Which force operates at destructive plate boundaries to pull the denser slab into the mantle?

Which force operates at destructive plate boundaries to pull the denser slab into the mantle?

• A. Ridge push
• B. Slab pull
• C. Mantle convection
• D. Gravitational sliding

Answer: (B)

Slab pull is the gravity-driven downward force from a dense, sinking oceanic plate as it subducts into the mantle at a subduction zone. The heavy slab weighs the plate, and as it sinks, it pulls the rest of the plate along with it, making this the main force at destructive plate boundaries. Ridge push happens at mid-ocean ridges where rising magma creates a slight outward push of the lithosphere; mantle convection is the broader mantle movement that powers plate tectonics, not the boundary-specific pull; gravitational sliding isn’t the standard description used for this process.

Slab pull is the gravity-driven downward force from a dense, sinking oceanic plate as it subducts into the mantle at a subduction zone. The heavy slab weighs the plate, and as it sinks, it pulls the rest of the plate along with it, making this the main force at destructive plate boundaries. Ridge push happens at mid-ocean ridges where rising magma creates a slight outward push of the lithosphere; mantle convection is the broader mantle movement that powers plate tectonics, not the boundary-specific pull; gravitational sliding isn’t the standard description used for this process.