Plate Tectonics

By Tony Angelini

What are Plate Tectonics

Plate tectonics is the theory that Earth's top layer is divided into several plates that glide over the mantle. The theory of Plate Tectonics was founded in the 1950's the theory was first proposed by scientist Alfred Wegener in 1912. Wegener didn't have an explanation for how continents could move around the planet, but researchers do now because, one all the continents fit together like a puzzle, and two Fossil Evidence, the same fossils and species of animals found near the coastlines.

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The Four Layers of The Earth

The four layers are the Crust, Mantle, Outer Core, Inner Core. The Crust is the first layer of the Earth which is the thinnest layer. The crust is split into two parts the continental crust, and the oceanic crust.The continental is made up of igneous rocks, and the oceanic crust is made up of sedimentary and basalt rocks. The mantle is the second layer of the earth. It is split up into two different parts, the lithosphere (which is the top part) and the asthenosphere (which is the bottom part). The Outer Core is made up of iron and nickel. The temperature of the outer core is around 4400 degrees.
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Sea-floor Spreading

Sea-floor spreading is a process that occurs at mid-ocean ridges. New oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Harry Hess discovered Sea-floor spreading. Sea- floor spreading helps explain the continental drift because seafloor spreading is caused by two plates moving apart. Its caused by plate tectonics. Continental drift also is caused by plate tectonics.
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Convection helps with plate movement because the convection currents move the lithosphere and the crust slightly.

Types Of Boundaries

Their are four different types of boundaries, Transform, Divergent, Convergent, and Convergent with subduction. The transform boundary slip slides causing earthquakes . An example would be the san Andrea's fault. The divergent boundary are two plates spreading apart from each other causing earthquakes, volcanoes, and sea-floor spreading. An example would be The Atlantic Ridge. Their are two types of convergent boundaries. The first one deals with two continental plates that collide together forming mountains, the second boundary forms when a oceanic plate collides with a continental plate forming a trench or volcano. An Example would be the rocky mtn. or the Marianas Trench.
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Ring of Fire

No! Its not the song by Johnny Cash. The Ring of Fire is an area Located in the Pacific Ocean were their is a lot of volcanic and earthquake activity. The Ring of Fire is a direct result of plate tectonics and the movement and collisions of lithosphere plates.
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