Alfred Wegener, around 1925
|Born||November 1, 1880
|Died||November 13, 1930
|Alma mater||University of Berlin|
|Known for||continental drift|
Alfred Lothar Wegener (November 1, 1880 – November 13, 1930) was a German scientist and meteorologist. He was born in Berlin and in 1904 he earned his PhD in Astronomy at the University of Berlin. In 1914 he was put into the German army but released from battle after he was severely wounded. He is most notable for his theory of continental drift, proposed in 1912, which hypothesized that the continents were slowly drifting around the Earth. However, at the time he was unable to demonstrate a mechanism for this movement; this combined with not enough solid evidence meant that his hypothesis was not accepted until the 1950s after he had died when numerous discoveries provided evidence of continental drift.
Plate tectonics theory[change | change source]
Wegener's theory[change | change source]
Wegener used geologic, fossil, and glacial evidence from opposite sides of the Atlantic Ocean to support his theory of continental drift. For example, he said that there were geological similarities between the Appalachian Mountains in North America, and the Scottish Highlands. Also, he said that the rock strata in South Africa and Brazil were similar.
He believed these similarities could be explained only if these geologic features were once part of the same continent. Wegener said that because they are less dense, continents float on top of the denser rock of the ocean floor. Although continental drift explained many of Wegener's observations, he could not find scientific evidence to make a complete explanation of how continents move.
Criticism[change | change source]
All except for one of Dr. Wegners students did not believe Wegener's theory and thought it was foolish. Some critics thought the old theories of giant land bridges could explain the similarities among fossils in South America and Africa. Others argued that Wegener's theory did not explain the forces that would have been needed to move continents to such great distances. Wegener thought that the forces that moved the continents could be the same forces that made earthquakes and volcanic eruptions.
Evidence[change | change source]
During the 1960s, discoveries of sea-floor spreading and magnetic reversal proved that Wegener's theory was real and led to the theory of plate tectonics. Today geologists say that continents are actually parts of moving tectonic plates that float on the asthenosphere, a layer of partly molten rock.
References[change | change source]
- "Alfred Wegener". ucmp.berkeley.edu. http://www.ucmp.berkeley.edu/history/wegener.html. Retrieved 4 December 2010.
- Spaulding, Nancy E., and Samuel N. Namowitz. Earth Science. Boston: McDougal Littell, 2005.
- Earth Science. United States of America: Holt, Rinehart and Winston. 2001. pp. 211. ISBN 0-03-055667-8.