Structure Of Earth's Interior

     STRUCTURE  OF  EARTH'S  INTERIOR

The interior of earth is divided into three parts:-

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THE  CRUST

* The crust is the outermost and the thinnest layer of the Earth. This layer has the least density and its thickness varies about 8 to 40 km.

* Thickness of the crust is more in the continents and lesser in the oceans while density of continental crust is lower than oceans.

* The rocks forming the crust of the Earth are rich in the lighter minerals like silica and aluminium. Hence the layer is also called as Sial ( silica and aluminium ) . The average density of this layer is 2.7 gm/cm^3

THE  MANTLE:-

* This layer is the intermediate layer of the Earth in terms of both its location and density.

* It is about 2900 km in thicklness composed of minerals in a semi solid state.

* It is divided into further two layer upper mantle and lower mantle. The upper part of the mantle is called the Asthenosphere, which is about 250 km thick.

* Due to presence of minerals like silica and magnesium in the rocks forming this layer of ther Earth, the mantle layer is also known as Sima (silica and magnesium)

* The transitional zone seperating the mantle from the core is called the Gutenberg Discontinuity.

THE  CORE :-

* The core is the innermost layer of the Earth and occupies its center. It is about 3500 km in radius.

* The core is further divided into two layers : outer core and inner core.

* The outer part of the core is believed to have the properties of liquid and the innermost part of the core may be called solid or crystalline.

* This layer is also known as Nife (nickel and iron) because this layer contain large concenteation of iron and nickel.

* Temperature of the core is between 2200C to 2750C.

* Average density of Earth is 5.53gm/cm^3

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