Thursday, June 6

The Crust of the Earth

Introduction to crust of earth:

In the ancient time when the earth was formed it was very cold. This earth is called as the primitive earth. As more and more planetesimals collided with the primitive earth and stuck to it, their kinetic energy got converted into heat. Radioactive disintegration of the elements, such as Uranium, Thorium etc and contraction of earth due to gravitational force also heated the primitive earth. This heating of primitive earth gradually raises its temperature and the primitive earth melted. The molten material of the earth then began to reorganize into layered structure under the influence of gravity. During the formation of layered structure the lighter molten rose up to the surface to make the earth’s crust.

Description on crust of the earth:

There are three major layers of earth out of which the uppermost layer is called the crust of the earth. The thickness of the crust of earth varies from place to place. It lies between 35 km to 60 km under continents and about 10 km under oceans. The ocean crust is different from the continental crust. The ocean crust is made up of basalt, diabase and gabbro. The continental and the ocean crust float on the second layer of earth called mantle.   The crust of the earth generally composed of lighter elements. About 75% of the earth’s crust is covered with water. The crust of the earth is composed of igneous, metamorphic and sedimentary rocks. The crust of the earth occupies the earth’s volume by less than 1%. The average density for the upper crust lies between 2.7 gram per cubic centimeter and 2.74 gram per cubic centimeter. The average density of the lower crust lies between 3.0 gram per cubic centimeter and 3.25 gram per cubic centimeter. The temperature of the crust of the earth increases with the depth. The temperature of the crust of the earth lies between 200° C to 400° C.  The temperature of the earth’s crust increases by 30° C for every kilometer

Understanding specific heat equation is always challenging for me but thanks to all science help websites to help me out.

Conclusion on crust of the earth:

Most of the rocks in the crust of the earth formed before 2.5 billion years ago. The interior crust of the earth makes up lithosphere. The lithosphere is converted into tectonic plates.

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