Layers of Earth

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By: - Nikhil Rungta

Layers of the earth : 

Layers of the earth Earth consists of four major layers they are; Crust Mantle Outer Core Inner Core

Crust : 

Crust This is the layer that we live on. The crust is 3 – 5 miles thick. The thickness ranges from 5 thick miles under the oceans to 25 miles thick under the continents. It is the thinnest layer of the earth. The temp. of the deepest part of the crust is 1600oF (870oC). The crust is composed of two rocks; granite and basalt. It is also known as SiAl (Silicon & Aluminium).

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Earth’s crust is divided into several plates that moves in 3 ways. 1. Convergent Movement 2. Divergent Movement 3. Conservative Movement/Plate

Continental Crust : 

Continental Crust Continental Crust: The crust under the continents Thicker than oceanic crust, 20-45 miles thick Composed of mostly granite Older than oceanic crust Density is 2.7 g/cm3

Oceanic Crust : 

Oceanic Crust Oceanic Crust: Crust under the oceans. Thinner than continental crust, 4-7 miles thick. Composed mostly of basalt. Younger than continental crust. Density is 3 g/cm3. Basalt is much denser than the granite. Because of this the less dense continents ride on the denser oceanic plates.

Mantle : 

Mantle This layer is semi liquid It consists of magnesium, iron, and silicon Width – 3000 Km. It is more solid closer to the surface The mantle is composed of hot iron-rich silicate rocks. Flow in the mantle occurs as convection currents; hot material in the mantle rises, cools and then sinks. Mantle is elastic which means it behave in plastic manner. Thickness – 1800 miles

Outer Core : 

Outer Core Thickness – 1400 miles. This is consists of liquid due to the high temperatures like 4000oF – 9000oF. It is located 1800 miles beneath the crust. This layer consists of nickel and iron and is better known as NiFe{Nickel & Ferrous(Iron)}. Because less weight is exerted on the outer core, the pressure is less there, so iron and nickel present here are in liquid state.

Inner Core : 

Inner Core This layer is solid. Pressure – 45000000 pounds/sq.inch, Inner Core’s pressure is 3000000 million greater than the sea level. It consists of the metals nickel and iron and is also better known with the name of NiFe. Its temperature is 9,000 degree Fahrenheit. It is 800miles thicker, 4000 miles beneath the crust. The core is composed mainly of iron and nickel. In the inner core, iron and nickel are solid. Although the inner core is very hot, pressure from the weight of the rest of the Earth doesn’t allowed the material to melt.

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Lithosphere The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. The crust of the Earth is broken into many pieces called lithospheric plates. The plates "float" on the soft, semi-rigid Asthenosphere.

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Asthenosphere Asthenosphere is made up of asphalt which has a coal tar like consistency . It is located below the lithosphere. It is made of Silicon and magnesium which is very denser, that’s why it is better known as SiMa. SiAl that is the crust floats on SiMa. It is the part of the mantle that flows and moves the plates of the earth.

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Thank You