Continental Drift, the theory that continents move slowly about the earth's surface, changing their positions relative to one another and to the poles of the earth. In the past the theory has been discussed but not generally accepted, most geologists believing the continents to be fixed in place and subject only to vertical movements, such as those observed during mountain uplift. In recent years, however, a sound body of evidence in support of a modified form of the drift theory has been found. Ideas are becoming precise and unified, with emphasis on a moving, evolving ocean floor. The new theory is called plate tectonics.
Soon after the Atlantic Ocean had been mapped, about three hundred years ago, it was noticed that the opposite coasts had similar shapes, but it was not until the middle of the 19th century that accurate maps were published demonstrating that the two coasts could be fitted together quite closely. Some geologists then suggested that the fit of the coasts was not an accident--that the continents were once joined and had subsequently drifted apart. None of the suggestions were taken seriously.
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. He pointed out that where great ice sheets have melted in recent geological times in Scandinavia and North America, the land is rising as fast as a centimeter a year. This vertical uplift, he said, requires horizontal inflow of matter below and implies that flow and motion do take place within the earth.
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Although Wegener and Du Toit proposed that the primitive continents began to break up about 200 million years ago, there is much evidence that drift began long before then, and that continental blocks have slowly been moving about the earth's surface throughout much of geological time. It seems that before the continents drifted apart and opened up the Atlantic, they had drifted together and closed up an earlier ocean. Another place where continents seem to have bumped into each other and piled up mountains between them is the Himalayas, which may have been produced when the Indian Peninsula detached itself from Gondwanaland and gradually drifted into Asia
Bibliography
 Daley, Robert B. 1986 A study of a changing planet; CEBCO Publishing co. p.418
 Bartolini, Annachiara and Larson, Roger L; 2001 Pacific microplate and the Pangea supercontinent in the Early to Middle Jurassic; Geology, Aug2001, Vol. 29 Issue 8, p735-39
 Anderson, Don L 2001. Top-Down Tectonics; Science, 9/14/2001, Vol. 293 Issue 5537, p2016-18
 http://www.geo.cornell.edu/geology/classes/Geo101/101week6_s01.html
A significant portion of New England was formed as a result of an accretionary orogen. Southeastern New England is marked by a series of terranes that accreted onto the Laurentian supercontinent during the Silurian and Devonian. The Terranes of Gander, Nashoba, Avalon, and Meguma are present from west to east in eastern Massachusetts and all of are Gondwanan provenance. Their modern-day juxtaposition suggests that the marginal Gondwanan micro-continents collided sequentially from west to east, expanding the Laurentian continent with each respective collision. As each subsequent plate collided, an intervening subduction zone died and a new subduction zone was created to the east. The oblique collision of the Avalon Terrane into Laurentia followed the accretions of the Gander and Nashoba Terranes and preceded the accretion of Meguma. The collision was marked by uplift, mylonitic metamorphism, and calc-alkaline Nashoba plutonism as the Iapetus Ocean subducted under the Nashoba and eventually the Avalon collided obliquely into the continental margin.
15. The pictures above show how the continents on Earth’s surface have changed position over a very long period of time. What explains this change? (S6E5e, f)
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
The Franciscan Terrane of central California represents an accretionary complex formed by long-term subduction of an oceanic plate under the Western margin of the North American craton. The Franciscan complex is composed of three distinguishable belts: the eastern belt (Yolla Bolly and Pickett Peak terranes), the central belt, and the coastal belt. Age and metamorphic grade of the belts decreases to the west (Blake and Jones, 1981). Formation of the accretionary complex began during the late Jurassic in the eastern belt and has continued into the Miocene along the western coastal belt. The complex trends NNW and is bounded by the San Andreas Fault to the east and by the coastal range fault to the west. The coast range fault separates the Franciscan complex with the partly coeval Great Valley sequence. Debate exists over the tectonic evolution of the Franciscan, centered around the geographic origin of the Franciscan rock units.
