Genesis of a geophysical icon - and a clarification for the Royal Society

 

A while ago, during our virtual conversation on the forum at About.com:Geology, Andrew Alden commented that it must have been interesting to be a student at Cambridge in the 1960s when the fundamentals of plate tectonic theory were being constructed and argued over. It certainly was. I started as an undergraduate in 1965, the same year that what has now come to be referred to as a "geophysical icon" was published - the Bullard, Everett and Smith reconstruction of the circum-Atlantic continents. The paper "gave rise to new ideas and set new approaches in motion, whose consequences are still being worked out today. The paper has been cited over one thousand times in refereed journals, and after over forty years is still cited about ten times per year." (I'll reveal the source of the quote shortly).

Last autumn, I was delighted to find that the Royal Society here in London (where else?) had set up, to celebrate the society's 350th anniversary this year, a website they call "Trailblazing - three and a half centuries of Royal Society publishing." As the site describes, "Trailblazing is a user-friendly, ‘explore-at-your-own-pace’, virtual journey through science. It showcases sixty fascinating and inspiring articles selected from an archive of more than 60,000 published by the Royal Society between 1665 and 2010." It's very well-structured around a timeline with significant scientific events and links to the sixty classic articles, all of which can be downloaded entirely for free. I was pleased to find, from 1676, a letter from the great Dutch inventor of microscopes and observer of all things minute (including sand - as I described in the book) - Anthony van Leewenhoek; the paper is titled

Observations, Communicated to the Publisher by Mr. Antony van Leewenhoeck, in a Dutch Letter of the 9th of Octob. 1676. Here English'd: concerning Little Animals by Him Observed in Rain-Well-Sea. and Snow Water; as Also in Water Wherein Pepper Had Lain Infused

or, as it appeared in the original - don't you just love the verb "to English"?

 

From later centuries, you can sample observations on the transit of Venus, the discovery of a comet by the first recognised female scientist, the invention of the Davy safety lamp, Maxwell's synthesis of the theory of electromagnetism, the proof that fingerprints are unique, the development of penicillin - and much, much more. But I was particularly delighted to find that there, in 1965, was the "geophysical icon" - the Bullard, Everett and Smith reconstruction. But my delight was tempered when I read the information provided on the paper that included the statement "In 1965, Sir Edward Bullard presented his paper on The Fit of the Continents around the Atlantic to a Symposium at the Royal Society." True, Sir Edward did present the paper but to describe it as "his paper" is a bit much.

You see, I happen to know very well the "Smith" and will readily describe him as one of the great influences on my life as a geologist: Alan Gilbert Smith was my thesis supervisor at Cambridge, but he was much more than that - he was a mentor (and intellectual tormentor), and an inspiration, and he remains a great friend. He retired, officially, a couple of years ago but continues to work indefatigably - here's a picture of him taken not long ago near the geology department by Richard and Jackie Fortey:

 

But back to my point - the iconic image of the circum-Atlantic continents is routinely referred to as "the Bullard fit" - yes, Bullard started the ball rolling, but it wasn't his fit, it was Everett and Smith's. Alan is a very mild-mannered, modest, and unassuming character, but he and Jim Everett published, a couple of years ago, a fascinating account of the story and the work behind the icon - "Genesis of a Geophysical Icon." It's from their introduction that the quotation above comes, and here's part of their summary:

The final result is sometimes referred to as ‘The Bullard fit’ - a term that Bullard himself used in a popular article about the work in the Scientific American (Bullard 1969). It should be clear from the foregoing account that Bullard had the initial idea for a quantitative fit, but the methodology and its execution were the work of the authors of this paper.

Not a dogmatic or argumentative statement, simply a setting-straight for the record - which is what I'm doing here for the Royal Society.

Their paper is a fascinating account of the historical context (the debate between the "fixists" and the "drifters," spurred on by the fixist pronouncements of the physicist Sir Harold Jeffreys and the pioneering early continental fits of Warren Carey), the intellectual environment at the Cambridge Department of Geodesy and Geophysics (where it all happened, headed by Bullard), the cast of characters, and the detailed work of Everett and Smith. It also contains a description of Alan Smith's path to participation in the reconstruction - and the revolution:

Alan Smith had graduated from Cambridge in physics and geology and went to Princeton for graduate work, where Harry Hess (1906 - 1969) was beginning to put together his ideas on ocean-floor spreading. Though fascinated by Hess’s ideas, he was unconvinced of their correctness, and also of Carey’s exposition of oroclines and sphenochasms - which Carey presented at a graduate seminar in Princeton. Smith was also heavily influenced by Jeffreys, who had presented the apparently irrefutable arguments outlined above, that the forces needed to move continents around were much larger than any that had so far been proposed. While completing his PhD, Smith was fortunate to have been employed as a research associate by Bill Bonini at Princeton, during which time he learned computer programming. He joined the Department of Geodesy and Geophysics as a research assistant at the end of 1963 on a project whose aim was to date the rocks on the conjugate margins of South America and Africa, thereby placing some time constraints on the break-up of the two continents. But on learning of Everett’s work, Smith became involved with him in applying his method to the North Atlantic continents, providing much-needed geological expertise. He became the third member of a trio of geophysicists, highly sceptical about continental drift but deeply involved in ‘fitting continents together’.

