Free «Continental Drift Theory by Alfred Wegener» Essay Sample

Geology is a science about the Earth. It studies the upper layers of the Earth’s crust as well as its composition, structure and evolution. Nowadays, geologists examine not only mineral, physical and chemical changes, but also the history of all the inhabitants of the planet. Geology is closely interdependent with other natural sciences including chemistry, physics, mineralogy, botany, zoology etc. There are also a lot of famous researchers, including Leonardo da Vinci, Charles Darwin, Robert Bell etc. The one that has made an outstanding contribution to the understanding of the Earth is Alfred Wegener. He developed a Continental Drift Theory in the beginning of the twentieth century. He suggested that the continents were connected together million years ago. Later, they were split apart. However, the scientist could not prove his theory as he needed a lot of additional sources that could support it. The theory was criticized a lot. Much time passed since Wegener’s work has got the world’s recognition and transformed from a myth into a separate brunch of science. It has also expanded the scope of geological research. Thus, nowadays, geologists are interested in the deeper layers of the Earth’s crust and mantle.

Alfred Wegener was born in the family of a famous scientist in Berlin. He liked science from the childhood. Wegner measured the depth of his brother’s lakes and drew maps. Physics and chemistry were his favorite subjects at school. He always dreamed about the career of a famous astronomer. Alfred graduated from the Berlin University with the highest degree. After the university, he worked with his brother in the aeronaut’s observatory in Berlin. He conducted the meteorological studies flying on the balloon. Flights were a great passion of the young scientist.

In 1906, Wegner participated in the first expedition to Greenland. Upon his return to Germany, he became a lecturer at the Marburg University. He also got married with the 19 year old daughter of his old friend and a well-known scientist Vladimir Koppen. At the beginning of the World War I, Wagener was sent to the front. There, he was wounded in the arm and neck and was demobilized. When he returned home, he published his first famous book “The origin of Continents and Oceans”. He wrote his second book “Climate of the Ancient Times” in the Naval Observatory in Hamburg.

Wegener’s first expedition to Greenland consisted of 12 scientists, one artist and 13 sailors. It was organized under the leadership of a polar explorer and writer Ludvig Myulius-Eriksen. Its aim was to explore the coast of Greenland. The expedition lasted almost two years; scientists were constantly struggling against the brutal nature and solitude. In March 1907, Wegener together with Myulius-Eriksen, Hagen and Bronlundom organized a trip to the far North of the country. Wagener returned to the base in May while the rest of the team continued the trip. Three scientists were never to come back again (Kehrt, 2013).

In 1912, Wagener was invited for the second expedition to Greenland. He was accompanied by his friend Koch and two assistants. In September 1912, they settled the camp and started preparing for the long winter. During the trip, Wegener occasionally fell on the ice. As a result, he has remained bedridden for a long time. Wegener and other researches were the first people in the world who spent the whole winter in the ice of Greenland at a temperature below -45 degrees. The expedition appeared to be extremely difficult. The scholars were constantly suffering from the extreme cold and hunger, so they had to kill their horses and dogs in order to survive (Kehrt, 2013).

In 1929, Wegener started preparing for the third and largest expedition in his life. Unfortunately, the trip was supposed to be a total failure from the very beginning. They faced a lot of problems right after the arrival to Greenland. Icebergs were overlapping on the way to the land. As a result, the expedition lost almost six weeks in vain. Despite the fact that special sleds with motor-propellers were designed for the expedition, they turned out to be too weak to overcome the long distances. That is why, scientists were forced to form the dog sledges. They were going to the Eismitte station, located 400 km away from their starting point. However, the bad weather was constantly slowing down their movement. Moreover, expedition had to leave a lot of useful cargo because the ice on the road was full of cracks and deep wells. On October, 30^th, the scientists reached the station. There, Alfred Wegener together with his assistant started the 400-kilometer route to the West Station. They took 17 dogs, two carts, and 135 kg of food. However, neither Wegener nor his companion came back to the station again. In May 1931, Wegener’s body was found frozen between Eismitte and West camp stations. The body of his assistant was not found (Kehrt, 2013).

Before the Wegener’s “Continental Drift” theory, several scientists such as Alexander Ortelius, Alexander von Humboldt and Antonio snider-Pellegrini have come to a conclusion that the shape of the continents on the sides of the Atlantic Ocean indicated that they fitted one another. It mainly referred to Africa and South America. According to Alfred Russel Wallace (1889) remarks:

It was formerly a very general belief, even amongst geologists, that the great features of the earth's surface, no less than the smaller ones, were subject to continual mutations, and that during the course of known geological time the continents and great oceans had again and again changed places with each other. (p. 341)

James D. Dana (1863) also suggested that:

The continents and oceans had their general outline or form defined in earliest time. This has been proved with respect to North America from the position and distribution of the first beds of the Silurian - those of the Potsdam epoch. … and this will probably prove to the case in Primordial time with the other continents also. (p. 732)

Thus, it was noticed long ago that the continents were joined together into one “super” continent which was driven apart in the course of time.

