The process of mantle convection is a continuous cycle that involves three main steps:
Upwelling: The first step in the process of mantle convection is the upward movement of hot, less dense material from the Earth's interior. This material rises because it is less dense than the surrounding material and is heated by the Earth's core.
Advection: As the hot material rises, it begins to move laterally, or "advect," as it is pushed and pulled by the surrounding material. This movement is caused by the flow of heat and material in the mantle, and it helps to distribute heat throughout the Earth's interior.
Downwelling: As the hot material reaches the surface, it cools and becomes denser. It then sinks back down into the mantle, completing the cycle of convection. This downward movement is known as "downwelling."
Overall, the process of mantle convection is a continuous cycle of upwelling, advection, and downwelling that plays a key role in shaping the Earth's surface and distributing heat throughout the Earth's interior.