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Alfred Wegener with pipe and parka (Alfred-Wegener-Institut, Germany)

and Africa lined up if the continents were once together, and belts of distinctive rock types, such as coal, also matched on different continents if they were restored to his hypothesized supercontinent of Pangaea (meaning all land). Alfred Wegener studied the fossils and found that narrow belts of distinctive fauna and flora, such as the reptiles Mesosaurus and Lystrosaurus, matched on the former supercontinent and that the Glossopteris flora from the southern continents also matched on his restored Pangaea map. Wegener wrote an extended account of his continental drift theory in his 1915 book Die Entstehung der Kontinente und Ozeane (The Origin of the Continents and Oceans, translated into English in 1966). In this book, he argued strongly against the land bridge hypothesis, stating that continents are made of different material (granite) that is less dense than the oceanic crust (made of basalt), and that the weaker material should be floating on the denser substratum much like an iceberg on water. He also provided evidence of the continents moving up and down relative to sea level, noting that the continents in northern latitudes rise up when glaciers retreat from an area, rising or rebounding in response to the reduction of weight on the crust. He reasoned that the continents must also be moving laterally, explain ing why coastlines of different continents could be restored so perfectly.

Wegener also argued against the then leading model for the origins of mountains. Others, such as the Tasmanian geologist S. Warren Carey, advocated that mountains formed by the cooling and shrinking of the Earth and that as the Earth shrunk mountains formed as wrinkles to accommodate the change in surface area. Wegener said that model did not account for the distribution and spacing of mountain ranges. He argued instead that they formed on the edges of continents that had drifted and collided with other continents, such as where India was currently crashing into Asia.

As a meteorologist he began to look at ancient climates, using paleoclimatic evidence he found to strengthen his theory of continental drift. one of his strongest arguments was that of the patterns of the Permian-Carboniferous glaciation on Pangaea. If the continents were restored, the paleoglaciers would have a pattern of all the ice moving away from a central core near the South Pole about 280 million years ago, whereas if the continents had their present distribution, then the glaciation patterns would be random and would require more water to make the amount of ice needed to explain the patterns than is available on Earth.

Wegener was by no means the first to think of the theory of continental drift. However, he was the first to go to great lengths to develop and establish the theory. His ideas were met for the large part by the geological community with strong opposition, anger, and hostility. Many geologists noted that Wegener was not trained as a geologist, so did not believe him, and published many disparaging comments on his theory and even his personality. Wegener had evidence for continental drift but could not provide a mechanism. Without a driving force he could do little to argue against those who said there was no driving mechanism, except to smoke his famous pipe and remain silent. He did argue, however, for the validity of his observations, especially that the continents move, that the movement causes deformation at their edges, and that earthquakes and volcanoes are associated with the edges of these great moving continents. It was not until 40-50 years later that proof of Wegener's theories came, in the form of the many proofs of plate tectonics that came with the geological revolution in the 1960s.

Wegener made his fourth and final trip to Greenland in the spring of 1930, never to return. The expedition started with 22 scientists and technicians, but bad weather plagued and delayed the initial setup of the base camp from May until mid-June, and the inland camp at Eismitte had only basic supplies. On September 21 Wegener led a team of 15 dogsleds

Werner, Abraham Gottlob

to bring supplies to Eismitte, but bad weather convinced 12 of the 13 local Greenlanders to turn back after one week. After 40 days of traveling, Wegener and his two remaining companions reached Eismitte, delivered the supplies, and then celebrated Wegener's 50th birthday on November 1st. The next day Alfred and Rasmus Villumsen, his Greenlander companion, set out to return to base camp, but never arrived. In the spring, on May 12 a search party found Wegener's body, buried in the snow in sleeping bags, and they concluded he died of a heart attack in his sleep, from exertion of the trip. Villumsen was never found. His friends and companions erected an ice mausoleum over Wegener's body, all of which have since been covered deeply in the snow and ice of the glacier, and Wegener's body has become part of the glacial ice cap he devoted much of his life to studying.

See also Gondwana, Gondwanaland; historical geology; plate tectonics; supercontinent cycles.

FURTHER READING

Koppen, Vladimir, and Alfred Wegener. The Climates of the Geological Past. London: D. Van Nostrand, 1863.

Wegener, Alfred. The Origin of Continents and Oceans, translated by John Biram. Mineola, N.Y.: Dover Publications, 1966.

