German Expedition Discovers the Mid-Atlantic Ridge
The German Meteor expedition, which took place from 1925 to 1927, was a groundbreaking oceanographic mission initiated in the context of post-World War I economic pressures. Originally aimed at exploring the potential for extracting gold from seawater, the expedition ultimately played a pivotal role in mapping the ocean floor. Utilizing newly developed echo sounders, the Meteor was able to produce detailed profiles of the deep seafloor, revealing the presence of the Mid-Atlantic Ridge, a significant underwater mountain range that runs along the Atlantic Ocean's north-south axis.
Led initially by scientist Alfred Merz and later by Georg Wüst, the Meteor traveled over 41,000 miles and conducted extensive surveys at numerous hydrographic stations, collecting data that challenged existing maps of the ocean floor. Although the expedition's findings did not immediately gain recognition for supporting the theory of continental drift proposed by Alfred Wegener, they contributed to the emerging understanding of plate tectonics, which gained traction in later decades.
The discoveries made by the Meteor laid the groundwork for modern geological science, illustrating the dynamic nature of the Earth’s crust and the continual reshaping of our planet's geography. Today, the Mid-Atlantic Ridge is recognized as a key feature in the study of tectonic plates, demonstrating the profound impact of the Meteor expedition on earth sciences.
German Expedition Discovers the Mid-Atlantic Ridge
Date April, 1925-May, 1927
Using a newly developed echo sounder, the Meteor, a refitted German gunboat, made the first transoceanic crossing with closely spaced soundings, leading to the discovery of the Mid-Atlantic Ridge.
Locale Southern and equatorial Atlantic Ocean
Key Figures
Alfred Merz (1880-1925), German geographerFritz Haber (1868-1934), German chemistGeorg Wüst (1890-1977), German oceanographer and student of Merz
Summary of Event
The initial purpose of the German Meteor expedition was economic. In 1872, E. Sonstadt reported that the oceans contained a gold concentration of 65 milligrams per metric ton of seawater. The Treaty of Versailles (1919), which ended World War I, required that Germany repay its enormous war debt in gold, and Fritz Haber, a German chemist, proposed that gold extracted from the international seas might solve the problem.
The Treaty of Versailles prohibited the German navy from sending ships to foreign ports; however, in 1919, a member of the German admiralty, Captain Nippe, persuaded authorities to allow a German vessel to be outfitted and sent on a major peacetime oceanographic expedition. The Meteor, a class C gunboat, was selected for the study. Alfred Merz, an adviser to the German navy, was named the chief scientist of the Meteor. After Merz’s death, Georg Wüst took over leadership of the oceanographic data and study, which was to take place in the Atlantic Ocean.
The Meteor was to be equipped with the newly developed echo sounder, a device used to find the distance and direction of objects under or partially under the water. An echo sounder works by measuring the time it takes a sonic or ultrasonic pulse emitted by the sounder to reach the object below and then return to the sounder. The time intervals and other data are then converted into numerical reference points of distance and direction. The navies of the world use echo sounding to chart the positions of foreign ships and submarines. During peacetime, echo sounders are used to locate sunken ships, find schools of fish, and map the profile of the seafloor.
The Meteor expedition marked the first use of echo sounders to map the profile of the deep seafloor. With the exception of the Meteor, no such detailed maps were available before World War II. The profiles aboard the Meteor were closely spaced echo soundings taken by extremely diligent workers, which only made the recordings that much more accurate and detailed. Moreover, a new anchor system had been developed that enabled the ship to anchor in deep waters.
On April 26, 1925, the Meteor left for Buenos Aires, Argentina, to start work on the planned sections in the South Atlantic. Actual surveys began on June 3, 1925. Merz was in charge in spite of his illness; however, by the time the vessel arrived at the fifth hydrographic station, his condition had worsened to the point that the captain ordered the ship to return to Buenos Aires so that Merz could receive medical attention. Merz then turned the leadership of the scientific part of the expedition over to the captain. In reviewing the work along the first section, the captain found that the acoustic depth sounder had revealed that much of the bottom had been incorrectly charted.