"Everett's work" refers to the extraordinary computer programming skills of Jim Everett, who single-handedly invented the methodology; he manually digitised the continental margins at a range of depth contours (to test various positions for the true edge of the continental crust), and essentially re-invented Euler's fixed-point theorem of spherical geometry, of which he seems to have been blissfully unaware. Everett had been set on his way, as Bullard's PhD student, by Sir Edward simply demanding to know how good the fit - and the misfit - might be. Alan Smith provided the "geological expertise" and the rest, as they say, is history - or iconography.

But it took the radical cross-disciplinary insights of the "heroes" of plate tectonic theory before the whole thing came so elegantly and so compellingly together - something that we take for granted today, however much we continue to refine and develop it. As Everett and Smith write:

At the time of our circum-Atlantic reconstructions, the dominant opinion about continental drift was changing from dismissive to agnostic. Like most other earth scientists of the time, we had found Vine and Matthews’s (Vine and Matthews 1963) evidence of ocean-floor spreading baffling. We realised that the continents probably had fitted together at some time in the past, but many of us mentally assigned their break-up to a very early period in the evolution of the Earth. When the evidence from the distribution and nature of seismic activity, coupled with the ocean-floor spreading, gave rise to plate tectonics (e.g. Isacks et al. 1968; McKenzie and Parker 1967; Morgan 1968) then the significance of these best-fit computations became abundantly clear.

Alan Smith continues to contribute very actively (to say the least) today - see the photo below - in fieldwork, in tectonics, in paleoreconstructions - and, very enthusiastically but questioningly, in stratigraphy.

 

It is an honour to know Alan - as a friend as well as a mentor. But he has always asked the damndest questions and always with a characteristic quizzical smile. However, I learned long ago that trying to answer his questions more often than not leads to an entirely different - and better - way of looking at things. This last summer he spent some time with us in France. We spent a great few days rooting around the volcanoes and geomorphology of the Puy de Dome region retracing the footsteps of early nineteenth century geology - but that's for another post. I had also taken him to some of my favourite outcrops in the mountains of the Corbières, the frontal thrusts of the Pyrenees. The geology, as you can see, is spectacular - and here's Alan, I suspect asking one of his damn questions.

 

[The Royal Society paper is freely available at http://rsta.royalsocietypublishing.org/content/258/1088/41. Unfortunately, the Everett and Smith paper is not easily available. It was published in the journal Earth Sciences History (2008, vol 27, no.1, pp1-11); if anyone is keen to see it (and it is a fascinating read) just e-mail me and I'll send the PDF).
 

Comments

[Callan Bentley]

Great post!

[jules]

Michael,

I don't remember now where I saw the reference(I peruse to many sites!)to the author, H.W. Menard and the book below,"Oceans of Truth"; but I have just ordered a used copy from Ammzon and was wondering if you are familiar with this scientist who also was involved in those early days when the theory of plate tectonics was being worked out.

http://www.amazon.com/Ocean-Truth-Tectonics-Princeton-Paleontology/dp/0691084149/ref=sr_1_2?ie=UTF8&s=books&qid=1266770007&sr=1-2

http://www.oac.cdlib.org/findaid/ark:/13030/tf5g500826/

Thanks for letting us know about the Royal Society's new site and the personal insights into those who helped bring this revolutionary idea to fruition.

[Sandglass]

Yes, indeed I am - Menard was a great marine geologist and one of the "heroes" of the history of plate tectonics. However, I have to admit that I haven't read "Oceans of Truth" - thanks for reminding me!

[Andrew Alden]

Carey's lecture at Princeton also deeply impressed Eldridge Moores. I've written elsewhere that Warren Carey was very important as an irritant, one of those people that Thomas Henry Huxley meant when he praised the "fruitful error, bursting with the seeds of its own demise." People were so riled by Carey and his expanding Earth that they were knocked out of their orbits.

Lovely to see you expand on my question here on your blog.

[Andrew Alden]

Jules, you remind me that Menard served as head of the US Geological Survey in the late 1970s, so he was my boss at one point in my career.

[Sandglass]

Carey was indeed a stimulating irritant. But one of the problems was that the irritation over his expanding earth detracted from the value of his continental fits. As Everett and Smith point out, his tectonics "apart from global expansion, actually contained the essence of continental motions." It's impressive today to think that Carey achieved a remarkably good visual fit of the continents (particularly at the 2000m contour) through moving tansparent spherical caps around a 75 cm globe. And I like Everett and Smith's comment that "Carey's work formed a part of the disparate ideas and evidence that at the time made any discussion about the Earth such a vigorous and often emotional affair."

Incidentally, Alan Smith and Eldridge Moores became lifelong colleagues and friends after meeting at Princeton in those heady years.

[Jules]

Andrew,

Thanks... Lots of connections in the field of geology. I thought I had seen the reference to Menard on your site, but now I can not locate where I first read about his book, however it aroused my interest enough to want to read his work, hence I searched for it on Amazon. I also purchased a very inexpensive copy of Islands,(the Scientific American Library series) that he wrote in the late 80's.

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