Comparing Seafloor Spreading And Plate Tectonics

There are three different types of plate boundaries. The first type of plate boundaries is, the spreading boundary. A spreading boundary is when two plates move apart. The spreading boundary is also known as a divergent boundary. The second type of plate boundary is a colliding boundary. A colliding boundary is when two plates come together, or collide. It is also known as convergent boundary. The third is, a sliding boundary. A sliding boundary is when two plates slip past each other moving in opposite directions. It is also known as transform boundary. Those were the three different types of plate

Overall the plate tectonics theory does seem valid as there is lots of evidence to prove it right. For example fossils on either side of the ocean, climates being the same in different continents and hot spots. But there are some stronger pieces of evidence like the ring of

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.

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

2. The theory of “Pangaea” exists suggesting that the continents were once nestled together into one mega-continent. The continents then spread out as drifting islands.

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.

Seafloor spreading when new oceanic crust is being created where two tectonic plates are diverging from one another. One of the largest examples of this is the East African Rift Valley. “In simple terms, a rift can be thought of as a fracture in the earth 's surface that widens over time, or more technically, as an elongate basin bounded by opposed steeply dipping normal faults” (geology.com). The East African Rift is a 3000 km long feature that began developing millions of years ago. The rift travels up through the lakes on the eastern side of Africa up towards the Arabian Peninsula and down through Mozambique and Zimbabwe(britannica.com). It is “the southern part of the Great Rift Valley, one of the most tectonically active regions in

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

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

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:

Explain the Theory of Plate Tectonics. The theory of plate tectonics is that plate tectonics is what moved pangea, a supercontinent with all the continents combined away from each other.

The breaking apart of this supercontinent was due to the movement of the Earth's Tectonic Plates. Tectonic Plates are large masses of the lithosphere or outer layer of the Earth's surface. The layers included in the Lithosphere are the Crust up to the upper layer of the Mantle. The Oceanic Crust is thinner and denser than the Continental Crust and can be found underneath the ocean. It is also more active than the Continental Crust that stretches 200 km below the Earth's surface. This crust drifts and moves either horizontally or vertically causing geological phenomenons such as earthquakes, volcanic eruptions, etc. The major tectonic plates are North American, Caribbean, South American, Scotia, Antarctic, Eurasian, Arabian, African, Indian, Philippine, Australian, Pacific, Juan de Fuca, Cocos, and Nazca. These plates move an estimate of 1 to 10 cm per year causing interaction at plate boundaries. When two plates are colliding or moving toward each other it is in Convergent boundaries. If these two plates are Oceanic Crusts, they are in Subduction zones wherein the denser plate in forced beneath the less dense plate and would eventually melt or destroy. On the other hand, when two plates move away from each other it is in Divergent boundaries. New crust material from molten magma formed below may fill the space between these plates or become ocean basins.

The three major types of tectonic plates are divergent, subduction and transform. Divergent plates tend to move apart from each other. Subduction plates are when oceanic plate moves under a continental plate. This can cause volcanos to erupt and large sized earthquakes. Transform plates slide back and forth against one another. The Lithosphere consists of the Earths crust and uppermost mantle. The North American plate and the South American plate are the major plates of the lithosphere. The lithosphere also consists of the Pacific plate, the African plate and the Eurasian plate. The Pacific plate is the only major plate that is mainly underwater and is also the largest plate in the lithosphere. The Earth was once one large continental body called Pangea, before the plates started

7. What is the relationship between plate tectonics and the ocean floor—seafloor spreading, for example?

In the middle of the eighteenth century, James Hutton proposed a theory, uniformitarianism; “the present is the key to the past”. It held that processes such as geologic forces- gradual and catastrophic-occurring in the present were the same that operated in the past. (Matt Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered that the coasts of the eastern part of South America and the