-. Thermodynamik der Atmosphare. Leipzig: Verlag

Von Johann Ambrosius Barth, 1911. Wegener, Elsie, ed., with the assistance of Dr. Fritz Loewe. Greenland Journey, The Story of Wegener's German Expedition to Greenland in 1930-31 As Told by Members of the Expedition and the Leader's Diary (Translated from the seventh German edition by Winifred M. Deans). London: Blackie & Son Ltd, 1939.

Werner, Abraham Gottlob (1749-1817) Prussian, German Geologist, Mineralogist Abraham Werner was enormously influential in the field of geology. Werner developed techniques for identifying minerals using human senses, and this appealed to a broad audience interested in learning more about geology. Werner also proposed a new classification for certain geologic formations. In the 18th century, rocks were explained and were classified into three categories with accordance to the "biblical flood," including Primary for ancient rocks without fossils (believed to precede the flood), Secondary for rocks containing fossils (often attributed to the flood itself), and Tertiary for sediments believed to have been deposited after the flood. Werner did not dispute the commonly held belief of the biblical flood, but he did discover a different group of rocks that did not fit this classification—rocks with a few fossils that were younger than primary rocks but older than secondary rocks. He called these "transition" rocks. Geologists of succeeding generations classified these rocks into the geologic periods still accepted today. Werner is the father of the discredited school of thought called Neptunism, that proposed that granitic rocks crystallized from mineralized fluids in the early Earth's oceans.

Abraham Gottlob Werner was born in Wehrau of Prussian Silesia in southeastern Germany on September 25, 1749. He was born into a mining family, and his father was a foreman at the foundry in Wehrau. Educated at Freiberg and Leipzig, Werner studied law and mining, then became an inspector and teacher of mining and mineralogy at the influential Freiberg Mining Academy in 1775. When he was studying at Leipzig in 1774, Werner wrote his first book on mineralogy, Vonden dusserlichen Kennzeichen der Fossilien (On the external characters of fossils, or of minerals), a book that became influential in its field. Werner did not publish many books or works after this, but instead was known through his lecturing, his mentoring of students, and many interactions with colleagues. Werner was plagued with health problems his entire life and rarely traveled; he spent his time quietly near Freiberg. When he was young he enjoyed mineral collecting, but as age and disease took their toll he abandoned field work. He died in Dresden on June 30, 1817.

Werner was one of the most important geologists of his time, in an era when the geologic and scientific community was actively presenting evidence that the geologic record preserves a history of the Earth that is very different from that advocated by the church at that time. Werner divided the strata of Europe and the world into five main series, including the Primitive, Transition, Secondary (or stratified), Alluvial (or Tertiary), and Volcanic (or Younger). His theory of neptunism, which was advocated by the church, was based on his idea that the early Primitive granites were crystallized from the sea before land had emerged from the worldwide ocean. Neptune was the Roman name for the ancient Greek god of the sea, Poseidon, and Werner's belief that nearly all rocks could be explained as precipitates from the ocean led to his theory's being called neptun-ism. Werner's Transition series included limestones, dikes, sills, and graywackes, which he suggested were universal formations that extended around the entire world. These were followed by the Secondary or Stratified series, including layered fossiliferous rocks and lava flows. Werner interpreted these to reflect the emergence of mountains from the primeval sea, depositing the products of their erosion on their flanks. These are followed by the Alluvial or Tertiary rocks consisting of poorly consolidated sands, gravels, and clays deposited as the oceans withdrew and

Werner, Abraham Gottlob receded from the continents. Finally, the Volcanic series consisted of younger lava flows associated with volcanic vents that Werner suggested were the product of subterranean coal fires.

Werner's ideas were debated, particularly his ideas on the origin of granites and basalts. Many other geologists noted that volcanic rocks occurred in places not known to have coal beds and thought they may have formed from melts of rock at depth. This alternate school of thought, called plutonism, pioneered by James Hutton, later became dominant and is accepted today along with the school of thought called uniformitarianism, whereby processes observed to create specific effects on the modern Earth may be assumed to be responsible for creating similar effects in the geological record. Werner was also criticized on the basis that the volume of water required by his theory for a universal ocean was enormous. He managed to avoid this question somewhat by suggesting many of the waters escaped or evaporated to space.

See also historical geology; Hutton, James; origin and evolution of the Earth and solar system.

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