The mantle is the largest of the geological layers that make up the Earth. It is found beneath the crust and is about 1,800 miles thick. Surrounding the core, the mantle makes up about 84 percent of the volume of the Earth.Continue Reading
The mantle is made up of mafic and ultramafic rock. These are rocks made largely of iron and magnesium, and mafic is a portmanteau of the words "magnesium" and "ferric." The rock in the mantle is very hot and can be viscous or molten depending on the temperature and the pressure.
The mantle is divided into two zones. The upper mantle contains the lithosphere and the asthenosphere beneath it. The rocks in the lithosphere are mostly rigid, while the rocks in the asthenosphere are more plastic.
There is a transition zone between the upper and lower mantle and a boundary between the lower mantle and the core. The thickness of this boundary can vary.
There is also a boundary between the crust and the mantle called the Mohorovičić discontinuity or the Moho. Despite decades of effort, geologists still have not drilled all the way to the Moho. It is about 3 miles beneath the crust at its shallowest point.Learn more about Layers of the Earth
The four layers of the Earth are called the inner core, the outer core, the mantle and the crust. In addition, there are two different types of crust. The continental crust is the part that is under land, and the oceanic crust is the part under the oceans.Full Answer >
The heat that is present in Earth's mantle is made up of leftover heat from when the planet was formed, latent heat from the Earth's inner core and heat produced by the decay of radioactive isotopes. The majority of the heat is caused by the decay of isotopes such as potassium 40 and uranium 238.Full Answer >
Convection currents in Earth's mantle are caused by the rise of hot material rising towards the crust, becoming cooler and sinking back down. This process occurs repeatedly, causing the currents to constantly flow. The movement of the currents plays a factor in the movement of the mantle.Full Answer >
The key characteristics of the Earth's layers are the thinness of the crust, the rigidity of the upper mantle and the viscosity of the lower mantle and the asthenosphere. Other characteristics are the liquid state of the outer core, and the great heat and pressure of the inner core.Full Answer >