In 1912, however, the German meteorologist Alfred Wegener investigated the fit of the Atlantic coasts more carefully than had his predecessors and grouped all the continents together into one great land mass, which he called Pangaea. He supposed that the mass began to break apart about 200 million years ago. He also showed that some geological features on the opposite coasts could have fitted together, and that there were many striking similarities between the fossil plants and reptiles on the opposite coasts, particularly the coasts of Africa and South America. If the continents were pushed together, the geological, fossil, and other lines of evidence would join together accurately in the way that lines of print on a torn newspaper would join when the paper was reassembled. Wegener also pointed out that ancient climatic zones seemed to have lain in different places from the present zones.
Investigation of the Polar Dinosaur Today we know through the evidence of fossils that dinosaur and other large reptiles once lived on every continent on earth. If you were a paleontologist in charge of finding fossils where would you look first? In the search for evidence the icy continent of Antarctica would be perhaps the last continent you would think to search. However, during the last twenty years a remarkable number of prehistoric fossils have been found in regions close to the South Pole. Beginning in 1960 with an expedition lead by a man named Spitzbergen, fossilized footprints from non-avian dinosaur showed the region once had a drastically different climate.
In 1915 Alfred Wegener who was a German geologist discovered identical fossils of plants and animals on different sides of the Atlantic. This led Wegener to believe that the continents were once connected. After Wegener’s findings scientists showed that plate tectonics caused continental drift which led to evolution of species. Figure 1.2 showing fossil remains found by Alfred Wegener Biogeographers were now able to identify that when the continents have a collision species are able to mix and then when the continents then separate they take their species with them. For example Africa, South America, Australia and New Zealand were part of Gondwanaland.
During this time, Virginia was 15' to 30' of the equator. Scientist wanted to know why ice was on the equator during the Neoproterozoic era. (Monastersky,1998) The team of scientists consisted of a biogeologist, geochemist, and tectonic geologist with the common goal of understanding the coevolution of life and environ... ... middle of paper ... ...excursions a record of gas hydrate destabilization following Earths coldest intervals? Geology 286-287 Hoffman, Paul F.; Schrag, Daniel P. "Snowball Earth" Scientific America 21 Jan 2000 Scientific American Online. Online 31 Mar 2003 Kennedy, Martin J.; Christie - Blick, Nicholas; Prave, Anthony R. (2001) Carbon isotopic composition of Neoproterozoic glacial carbonates as a test of paleoceanographic models for Snowball Earth phenomena.
Briefly speaking, the formation of the Rockies transpired from hundreds and millions of years of uplift by tectonic plates and millions of years of erosion and ice have helped sculpt the mountains to be what we see today. The majority of the rocks that make up the Rocky Mountains began as simple shale, siltstone, and sandstone accompanied by smaller amounts of volcanic rock which formally built up for approximately 1.8 to 2 billion years in the ancient sea. By 1.7 to 1.6 billion years, these sedimentary rocks got caught in the zone of collision between parts of the earth’s crust and its tectonic plates. The incredible heat at the core of the mountain range then recrystallized the rock into metamorphic rock by the heat and pressure of the collision forces. Eventually, the shale would be transformed into both schist and gneiss.
(Rejoined continents [This Dynamic Earth, USGS].) Not only fossil proves this theory, but also same living animals are found on two different continents. Furthermore, Wegener found out that same rocks and mountain ranges begin on one continent, and end at one coastline; but on another continent cross the ocean, there are similar rocks and mountain ranges appear. For instance, people found rocks with same types and rocks in Greenland, Ireland, Scotland, and Norway which are places really far away from each other. Last but not least, base on climatic evidence, scientists later pointed out that there are glacial striations in South America, Africa, Madagascar, Arabia, India, Anta... ... middle of paper ... ... at hot spots rather than plate boundaries.
He was a Scottish lawyer, a geologist as well as a supporter of Uniformitarianism. He was the author of Principles of Geology. His theory was that earth must be very old and that throughout time the planet has undergone processes that change the shape the land. That includes erosion, earthquakes, glacial movements, volcanoes, and the decomposition of dead plants and animals. (Port, 2006) Thomas Robert Malthus was born on February 13th, 1766, at Dorking, a town south of London.
Sediment was deposited here layer upon layer and eventually the layers were cut through by the Colorado River. The time covered by the layers of rock in the Grand Canyon represent about two billion years of earths history. The next chapter introduces to us how life began. Many scientists believe that life began as soon as the earth cooled sufficiently after just forming. It is believed that the first life on earth emerged some four billion years ago.
In the nineteen-teens, as World War I raged across Europe, Milutin Milankovic, a Serbian astronomer and prisoner of war, was busy computing the gravitational force of planets like Jupiter on the Earth’s tilt and orbit. He had an idea that the amount of solar radiation that reaches higher latitudes could trigger an ice age or warm up the Earth. He believed that slow changes in the Earth’s orbit contributed to the amount of solar radiation reaching a particular latitude. By the end of the war, his first paper was published on the subject, and he began to expand upon his initial ideas. In 1941, he published Canon of Insolation of the Earth and Its Application to the Problem of the Ice Ages, describing his theories about the Earth’s orbit and tilt which are now referred to as the Milankovitch Cycles.
In 1915, Alfred Wegener proposed the theory of continental drift to explain the past and present location of the continents; however, his ideas were met with resistance because he could not provide evidence that would support his hypothesis. Later oceanographers, geologists, and scientists collected more information to verify and explain the theory. In the 1960s, the mechanism and processes were explained by plate tectonic theory. With advancements in science and technology, scientists are still collecting more information. Answer each of the following questions in your own words and in 3–5 sentences: 1.