7.347 (as of 2015). Nobody has gotten the chance to count.
Answer:
The answer is below
Explanation:
Most metamorphic rocks are formed from regional metamorphism. When two plates collide, it causes the release of large amount of pressure, this causes a deformation (folding and faulting) of the rock. As a result of the collision, the denser plate may be forced under the less dense plate thereby causing the rock to fall deep where they are subjected to high pressure and temperature.
Regional metamorphism produces green schist facies, amphibolite facies and granulite facies.
Convection currents occur in the MANTLE. The mantle is the second layer of the earth after the crust. The mantle is approximately 2900 km thick. Convection currents are triggered or fueled by the heat from the Earth's core.
The part of the mantle closest to the core gets heated. It then becomes less dense than the layers above so it rises. When this rising plume interacts with the crust it cools and becomes more dense than the layers below and so it sinks and this circular motion continues to form convection currents.
