What is most responsible for any movement in the Earth’s rock plates?
The movement of the Earth's rock plates is primarily caused by plate tectonics. Plate tectonics refers to the movement of the rigid lithospheric plates that cover the Earth's surface. These plates float on the semi-fluid asthenosphere beneath them. The main driving force behind plate tectonics is the convective currents in the underlying mantle of the Earth.
The convective currents in the mantle are generated by the heat produced from the decay of radioactive elements and from heat leftover from the formation of the Earth. These convection currents cause the asthenosphere to slowly move, which in turn drags and moves the overlying lithospheric plates.
There are three main types of plate boundaries where movement occurs:
1. Divergent plate boundaries: Here, two plates move away from each other. As the convection currents cause the asthenosphere to move, it creates tensional forces that pull the plates apart, resulting in the formation of new crust.
2. Convergent plate boundaries: Here, two plates collide with each other. The density differences of the plates cause one plate to subduct or dive beneath the other. This subduction leads to the formation of mountain ranges, volcanic activity, and deep ocean trenches.
3. Transform plate boundaries: Here, two plates slide past each other horizontally. As the convection currents drag the plates, they can get locked or stuck. When the stress along the locked boundary exceeds the strength of the rocks, it is released in the form of an earthquake.
In summary, the movement of the Earth's rock plates is primarily driven by the convective currents in the underlying mantle, which in turn causes the lithospheric plates to move at plate boundaries.