What layer lies beneath the crust where convection currents occur?

• A. Mantle
• B. Outer Core
• C. Inner Core
• D. Asthenosphere

Answer: (A)

Mantle convection is the slow, steady circulation of rock in a shell just beneath the crust. Heat from the deep interior causes mantle material to heat up, become less dense, rise, spread out, cool, and sink again, creating convection cells. This flowing mantle moves and drags the overlying tectonic plates, driving their movement.

The layer directly beneath the crust where this circulating flow occurs is the mantle. Within the mantle, the upper part—the asthenosphere—is particularly ductile and capable of flowing, which makes it the region most closely linked to plate motion. The outer core is a separate, deeper layer of molten metal whose convection generates Earth’s magnetic field, not the plate motions you see at the surface. The inner core is solid and doesn’t participate in convection in the same way.

So the layer beneath the crust where convection currents occur is the mantle.