Transcript of Continental Drift.
By: Lauren Noga Continental Drift Theory. Alfred Wegener In 1910, Wegener discovered that the Atlantic coastlines looked as if they could fit together. He began to speak about this idea in 1912 when he had come up witht the idea of "Continental Displacement." Which later, was renamed "Continental Drift." http://www.ucmp.berkeley.edu Sources. Alfred earned a Ph.D in Astronomy and also started to get interested in different fields of meteorology. Wegener also read a book that showed pictures of fossils of identical plants and animals located on opposite sides of the Atlantic. So, not only did the two sides look as if they could fit together, there were fossils located there, as well. He showed that the Appalachian Mountains matched the Scottish Highlands. Therefor, they would've had to be connected at some point. Fossils of tropical plants were found in places today with an utterly different climate than what the plants would've lived in. Due to his evidence and studies, Wegener decided that the continents had been one single mass, Pangaea. After millions of years, the land masses separated from each other to form there present day shapes and locations. Wegener served in World War 1 and was wounded twice. Even with his injuries, he published his ideas 1915. Although some scientists supported his idea, most didn't. http://www.pbs.org Although Alfred had different evidence to support his theory, he lacked a description of the forces that would've been able to move the continents. That was the reason many scientists didn't go along with his studies. Evidence http://www.nndb.com Missing Evidence. Plate Boundaries. www.platetectonics.com The three types of plate boundaries are Divergent boundaries, Convergent boundaries, and Transform boundaries. Divergent. At a Divergent boundary, the two landmasses pull apart from each other. Over time, the land will split apart, creating space between each other. An example of a divergent boundary would be the Mid Atlantic Ridge. Convergent. At a convergent boundary, the land dives under another piece of land. Causing the land to be recycled under the interior. An example of a convergent boundary would be Himalayas. Transform. At a transform boundary, the two plates slide horizontally past each other. These types of boundaries are more commonly known as faults. An example of a transform boundary would be the San Andreas Fault. Layers of the Earth. If you were to cut the Earth in half, you could see all of the different layers inside of it. In the very middle is the inner core. Which is also referred to as the solid core, as it is made up of solid metals. The second layer is called the outer core, also known as the liquid core. This part of the core, rotates around as the Earth does, creating the magnetic field. Together, these two layers are about 2,200 miles thick and extremely hot. The next layer is called the mantle. It is about 1,800 miles thick and partly solid. Even though it is much cooler than the core, some of the material inside of it is molten. The last layer is called the crust. It is the uppermost part of the mantle, which means it is the coolest layer. Since it is the coolest, it is also the most solid. Scientists also call this layer the lithosphere. It floats on the melted rock of the mantle, allowing the broken pieces, or plates, to move. Even though we cannot feel the crust moving, it is constantly in motion- carrying the oceans and continents, as it floats on that molten material of the mantle. http://www.sio.ucsd.edu Scientists began to take rock samples as evidence for the Continental Drift Theory. They found that the rocks' ages increased as the distance from the divergent boundary increased. This was highly supporting the idea of sea floor spreading, which had a lot to do with Continental Drift. Creation and Destruction of Land The closer in distance rocks were away from the boundary, the closer in age they were. Therefor, this told scientists that there had to be some sort of creation of the land around that boundary. http://science.jrank.orgFull transcript