This week, we’ve been uploading clips from Richard Thomas’ film ‘Dan McKenzie and friends’, which looks at the early history of the theory of plate tectonics.
It’s easy to forget that plate tectonics, an idea we’re all familiar with at least on a basic level, isn’t all that old. It wasn’t until the 1960s that the theory as we know it today began to come together, thanks to the scientists featured in the film, as well as others.
Contintental drift, on the other hand, has been around for a surprisingly long time. Way back in 1587 the Flemish cartographer Abraham Ortelius wrote in Thesaurus Geographicus that the Americas were
“torn away from Europe and Africa…by earthquakes and floods”
“the vestiges of the rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three [continents]”.
Researching the early history of continental drift often brings up Ortelius’ name but, surprisingly, another scientist who was on to the idea years before a mechanism was established is rarely mentioned.
In his brilliant 1842 monograph on the structure of coral reefs, Charles Darwin proposes, among other things, a theory for how coral atolls are formed. His hypothesis that the circular reefs are formed by coral forming on a volcanic island, then growing upwards as the island subsides beneath it, was widely accepted but not proven definitely until the 1950s.
Outlining the theory, he writes;
“Do the areas which have subsided, as indicated by the presence of atolls and barrier-reefs, and the areas which have remained stationary or have been upraised, as shown by fringing-reefs, bear any determinate relation to each other; and are the dimensions of these areas such as harmonize with the greatness of the subterranean changes, which, it must be supposed, have lately taken place beneath them? Is there any connection between the movements thus indicated, and recent volcanic action?”
“it may, I think, be considered as almost established, that volcanos are often (not necessarily always) present in those areas where the subterranean motive power has lately forced, or is now forcing outwards the crust of the earth, but that they are invariably absent in those, where the surface has lately subsided or is still subsiding”
He is clearly onto the fact that there is some sort of ‘motive force’ under the surface which is driving these changes.
Here, as with inheritance, Darwin suffered from being too far ahead of his time, hypothesising ideas which he needed 21st century tools to prove. He wasn’t the only one – by the time Alfred Wegener presented the theory of continental drift to the German Geological Society in 1912, he was crediting several others with having proposed similar ideas. But the lack of physical evidence for the theory meant it was generally met with skepticism.
Even after Fred Vine and Drummond Matthews presented physical evidence that continents drifted in 1963, citing magnetic strips that appear symmetrically around mid ocean ridges, there was still widespread disbelief. As Vine says;
‘in general, it went over like a lead balloon. That might seem surprising now, but most people didn’t believe it…they called it a startling, improbable idea.’
Had the science media operated then as it does now, there would no doubt have been headlines claiming the theory had been proved at this early stage, long before the cautious scientific establishment agreed. But it took, quite rightly, repeated publications and confirmatory data to really establish plate tectonics as the driving force behind contintental drift. As Science Media Centre Director Fiona Fox said in her evidence to the Leveson enquiry, headlines claiming ‘breakthroughs’ rarely present the end stages of research, but more often the first tentative steps.
In the case of plate tectonics, it was only a few years before a culmination of evidence and research carried out by numerous scientists began to turn skepticism to acceptance. What a shame Darwin wasn’t around to witness the excitement of that time, when centuries of theorising about the earth’s continents finally paid off with the brilliant work of Fred Vine, Dan McKenzie and so many others.
Visit our YouTube channel for more clips from the film…