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Supercontinent: Ten Billion Years in the Life of Our Planet
Supercontinent: Ten Billion Years in the Life of Our Planet
Ted Nield
Harvard University Press, 2007
304 pp., 29.95

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by Stephen O. Moshier


The Upper Crust

Supercontinent: Ten Billion Years in the Life of Our Planet.

Editor's Note: This article first appeared in the July/August 2008 issue of Books & Culture. Its subject is a book that traces "the long and convoluted history of continental drift." Along the way, reviewer Stephen Moshier has some illuminating things to say about science, religion, creationism, and the misunderstandings that often bedevil discussions of these intertwined subjects.

Continental drift first captured my imagination in elementary school. The front page of a particular Weekly Reader featured a drawing of the earth floating in space. But this globe showed the continents all bunched together in a single landmass scientists called Pangaea. Of course! Why hadn't I noticed that the Atlantic coastlines of the Americas, Europe, and Africa fit together so perfectly, like pieces of a planetary jigsaw puzzle? The article announced that finally, after many years of investigation, scientists had enough evidence to show that, indeed, continents drift. We were witnessing a major revolution in science, what philosophers call a paradigm shift. For in the middle 1960s, the idea of continental drift was at the tipping point of acceptance by the scientific community.

In Supercontinent: Ten Billion Years in the Life of Our Planet, author Ted Nield writes that the long and convoluted history of continental drift is actually three stories. The first story is about the scientific work that led to the modern geological paradigm of plate tectonics. Nield is keen to make this a story about people, including some of the most colorful scientists and explorers of the 20th century. The second thread is the story of earth history, with its changing geography, climate, and ecology.[1] The third thread might be the most interesting to many readers, as Nield explores how Pangaea belongs to the company of "lost continents" that have captured imaginations, even fueled religious convictions, from Aristotle's Atlantis to the new age Mu. Nield weaves a thorough history of plate tectonics for popular audiences, drawing from historians of science (including Naomi Oreskes) and his personal relationships with contemporary workers at the cutting edge of research and discovery. As editor of Geoscientist, the magazine for Fellows of the Geological Society of London, Nield knows the material intimately and communicates it in a compelling manner.

The theory of plate tectonics is one of the major scientific achievements of the 20th century. Most geology textbooks tell the story as if it involved only two or three scientists, but Nield celebrates the wider cast of characters. Every student of geology learns about Alfred Wegener (1880-1930), the German atmospheric scientist who showed that rocks, fossils, and mountain belts match exactly where the continents can be fitted together. As a specialist on climates, Wegener was particularly interested in the distribution of glacial deposits from the Permian geologic period found on all the southern continents. He argued that if the continents at that time were in their present positions, an ice sheet would have implausibly extended from the South Pole to the equator, covering wide expanses of open ocean. The first edition of Wegener's Origin of Continents and Oceans was published in 1915, but his ideas were not adopted in his lifetime. Wegener perished in Greenland attempting to measure the movement of that particular icy landmass from Western Europe.

Nield resurrects the memory of forgotten and courageous 19th-century European geologists who mapped rocks in India, South Africa, and Australia, work that contributed to Wegener's synthesis. Preceding Pangaea, continents with names like Lemuria and Gonwanaland were proposed to explain distributions of organisms on southern continents that would seem to have required connections by land (so-called land bridges). But scientists eventually abandoned those hypothetical terrains as new evidence emerged.

While geologists were mapping the continents and comparing notes, geophysicists were learning about heat in the earth and developing models for how mountains rise and fall, leading to a comprehensive understanding of how the earth works. The synthesis of continental and marine geology with the geophysics of the inner earth came after World War II. Maps of the seafloor revealed the submarine boundaries of lithospheric plates that merged with mountain belts and fault zones on the continents. It turned out that continents are like lunch trays on a conveyor belt. Magnetic properties of the ocean crust revealed patterns of seafloor spreading away from mid-ocean ridges (where the conveyor belt begins). Mountain ranges, explosive volcanoes, and deep earthquakes mark the locations of plate convergence, even creating deep ocean trenches where ocean crust is pushed back into the earth (where the conveyor belt ends). You get Pangaea at the cafeteria when trays approaching the dishwasher collide into a mangled mess.

Nield explores sociological factors in the gradual acceptance of plate tectonics, suggesting that science is a kind of supercontinent. Just as plates are slowly shifted by a variety of forces, paradigm shifts in science can be preceded by decades of give and take between scientists. Wegener's idea was accepted earlier and more widely in Europe than in America. Frankly, American scientists were put off by Wegener's rather bombastic pronouncements (or at least the tone employed by his English translator). Nield suggests that European science was driven by inductive methods (allowing explanations to emerge from the data set), while American scientists practiced a democratic form of deduction called "multiple working hypotheses" (collection of data to deliberately test or reject numerous possible explanations). By American standards, Wegener and his cohort were jumping the gun. Also, Nield explains that scientific advances can stall or get sidetracked if scientific models become confused with reality. U.S. geographic surveyors were committed to a model of crust properties that was useful for correcting local gravity variations but carried the assumption that rocks do not flow over long periods of time. Europeans embraced a more dynamic model of the inner earth, making the idea of moving continents quite tenable. (While Nield doesn't disparage or completely neglect the role of U.S. scientists in the development of plate tectonics, I feel he ignores some important contributions from the New World to the emerging synthesis after World War II.)

