Structure Of The Earth

The interior of the earth can be divided into 3 different layers – crust, mantle, and core. The crust is the outermost layer of the earth, and the core is the innermost layer of the earth, located at a depth of 2900 Km. This article briefly throws light on these 3 different interior layers of the earth.

Structure of the Earth

• The Crust
• The Mantle
• The Core

The Crust

• The crust is the outermost solid part of the earth.
• It is fragile.
• The thickness of the crust varies under the oceanic and continental areas.
• Oceanic crust is thinner as compared to the continental crust.
• The continental crust is thicker in the areas of major mountain systems.
• The crust is made up of heavier rocks having a density of 3 g/cm3.
• The kind of rock seen in the oceanic crust is basalt.
• The mean density of material in the oceanic crust is 2.7 g/cm3.
• Silica (Si) and Aluminium (Al) are major constituent minerals. Hence it is often termed as SIAL. Also, sometimes SIAL is used to refer to the Lithosphere.

The Mantle

• The portion of the interior beyond the crust is called the mantle.
• It is in a solid-state.
• It has a density higher than the crust portion.
• The thickness ranges from 10-200 km.
• The mantle extends from Moho’s discontinuity to a depth of 2,900 km.
• The asthenosphere is the upper portion of Mantle.
• It is the chief source of magma that finds its way to the surface during volcanic eruptions.
• The crust and the uppermost part of the mantle are called the lithosphere.
• The major constituent elements of the mantle are Silicon and Magnesium and hence it is also termed as SIMA

The Core

• The core-mantle boundary is positioned at the depth of 2,900 km.
• The inner core is in the solid-state whereas the outer core is in the liquid state.
• The core is made up of very heavy material mostly constituted by nickel and iron. Hence it is also called the “nife” layer.