The mantle rock beneath the earth's plates is extremely hot because of the radioactive iron core that bombards it with particles, as well as the gravitational pressure at that depth. The pressure is what keeps the mantle semi-solid, not allowing it to fully melt. As a result, the mantle is constantly in motion. Plate tectonics describes the effect the mantle's motion has on the topmost crust.
Convection is another reason the mantle flows. Heat is transferred to an object by a surrounding liquid if the liquid or object is moving. If the liquid moves more quickly than the object, then the liquid transfers energy to the molecules of the object.
The lower part of the mantle is closer to the hot iron core and is warmer than the higher part. Convection causes the lower, warmer portion of the mantle to rise and the upper, cooler mantle to fall in a continuous cycle. These convection cells create the motion that slowly drives the tectonic plates around the Earth.
When there are deep fractures in the crust and upper mantle at fault lines caused by earthquakes, the hot mantle rises through the weaker rock. It forms bubbles as it rises, which further breaks the rock because bubbles expand. This melted mantle is called magma and it flows or explodes to the surface as lava.Learn More
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 Earth's mantle is 2,900 kilometers (1,802 miles) thick. The mantle lies between the core and the outer crust layer and consists of four layers: lithosphere, asthenosphere, upper mantle and lower mantle.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 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 >