Nina's Reading Blog

Comments on books I am reading/listening to

Evolutionary Catastrophes: The Science of Mass Extinction

Posted by nliakos on October 29, 2011

by Vincent Courtillot, translated by Joe McClinton. Cambridge, 1999 (original French version published in 1995 by Editions Fayard)

In America, we think that the dinosaurs were wiped out by an asteroid that hit the earth somewhere in Mexico 65 million years ago, changing the climate and making it impossible for the great beasts to survive.  Vincent Courtillot and his colleagues have a different scenario: yes, there was an asteroid, but in what is now western India around Bombay, there were also massive volcanic eruptions lasting perhaps a hundred thousand years. This series of eruptions, which produced the Deccan Traps (a thick layer of basaltic rock resembling steps, or “traps” in several Scandinavian languages), also coincided with the demise of the dinosaurs. But as Courtillot explains, it is just one of seven gigantic trap-forming series of eruptions, all of which correspond in time to a mass extinction of species marking the boundary between two geological eras. (There are other traps, but these do not correspond to major species die-offs.) Courtillot shows the reader that while an asteroid may have contributed to the extinction of the dinosaurs, they were probably already under intense pressure from climate changes resulting from the ongoing eruptions halfway around the world from where the asteroid hit.

I am proud to say that Vincent Courtillot is a friend of mine; I have known him for forty years.  When he first told me about his idea that volcanoes did in the dinosaurs, Walter and Luis Alvarez had not yet found the crater that seems to have convinced everyone on this side of the Atlantic, at least, that their asteroid theory was correct.  I remember thinking, when they did find it, that he must have been disappointed to find that his theory had turned out not to be true.  Ha! not at all.  He remains convinced that the eruptions that produced the traps were responsible not only for the disappearance of the dinosaurs but for the disappearance of millions of species that formerly lived on the Earth.  With meticulous care, he  builds his case, one piece of evidence at a time.

Although I am not a scientist and could not follow all of the explanations in the book, it is a book written for a general audience; it carefully introduces each new concept to the non-expert, as well it must, as the science of the traps is truly an interdisciplinary endeavor, requiring the expertise of geologists, paleontologists, physicists, chemists, engineers, oceanic and atmospheric scientists, mathematicians and computer scientists. (The author is himself a geophysicist specializing in paleomagnetism.)

Reading this book reminded me of what a dynamic thing science is. You may think things have been pinned down, but another discovery can always open the way to a new path of inquiry.  It is always a good idea to keep an open mind.


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