The final third of the book is devoted to discoveries and theories about the earth before Pangaea. Nield uses the analogy of palimpsest texts to describe how geologists use ingenious geochemical methods to unravel the history of the earth's oldest rocks. The work has led to the "discovery" of supercontinents that preceded Pangaea: Ur some three billion years ago and Rodinia about one billion years ago. The influence of these Precambrian tectonic revolutions on the history of life is emerging from the supercontinent of science. Ur—with its marginal shallow seas—was a template for cyanobacteria growing layer upon slimy layer on the seafloor, converting carbon dioxide in the atmosphere into oxygen. Rodinia was an equatorial supercontinent, whose position and fragmentation may have promoted global cooling to the point of converting earth into a temporary snowball (or slushball, depending on the scientist). The appearance of multicellular life with three-layer bodies during the time of Rodinia's icy fragmentation about 650 million years ago implies some connection. "On the supercontinent of science, everything must fit together," the author reflects.

Nield considers how sometimes, in order to advance cultural or religious agendas, "scientific ideas about possible lost worlds have escaped the domain of science and taken on new life as myth." First there was the case of Lemuria,[2] which was legitimized by Friedrich Engels and H. G. Wells as the missing nursery of humankind. Tamil religious scholars reasoned that Lemuria must be their mythic homeland Kumarikkanam. Spiritualist and Theosophy founder Helena Blavastsky claimed Lemuria as the paradise of pre-human ancestors who lived there with dinosaurs, before moving the whole kit and caboodle to another lost continent, Mu, in the south Pacific. Mu was promoted by a cottage industry of late 19th-century spiritualists on the basis of some wishful mistranslations of Mayan inscriptions. The account of ancient earth in the New Age Urantia Book refers to a supercontinent from which life originated one billion years ago, in embarrassing near-agreement with the scientific Rodinia.

Nield's commitment to philosophical naturalism is quite obvious throughout the book. He concludes on a blustering note, rejoicing in science's triumph over religion and mythology. Human hubris—the kind that inevitably follows from faith in an absolute creator, he contends—hinders the advance of knowledge, because "science tells us there is no absolute knowledge of any kind." Nield doesn't explain how scientific ancestors such as Isaac Newton, Robert Boyle, and (first Cambridge professor of geology) Adam Sedgwick—devout Christians all—managed somehow to overcome this handicap, not to mention the thousands of Christians and followers of other religious traditions in the sciences today. Nield compares the Tamil scholars' use of Lemuria to support their mythology with Christian creationists who, "By insisting on the literal truth of the creation myth told in the Old Testament and by vainly looking for evidence of the supernatural among the things of this world … espouse … both bad science and bad religion, demonstrating nothing more than ignorance on the one hand and lack of faith on the other." Ouch, he has a point there.

Given his concern over Young Earth creationism, Nield could have explored how this movement adopted plate tectonics. The founding document of modern creationism, The Genesis Flood by John Whitcomb and Henry Morris, was published in 1961, when many mainstream geologists still rejected continental drift. The authors could pretty much ignore the idea. But by the 1990s, Young Earthers were ready to incorporate plate tectonics into flood geology and their abbreviated view of geologic time. They simply sped up the film. The author of a creationist book popular with Christian homeschoolers proposes the "hydroplate" version, in which drift was lubricated by the release of water from a subcrustal layer via the "fountains of the deep" at the beginning of the Genesis Flood. Considering the temperature of water that is expelled from volcanoes (let alone the depths imagined by this scenario), the only safe place for Noah would have been in orbit. A more sophisticated proposal is the "catastrophic plate tectonics" model of Los Alamos geophysicist J. R. Baumgardner, who has a well-deserved international reputation on the modeling of earth-mantle convection (the process that most geoscientists believe drives continental drift). In presentations to the International Conference on Creationism, he cites experimental data on rock physics that indicate extreme weakening of material strength at mantle temperatures (though it appears he ignores other factors, such as pressure). Plugging these variables into a supercomputer, he can make continents drift at rates of meters per second, not centimeters per year (as they are moving now and geoscientists believe they have moved in the past). Here, Nield's warning about confusing scientific models with reality in nature is appropriate. When Baumgardner offers observational support for his model, he completely ignores the geology of the ocean floor (which does not support the predictions of his model) and instead chases fossil red herrings in sedimentary rocks deposited on continental crust.

While Nield's concerns over how creationists abuse science to justify their particular understanding of Scripture are legitimate, his contempt for religion is unjustified by the history of science. Indeed, Nield and too many other contemporary scientist-authors misuse science to justify their naturalism. Let's dispose of that silly idea about religion being bad for science. History shows that good ideas eventually win over bad ideas, exemplified by Wegener's Pangaea. If science is the supercontinent, why can't religion be the ocean?

Stephen O. Moshier is associate professor of geology at Wheaton College.

1. Why ten billion years if the age of the earth is estimated to be roughly 4.5 billion years? Because Nield considers how the geography of the planet might change if it is around for another five billion years.

2. For more on Lemuria, see Philip Jenkins, "Continental Drift," Books & Culture, May/June 2005, p. 24, a review of Sumathi Ramaswamy, The Lost Land of Lemuria: Fabulous Geographies, Catastrophic Histories (Univ. of California Press, 2004).


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