After completing the thirteenth traverse in the equatorial Atlantic Ocean, the Meteor sailed for Germany, arriving home on May 29, 1927. In two years, the Meteor had traveled more than 41,943 miles (67,500 kilometers), had collected data at 310 hydrographic stations, had anchored ten times in deep ocean, and had made approximately 70,000 soundings of ocean depths. As a result, the expedition was the first to reveal the true ruggedness of the ocean floor.
The significant discovery of the Meteor was that a continuous ridge (the Walvis Ridge) runs in a southwesterly direction from the vicinity of Walvis Bay, southwest Africa. (A ridge is a long, narrow elevation on the seafloor.) This in turn led to the discovery of the Mid-Atlantic Ridge. It runs along the north-south axis of the Atlantic and is basically a long, curving zone of mountains, volcanoes, and fractured plateaus. This ridge’s now-familiar herringbone pattern was first suggested in 1935 by Wüst and Theodor Stocks.
Significance
The Meteor expedition’s discovery of the Mid-Atlantic Ridge was a significant event. Unfortunately, this finding was not recognized widely at the time as being enough to support the theory of continental drift. That theory had continued to generate controversy and debate among scientists ever since 1912, the year it was first proposed by the German geophysicist and meteorologistAlfred Wegener . Wegener’s theory stated that the earth was once made up of one large ocean and one large landmass. Gradually, this supercontinent split into two parts. Additional separations and “drift” continued to occur across many millions of years, eventually resulting in the seven continents as they have come to be known.
As modern science now recognizes, these massive continental “plates” tend to drift apart at divergent boundaries. These boundaries may be seen as the midoceanic ridges such as the Mid-Atlantic Ridge. Such rending of the earth’s crust brings with it great earthquakes and great flows of volcanic materials that, as they pile up in the “cracks,” slowly create ridges.
In the 1950’s, a new generation of equipment and instruments was introduced that led to an explosion of data supporting the theory of continental drift, or “plate tectonics,” as it is now called. Continuously recording echo sounders, magnetometers, temperature probes, explosion seismometers, piston corers, dredgers, and deep-sea submersibles were used not only to discover additional evidence to support the theory of continental movement but also to add to the sum of knowledge about deep-sea activity.
The Meteor’s discovery was a midpoint during the development of the proposed theory of continental drift in 1912 and the concept of plate tectonics that became widely accepted in 1968. Earth scientists realize now that the positions of landmasses are not fixed. The separation of continental plates has resulted in the formation of new ocean basins, and older segments of the seafloor are being recycled continually in areas where deep-ocean trenches are found. This profound reversal of scientific opinion has been described as a scientific revolution, one in which the Meteor expedition played a pioneering role.
Bibliography
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Medwin, Herman, et al. Sounds in the Sea: From Ocean Acoustics to Acoustical Oceanography. New York: Cambridge University Press, 2005. Textbook aimed at students in oceanography, engineering, and physics describes the tools scientists use to examine the characteristics of physical and biological bodies in the oceans.
Menard, H. W. The Ocean of Truth: A Personal History of Global Tectonics. Princeton, N.J.: Princeton University Press, 1986. A volume ideally suited for high school and college readers who would like an overall view of the topic without technical language. Very informative.
Pickard, George L. Descriptive Physical Oceanography: An Introduction. 5th ed. Elmsford, N.Y.: Pergamon Press, 1990. A nontechnical introduction to oceanography for undergraduates in the sciences and advanced high school students who wish to learn something of the aims and achievements of this field of study. Includes bibliography and index.
Sears, M., and D. Merriman, eds. Oceanography: The Past. New York: Springer-Verlag, 1980. Collection of papers from the Third International Congress on the History of Oceanography. An excellent reference source for graduate students and researchers, as most chapters include numerous notes and references. Few illustrations.
Thurman, Harold V., and Alan P. Trujillo. Introductory Oceanography. 10th ed. Upper Saddle River, N.J.: Prentice Hall, 2003. College-level introductory text is extensively illustrated and provides a very good general survey of the topic. Each chapter concludes with a glossary and references.