“The Atlantic World was a world Europeans, Africans, and Americans “made together” –together with peoples from without.” Such is the belief of Peter Coclanis, Albert R. Newsome Professor of History and Economics and Associate Provost for International Affairs at the University of North Carolina at Chapel Hill. In his paper: Atlantic World or Atlantic/World? published in the William and Mary Quarterly in 2006, Coclanis argues that the study of Atlantic history is too narrow. He writes in this paper that there is no context in which the Atlantic world can be completely separated from the interactions with the rest of the world. The argument Coclanis believes if one is to study Atlantic history of the early modern period (circa 1500-1800 CE) one needs to focus more on other areas, such as the countries outside the Atlantic or their trading circuits in order to fully understand the history of the Atlantic. This idea that Atlantic historians need to change their focus is contradictory to what Atlantic history is. If Atlantic historians shifted their focus to include countries not connected to the Atlantic, can it still be called Atlantic history or if one was to believe what Coclanis suggests: should historians even focus on the Atlantic world at all?
Our understanding of the Earth’s interior has been a focus for scientific study for multiple decades, recognised in the early 1900’s. Throughout the years, scientists have debated and quarreled over their findings, observations and theories for the most correct model of the composition and internal structure of the Earth.
analysis on how the Atlantic became known as the Atlantic because of the presence of
To set the stage, we must go back 270 million years ago when a majority of the earth’s land masses were collected together in a single continent, a supercontinent, named Pangaea (Encyclopedia Britannica, 1). Historian Alfred Crosby explained that this collected all of earth’s land based biology into a single place, creating a single Darwinian “arena for competition” (Crosby, 1). Or in other words, one big evolutionary pot. Crosby also explains that 180 million years ago, Pangea split into two major land masses, what is now the Americas in the Western Hemisphere as one land mass and Euro-Asia and Africa as the second lass mass (Crosby, 1). What was once a single evolutionary pot, was now two, allowing for plant and animal life to take different evolutionary paths. These two worlds remained relatively separate from each other until the arrival of Christopher Columbus and other European explorers. That contact between the old world and the new world brought two distinct evolutionary arenas crashing into each other and returned a majority of the earth’s landmass into a single Darwinian pot, (Crosby, 1) This was Crosby’s re-knitting of the torn “seams of Pangaea.”
During the Late Cretaceous a period of mountain building occurred along the west coast of North America. This is called the Laramide orogeny that started the Rocky Mountains growth about seventy-five million years ago. The Laramide orogeny was different from orogenies that had happened before hand. What caused the Laramide Orogeny is uncertain but there are many theories about what caused it. One big thing to better understand the Laramide orogeny is the theory of Uniformitarianism.
About 20 million years ago the last part of the Farallon sea floor plate subducted under the North American plate. This put the North American plate and the Pacific plate into contact, but unlike the Farallon sea floor plate, the Pacific plate sheared against the side of the North American plate. Because there was no plate subducting, the North American plate was in direct contact with the mantle (Tierney, 29). Heat from the mantle made the continental crust more ductile, which allowed the crust to extend and thin.
How did the Atlantic System affect Europe, Africa, and the Americas? (The Earth and Its Peoples, 500)
839-841). Hoboken, NJ: Wiley & Co., Inc. Kerzner, H. (2013). The 'Path of the Earth'. Journal of Science, 63(3), pp. 113-117.
"Changing Sun, Changing Climate." Changing Sun, Changing Climate. N.p., Feb. 2014. Web. 27 Mar. 2014.
The Permian Period was the last period of the Paleozoic Era. During this geological time period’s earlier stages glaciation was extensive. Middle Permian began to warm, and by the late Permian the environment was hot and dry. The environmental conditions were so extreme that the marine and terrestrial life forms were greatly affected. According to research the drastic climate change could have been caused by the formation of Pangaea. In 1912 Alfred Wegener while studying his theory of the continental drift, discovered Pangaea’s very existence. A combination of all of Earth’s landmasses joined together and covered 1/3 of Earth’s surface. Pangaea was f...
Divergent boundaries are when the plates move apart from each other. And lastly, Transform boundaries are when the plates slide laterally past each other.for some examples: Southern California is on the boundary of the North American Plate and the Pacific Plate, therefore making it an easy fault zone. That is why Southern California has so many earthquakes. It is because they are on the a transform boundary. Another examples is that A divergent boundary on iceland between the North American plate and the Eurasian plate is causing iceland to split along a mid ocean