In 1912, Wegener proposed “Continental Drift” theory. The theory was based on the surprising similarity of continental coastlines on different sides of the Atlantic Ocean. He showed the complete identity of fossils on the continents of Africa and South America during the late Paleozoic period. There is also great identity of flora and fauna in the ocean separating the Southern Hemisphere and Indian subcontinent. Thus, he concluded that around 250 million years ago, all the Earth’s crust was assembled into a single continent. He called it Pangaea. Pangaea was surrounded by only one “great” ocean. Oceans like the Atlantic and Indian did not exist at that time. Pangaea was breaking apart very slowly in the Mesozoic era. Wagener suggested that in the Jurassic period, the super-continent was divided into two parts, the northern and southern. The northern part resembled the Asia nowadays. The second part formed present-day North-America, Greenland and Europe. Wegener suggested that the continents moved over the surface of the globe relatively to each other. For instance, South America moved away from Africa, while India reached Asia and connected with it etc. (Yount, 2009, pp.41-44).

Many years ago, in 1885, Eduard Suess also proposed a theory about a single Gondwana supercontinent. According to his theory, the continent consisted of two parts: the northern, Laurasia (North America and Eurasia without Hindustan) and the southern, Gondwana (South America, Africa, the Indian subcontinent, Australia and Antarctica) separated by the Tethys sea (Yount, 2009).

Wagener suggested that the main mechanisms that forced continental movements had been the Earth’s rotation and the mutual attraction of the Earth, Sun and Moon. The separation of the North America from Europe and Africa caused the emergence of the Atlantic Ocean. It also led to the formation of the grand mountain ranges, like Cordillera and Andes. The continents were drifting from the poles to the Equator. As a result, Europe and Africa collided. It also resulted in the formation of the Atlas Mountains in Africa and the Alps, the Carpathians and the Dinaric Alps in Europe. The collision of Europe with Asia resulted in the formation of the Himalayas (Yount, 2009).

Wegener realized that he needed a great number of evidence to convince the other researchers. Wegener used his notes made during expeditions to provide the evidence. He also considered them indirect. Evidence was useful for his hypothesis, but did not prove it.

All the attempts to explain the continental movements by the inertial forces generated on the surface of the rotating body and the gravity of the Moon were immediately rejected by the scientific community of that time. Scholars were skeptical about the theory and considered Wegener an outsider. Several decades the hypothesis regarding the continental horizontal shifts was considered a fantasy. Fortunately, in the late 60s it was officially approved and accepted after the seafloor spreading studies (Drake, 1976).

Nowadays, Plate tectonics is a theory that studies the movement of the Earth’s lithosphere. According to the theory, the lithosphere is divided into several tectonic plates. These plates are from 100 to 120 kilometers thick. Plates are located on the soft mantle layer. It is also called asthenosphere. Scholars distinguished from seven to eight main plates. They were named in accordance with their location. For instance, there are Pacific, Antarctic, African, Eurasian, Indo-Australian, North-American and South-American Plates. Furthermore, there are several dozens of middle sized plates and a large number of small plates. Furthermore, the plates are constantly moving; annually, their location changes from zero to 100 mm (Read & Watson, 1975, pp.13-15).

Scholars also distinguished several types of boundaries, such as convergent, divergent and transformational. The convergent zone occurs when two plates meet with one another and collide. Often, tectonic plates consist of the same oceanic crust. As a result, the denser plate moves underneath the thinner one causing its destruction. It results in the formation of volcanoes and mountain ranges in these regions. Divergent boundaries occur when the plates start drifting apart forming emptiness. The gap may be covered with new crustal material made of molten magma. It cases gigantic rift valleys on the land and mid-oceanic ridges underwater. Transformational boundaries occur when plates glide against each other. It may happen on the continent or underwater. This causes the release of huge energy resulting in constant earthquakes as well as tsunamis (GNS Science, n.d.).

Thus, Alfred Wegener has made a great contribution to the understanding of the planet. Before his discoveries, scientists could hardly provide any substantial reason for such natural processes as emergence of volcanoes, earthquakes, tsunamis etc. Wegener’s “Continental Drift” theory caused strong discussion and critics. For a long time, the theory has been rejected by the majority of the scientific society. However, in the beginning of the 20^th century, the situation has changed greatly as the number of scientific findings proved the credibility for the theory. Wegener’s work was based on the assumptions of other scholars like Alexander Ortelius, Alexander von Humboldt and Antonio snider-Pellegrini who had noticed that all continents greatly fit one another. Wegener officially announced that, millions of years ago, there was only one Pangaea continent, which was divided apart in the course of time. Nowadays, based on Wegener’s theory, scientists have proved that there are several major plates, which are constantly drifting. These plates could approach each other as well as move apart causing different natural phenomena. Plates are located on the hot mantle. Cooling down, mantle starts to move the Earth’s surface. When the plates collide, they form all kinds of mountain ranges, such as the Himalayas or the Appalachian mountains. They may also spread apart forming various valleys like the one that goes through the eastern Africa. The earthquakes and volcanic eruptions are usual phenomena in such regions. Moreover, plates may even slide against each other causing constant earthquakes. Nowadays, scientists, based on the knowledge from the “Continental Drift” theory by Alfred Wegener, are able to explain all these natural processes.