’t shifting. Luckily, this intrepid diver knows that they aren’t closing in. For that he can thank a seminal paper published 50 years ago today.
The crack is actually the tectonic boundary between the Eurasian and the North American plates under the surface of Thingvellir Lake in Iceland. It’s a stunning illustration of how the movement of magma in the Earth’s mantle pushes continental plates around on the surface – the subject of the paper by Drummond Matthews and his PhD student Frederick Vine, both of the University of Cambridge.
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Matthews and Vine looked at how the Earth’s changing magnetic field was locked into extruding lava and spread in stripes across the sea floor like pulling taffy. Their work showed that the sea floor was spreading.
This evidence, concurrently discovered by Lawrence Morley of the University of Toronto in Canada, overthrew the idea of a static Earth and awakened our understanding of our living, moving planet.
Volcanic island countries like Iceland owe their existence to such tectonic activity, and plate movements underlie major events in human societies. The constant recycling of the Earth’s crust provides us with a stable climate, mineral and oil deposits and oceans with a life-sustaining balance of chemicals. It even gives evolution a kick every few hundred million years. However, the origin of the Earth’s churning crust remains a mystery, with some even proposing that a comet kick-started the flow.
