In the structural analysis of plate tectonics and mantle dynamics, which of the following mechanisms provides the primary driving force for lithospheric plate motion by pulling dense, cold slabs downward into the asthenosphere at convergent boundaries?

💡 Solution & Explanation

Slab pull is widely recognized as the dominant force driving tectonic plate motion, generated as cold, dense oceanic lithosphere sinks into the warmer asthenosphere at subduction zones. Ridge push plays a secondary role by driving plates away from buoyant mid-ocean ridges through gravitational sliding. Mantle convection supplies the overarching thermal framework, but direct gravity-driven forces at plate margins dictate plate velocities. Subducting slabs can penetrate deep into the lower mantle before melting completely.