What is the main factor driving the movement of tectonic plates?

The movement of tectonic plates is primarily driven by convection currents in the mantle. These currents are created by the heat generated from the Earth’s core and the decay of radioactive elements within the mantle. As hot material rises towards the Earth’s crust, it cools down and sinks back down, creating a continuous cycle of movement. This process effectively transfers energy through the mantle and creates the necessary forces that propel the tectonic plates across the Earth's surface.

The convection currents result in the plates either colliding, separating, or sliding past each other, which can lead to geological phenomena such as earthquakes, volcanic activity, and the formation of mountains. This underlying mechanism is fundamental to the theory of plate tectonics, as it explains how the massive sections of the Earth’s lithosphere are in constant motion.