Return to Geology Index pageInterior of the Earth
The Earth's interior consists of five distinct layers. These layers include the crust, moho, mantle, outer core and inner core.
The Crust is the layer in which we live on. It contains all the material which supports life on Earth. It is made up of eight major elements. Oxygen and Silicon make up approximately 75% of the crust elements. The crust varies in thickness from 4.8km to 56km or 3 to 35 miles in thickness. The crust is at its thinnest in the ocean trenches and the thickest under mountain ranges.
The Moho is apart of the upper mantle which acts as a transition zone between the crust and the mantle. The moho acts like a liquid plastic type substance which allows the crust to move on top of the mantle. The Moho's thickest varies from place to place in the world.
The Mantle is the thickest layer of the interior of the Earth. It is 2,898km or 1,800 miles thick. The mantle is made up of the minerals olivine, peridotite and eclogite. The mantle acts as insulator protecting the crust from the extreme heat of the core. The temperatures in the mantle range from 1,000 C to 2,800 C.
The Outer Core is liquid Iron and Nickel. The outer core is 2,200km or 1,376 miles thick. The temperature ranges between 2,500 C to 3,500 C.
The Inner Core is made up of solid Iron and Nickel. It is 1,216km or 756 miles thick. The temperature is 4,000+ C! The inner core is solid due to the extreme pressure which exceeds 6,000,000 atmospheres!