The mantle can be subdivided into the upper and lower mantle.
The uppermost part of the upper mantle is part of the lithosphere, and is sold and rigid. The lower part of the upper mantle is partially molten, and hence can flow.
The lower mantle is solid, but behaves in a plastic fashion, much like blu-tack.
The mantle is predominantly composed of an ultramafic rock called peridotite.
Further Detail:
The Earth's mantle is the largest layer of the Earth by volume accounting for around 84% of the Earth. It is approximately 2885 kilometers thick.
The Earth's mantle is composed of rocks that have higher concentrations of mafic minerals (containing iron and magnesium) and lower in concentrations of the felsic minerals (aluminum and silica) than the rocks of Earth's crust.
The concentrations of the above elements therefore mean that the Earth's mantle is composed of a series of minerals that are predominately calcium / iron / magnesium aluminum silicates.
Such as:
At depths shallower than approximately 460 km, these minerals form the rocks types Peridotite, Dunite (Olivine-rich Peridotite), and Eclogite.
At depths greater than 410 km Olivine becomes unstable and is replaced by a number of different mineral forms known as poly-morphs which are stable at higher pressures. These include Wadsleyite which forms at depths between 410 and 520 km and Ringwoodite which forms between 520 and 600 km deep.
These depths are based on a number of seismic dicontinuities at the depths of 410 km (thought to mark the transition from Olivine to Wadsleyite) and at 520 km (thought to mark the transition from Wadsleyite to Ringwoodite) respectively.
At depths greater than around 650 km these upper mantle minerals start to become unstable due to the increased pressure and the minerals below this take the structure of the minerals Perovskite and Ferropericlase although with differing chemical compositions and it is this seismic discontinuity at 650 km depth that marks the transition to the lower mantle.
Its heat comes from left over radiation from the Earth's creation.
It is more denser than the crust. not
It contains more iron than silica.
It is 1800 miles thick and makes up more than two thirds of earts mass
The ultimate source of heat that drives plate tectonics is believed to be the Earth's internal heat from radioactive decay in the mantle. This heat causes convection currents in the mantle, which in turn drive the movement of the tectonic plates.
An undersea mountain chain where new ocean floor is produced
magma moves up earth suface
Decompression melting occurs when a decrease in pressure on a mantle rock causes it to melt without an increase in temperature. This process is related to Earth's internal convection because rising mantle material undergoes decompression as it moves towards the surface, leading to melting and the formation of magma chambers.
The layer of the Earth that has melted rock that moves like a thick liquid is the asthenosphere, which is part of the upper mantle. The high temperature and pressure in this region cause rocks to partially melt, allowing them to flow slowly over long periods of time. This movement is what drives tectonic plate motion and causes features like earthquakes and volcanic activity.
in the mantle above the slab
Mantle plumes are in the mantle, BELOW the Earth's crust. The circulation of heat from the lower mantle to the upper mantle can cause "hot spots" in the overlying crust, heating the magma in the areas.
The older oceanic crust moves away from the spreading center and is eventualy subducted back into the mantle.
The crust moves on a plastic like layer of the mantle.
The crust moves on a plastic like layer of the mantle.
It moves because of convection currents
The ultimate source of heat that drives plate tectonics is believed to be the Earth's internal heat from radioactive decay in the mantle. This heat causes convection currents in the mantle, which in turn drive the movement of the tectonic plates.
Heat transfer in the Earth's mantle drives the movement of the Earth's crust through the process of convection. As mantle material heats up, it becomes less dense and rises, causing the overlying crust to move. At the same time, cooler mantle material sinks back down, completing the cycle of heat transfer and driving the continuous motion of tectonic plates.
the upper mantle
erosion
no that a earthquake
An undersea mountain chain where new ocean floor is produced