Explain how convection currents drive the movement of tectonic plates in the lithosphere by describing the two plate interaction
s at letters D and E. Support your response by describing how convection current being shown at letters A, B and C are driving the interactions at letters D and E.
The semi-plastic rock of the mantle behaves like water being heated. The lower mantle is hotter than upper mantle because it is closer to the hotter core of the earth. Therefore, this part of the mantle is less dense and tends to rise as the upper cooler denser mantle close to the crust sink to the bottom. These convection currents are similar to those of water in a container being heated from below.
The circular motion of these currents tends to drag along the crust due to force of friction between the lower crust and upper mantle. This is what powers tectonic plate movements. When two plates are driven by currents that intersect and churn in the same direction, they collide, at a convergent boundary as shown in position D in the illustration. The denser plate is subducted beneath the other. At position E, two plates are moving away from each other (called a divergent boundary) because each plate is being driven by a different convention current in the mantle. These current are cycling in opposing directions (one clockwise the other anti-clockwise).
