GEOLOGY

Detailed explanation-1: -The main heat transfer mechanism in the Earth’s mantle is convection, a thermally driven process where heating at depth causes material to expand and become less dense, causing it to rise while being replaced by complimentary cool material that sinks.

Detailed explanation-2: -How does convection work? Convection works by areas of a liquid or gas heating or cooling greater than their surroundings, causing differences in temperature. These temperature differences then cause the areas to move as the hotter, less dense areas rise, and the cooler, more dense areas sink.

Detailed explanation-3: -Because magma is less dense than the surrounding solid rocks, it rises toward the surface. It may settle within the crust or erupt at the surface from a volcano as a lava flow.

Detailed explanation-4: -As the heated mantle transfers its heat energy to the lithosphere, it becomes more dense than the surrounding magma and sinks back down towards the core.

Detailed explanation-5: -The movement of heat by convection in the asthenosphere causes the rock of the mantle to slowly move in huge streams. The solid (but brittle) rock of the lithosphere is resting directly on top of the solid (but soft) rock of the asthenosphere.