Wegener, Alfred

caption Alfred Wegener (From: Origin of Continents and Oceans, 4th ed.)

Alfred Wegener (1880-1930) is best known as the father of continental drift, the precursor to the theory of plate tectonics. His Ph.D. work at the University of Berlin was in astronomy, but his attention soon turned to meteorology. He maintained a boyhood fascination for Arctic exploration and participated in four research expeditions to Greenland. Another example of his adventurous spirit is that he and his brother set a world ballooning record in 1906 with one trip lasting fifty-two hours.

Wegener began his work on continental drift at Marburg University, where he became a professor of meteorology in 1909. In 1919 he moved to the German Marine Observatory and the University of Hamburg and then to the University of Graz, in Austria in 1924. In 1910, he became interested in the remarkable fit of South America and Africa, something that had been noticed for centuries. Upon investigating, he realized that the fit is even closer if the edges of the continental shelves are matched, rather than the present coastlines. American Frank Taylor was working on the same problem at the same time, but they were unaware of each other, much like Darwin and Wallace. Wegener developed his ideas more fully than Taylor and is generally given credit for the theory. Wegener first presented his ideas on continental drift in 1912 at a geology meeting, though the meeting report states that “there was no discussion due to the advanced hour.” There would be plenty of discussion, though, in the years to come. That same year, he published two papers on the subject. During World War I, Wegener was shot through the arm and later in the neck. While recuperating, he turned his ideas into a short book, Die Entstehung der Kontinente und Ozeane (The Origin of Continents and Oceans), first published in 1915. He updated and expanded the book in three later editions

caption Positions of the continents during the Carboniferous Period (top), Eocene (middle) and Quaternary (bottom) (From: Origin of Continents and Oceans, 4th ed.)

Here is a very brief and simplified summary of Wegener’s theory of continental drift. The jigsaw fit of the continents, especially South America and Africa, suggest that they were together at one time, which is a testable hypothesis. Evidence in support of the hypothesis is: 1. Mountain ranges and rock types match when South America and Africa are fit together, providing additional support that they were once connected. In Wegener’s words “It is just as if we were to refit the torn pieces of a newspaper by matching their edges and then check whether the lines of print run smoothly across” [1] 2. Plants and animals are similar in Africa and South America, suggesting a connection in the past; this connection is better explained by drifting continents than by the prevailing theory of the time that a land bridge across the Atlantic has sunk below sea level. And 3. Evidence for climates of the past, like glacial deposits in tropical regions, suggests that the continents must have been in different locations in previous times. To explain the drift, he argued that the continents are large blocks floating on the ocean crust, somewhat like icebergs floating in the ocean. A possible driving mechanism for the movement is the force of the spinning earth driving the continents away from the poles and toward the equator. He knew that this was the weakest part of his theory and he later replaced it with the suggestion of others that convection currents in the mantle are the cause, an idea now generally accepted as the most likely explanation.

Wegener had few supporters for his theory of continental drift. The response from most geologists and geophysicists, especially in the United States and to a lesser extent in Britain, was either outright rejection or a general disbelief mixed with an interest in the theory. Wegener was not a geologist or geophysicist and his outsider status likely contributed to the negative reaction he received. On the other hand, he may have come up with his outlandish ideas precisely because he was not enmeshed in the prevailing theories of those disciplines. Naomi Oreskes has studied the reaction of American earth scientists to Wegener’s continental drift theory and concluded that it was rejected largely because it was a deductively proposed grand theory; Wegener sought evidence to support it after he knew what to expect.[2] The American approach to geology at the time was much more inductive—slowly accumulating facts and letting theory emerge over time. That Wegener relied on the work of others to support his theory, rather than doing his own field work, was also viewed negatively by many geologists. What scientists choose to accept and what they reject is not a purely objective exercise.

It was not until the 1960s that advances in paleomagnetism, rock dating, and sea floor exploration were used to obtain conclusive evidence that continents do indeed drift. Then the theory of continental drift was more fully developed into the theory of plate tectonics, the most important advance in the earth sciences in the Twentieth Century.

But continental drift was more of a side project for Wegener, the meteorologist. He conducted high altitude measurements of atmospheric phenomena, using balloons and kites. He wrote a textbook, Thermodynamics of the Atmosphere, in 1911. He collaborated with his father-in-law, Vladimir Köppen, world famous for his classification system for world climates, on Die Klimate der Geologischen Vorzeit (Climates of the Geological Past) in 1924. In addition to the glacial evidence mentioned previously, Köppen and Wegener showed that tropical vegetation is found in coal deposits in regions now too cold for such plants to live, desert sedimentary deposits like gypsum and rock salt can be found in humid regions, and thick limestone deposits which form in tropical waters are found in cold regions. Wegener received many honors during his life, but only for his exploration and his research in meteorology.

Wegener made many contributions to polar meteorology, most notably for his measurements made during his four expeditions to Greenland. It was generally believed that the weather of that large island played an important role in the weather of Europe and Wegener sought to understand the atmosphere over Greenland. In 1930, he led a team collecting weather data and also making seismic measurements of the ice depth. They set up three camps along 71° North Latitude, one near each coast and one in the middle of the island. This was done using dogsleds, Icelandic ponies, and new motorized sleds designed for the expedition. The expedition got off to a late start due to ice conditions and travel problems from the motorized sleds, which never worked well. Wegener tried to bring supplies to the “Mid-Ice” camp, a 400 kilometer trip by dogsled, done with only two companions. They arrived after forty days with no supplies left and one man seriously frostbitten. The injured man was left at the camp with two others and the three survived the winter on low rations. On his fiftieth birthday, Wegener and Greenlander Rasmus Villumsen set out on the return trip to the coast. Along the way, Wegener died, most likely of a heart attack from overexertion. Villumsen likely died a few days later. Wegener’s body was discovered seven months later because Villumsen had marked the grave with skis; Villumsen’s body was never found. Wegener remains buried in the ice in Greenland.

References

  1. ^ Wegener, Alfred, 1966, The Origin of Continents and Oceans, New York: Dover Publications, 246 p., a translation by John Biram of the 4th edition (1928) of Die Entstehung der Kontinente und Ozeane.
  2. ^ Oreskes, Naomi, 1999, The Rejection of Continental Drift: Theory and Method in American Earth Science: New York, Oxford University Press, 420 p.

Further reading

  • Schwarzbach, Martin, 1986, Alfred Wegener, the Father of Continental Drift, Madison, Wisconsin: Science Tech, Inc., 241 p., a translation of Alfred Wegener und die Drift der Kontinente, 1980.
Glossary

Citation

Lee, J. (2009). Wegener, Alfred. Retrieved from http://www.eoearth.org/view/article/157036

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