Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener’s ideas by using the evidence of seafloor spreading to explain what moved continents. The theory of plate tectonics is what brings together continental drift and seafloor spreading. Plates are made of lithosphere topped with oceanic and/or continental crust. The plates are moved around on Earth's surface by seafloor spreading. convection in the mantle drives seafloor spreading. Oceanic crust is created at mid-ocean ridges. The crust moves outward from the ridge over time. The crust may eventually sink into the mantle and be
James Hutton was the first scientist to address the Earth was millions of years old, as well as alive and is continuously being formed. Charles Lyell popularized uniformitarianism, and believed the Earth was being shaped by slow moving forces. Alfred Wegener introduced the foundation for the theory of continental drift. Wegener was one of the first to recognize and have an understanding of how the Earth works which required data and information from earth sciences. In the 1960s, the theory for the continental drift became known as the theory of plate tectonics or plate building.
II: Plate tectonics shows the features and movement of the Earth. The theory of plate tectonics says that the outer shell of the earth is broken down into pieces often called plates (Korenaga). These plates hover over the mantle creating movement (Marshak). With plate tectonics you can determine the earth’s features without actually seeing it.
If new crust is indeed being produced at the rifts, where does the additional older crust go?
The theory of plate tectonics was first developed by Alfred Wegener. He concluded that the continents seem to have a similar shape and could potentially fit together. This suggested that they were at one time joined together as part of 2 super continents called Gondwanaland and Laurasia was in the north. This theory was said to be proven by the discovery of fossilised remains of a mesosaurus that were found on the coasts of Brazil and Gabon. Sea floor spreading is another theory that supports the idea of plate tectonics; this theory discovered that rock is being formed under the ocean as a new sea floor. Sea floor spreading was shown in the Atlantic, where it is believed the Eurasian and North American plates are moving apart on a
The plate tectonics theory was made by a German named Alfred Wegener. He stated that a single continent existed about 300 million years ago named Pangaea and that it split into two continents of Laurasia in the north and Gondwanaland in the south. Today’s continents were formed by further splitting of the two masses.
The Plate Tectonic Theory developed in the late 1960’s, when people noticed how continents either side of the Atlantic Ocean seemed to almost fit together. Francis Bacon, an English Philosopher was aware of this as early as 1620. Topographical and geological evidence built up and allowed Alfred Wegener to publish a theory in 1912, suggesting that the continents were once all joined together in a supercontinent he called Pangaea. Wegener proposed that at some time, the land masses had drifted apart until they occupied their current positions on the globe. There was lots of evidence to support his theory including
Continental drift was a theory offered by Alfred Wegener in 1912 that hypothesized that all the continents at one time fit together as one land mass. Wegener, explained that the ends of each continent could fit together like a puzzle and that over time the continents drifted apart. "The model explained why the same types of fossils occur in sedimentary rock on both sides of the vast Atlantic Ocean" (Star, 2008, pg. 250), in other words allopatric speciation. Wegener's theory did not have a supporting geological mechanism. Many years later and advances in technology brought about the plate tectonics theory. Essentially it says:
Plate tectonics is the scientific theory that attempts to explain the movements of the Earth's lithosphere that have formed the landscape features we see across the globe today” (Briney). Geology defines “plate” as a large slab of solid rock, and “tectonics” is part of the Greek root word for “to build.” Together the words define how the Earth’s surface is built up of moving plates. The theory of plate tectonics dictates that individual plates, broken down into large and small sections of rock, form Earth’s lithosphere. These fragmented bodies of rock move along each other atop the Earth’s liquid lower mantle to create the plate boundaries that have shaped Earth’s landscape. Plate tectonics originated from meteorologist Alfred Wegener’s theory, developed in the early 20th century. In 1912, he realized that the east coast of South America and the west coast of Africa appeared to piece together like a jigsaw puzzle. He further examined the globe and deduced that all of Earth’s continents could somehow be assembled together and proposed the idea that the continents had once been linked in a single supercontinent called Pangaea. To explain today’s position of the continents, Wegener theorized that they began to drift apart approximately 300 million years ago. This theory
Two plates can separate to split continents apart, to form new oceans, or to enlarge existing oceans by forming new crust in giant rifts in the ocean floor. Plates can converge and collide, forming chains of volcanic islands and deep trenches in the ocean, volcanic mountain belts along coasts, or giant belts of folded mountains between continental masses. These movements and their physical consequences are studied in the branch of geology called plate
To support the theory of continental drift is through topography, surveying the floors of oceans, charts of rock magnetism, and statistics on rock ages (Trefil & Hazen, 2010). At one time scientist believed that the deep ocean floors were flat; accumulating the sediment that progressively wore away from the prehistoric landmasses (Trefil & Hazen, 2010). However, they discovered steep-walled valleys and elevated highlands. This was evidences that just as the continents are transformed and are active, so to is the seafloor (Trefil & Hazen, 2010). The Mid- Atlantic Ridge, positioned in the central part of the Atlantic Ocean, is recorded to be the longest mountain range on this planet. Volcanoes, lava flow, and earthquakes are a source of
He also used an Austrian geologist’s theory that the continental crust, sial, was lighter than sima and the sial layer could move across the ocean floor (Healey, 2006, para. 15). Wegener further stated that the tides could cause the continents to move and later came to the conclusion that magma could also be responsible for the movement. Wegener made two more journeys to Greenland to conduct meteorological and geophysical studies. His final trek in 1930 included the examination of the glacial sheets to provide further evidence regarding
In the early 1900´s, Alfred Wegener developed a hypothesis called the continental drift. This hypothesis states that All continents Were once joined together in a single landmass. Over time, All continents drifted apart Called the continental drift.This Paragraph will state 4 Types of evidence why Each piece of evidence supports the claim.
After World War 2, the U.S. Office of Naval Research intensified efforts in ocean-floor mapping, leading to the discovery of the Mid-Atlantic Ridge to be part of a continous system of mid-oceanic ridges on all ocean floors, prompting Harry H. Hess to suggest the theory of sea-floor spreading. The oldest fossils found in ocean sediments were only 180 million years old and little sediment were accumulated on the ocean floor. Thus, he suggested that seafloors were no more than a few hundred million years old, significantly younger than continental land due to
Alfred Wegener was a scientist who proposed the continental drift theory. The hypothesis Wegener had been the continents were once all together, then over time they drifted apart from each other. The example Wegener used were jigsaw puzzle. If you put all the continents together, they will match exactly up such as a puzzle. Plenty of scientist did not agree with Wegener because of his evidences. Wegener gained more evidences such as similar fossils were on the edge of South America and Africa, were Wegener believed were once together.
In junior high school, I have learned the Continental Drift Theory, and my geography teacher told me there was a new theory based on the Continental Theory, i.e. Plate Tectonics. I accessed to the Internet to find the information about Plate Tectonics.