The mantle is the broadest layer of the earth at 2900km thick; it makes up about 85% of the Earth’s weight. It is between the Earth’s outer layer, the crust, and the super-heated outer core.
The mantle is made up of a semi-molten rock called magma. The mantle can be split into two different sections: the lower mantle, made from a more solid rock, which is hot enough to melt but stays solid due to the pressure pushing onto it.
The other half consists of the upper mantle, made from solid and liquid rock that can move, causing pressure underneath the crust. This pressure can sometimes cause the mantle to leak out onto the surface of the Earth – this is called a volcano!
The Structure of the Earth
The Earth has four main sections: an inner core, an outer core, a mantle, and an outer crust.
- The Inner Core is a giant metal ball made mainly from iron and has a temperature of 5000°C – 6000°C.
- The Outer Core is a liquid layer of iron and nickel that flows around the Earth’s center, creating its magnetic field.
- Mantle – this is split into the lower and upper mantle.
- The Outer Crust is the thin outer layer of the Earth, made up of granite, sedimentary rocks, and metamorphic rocks, otherwise known as tectonic plates.
History of the Structure of Earth
Inge Lehmann discovered what lies in the center of the Earth, a solid core surrounded by molten liquid rock.
Before her discovery, other scientists thought that the Earth’s core was liquid too, but Igne’s ideas explained the strange readings from earthquake waves.
The Earth’s core is solid because of the pressure from the Earth’s outer layers pushing down on it.
