What happens to the crust at the top of one of the convection currents in the mantle?

At the top of a convection current in the mantle, the crust can either be pushed upward to form mountains or pulled apart to create rift valleys, depending on the nature of the current. As hot mantle material rises, it can cause the overlying crust to bulge, leading to tectonic activity. Additionally, when the convection current cools and sinks, it may create subduction zones where crust is pulled down into the mantle. This dynamic process contributes to the movement of tectonic plates and is essential in shaping the Earth's surface.