GEOLOGY

Detailed explanation-1: -Lighter (less dense), warm material rises while heavier (more dense) cool material sinks. It is this movement that creates circulation patterns known as convection currents in the atmosphere, in water, and in the mantle of Earth.

Detailed explanation-2: -The mantle is heated from below (the core), and in areas that are hotter it rises upwards (it is buoyant), whereas in areas that are cooler it sink down.

Detailed explanation-3: -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-4: -Mantle convection occurs because relatively hot rocks are less dense and rise in a gravitational field while relatively cold rocks are more dense and sink. The rise of hot rocks advects heat upward while the fall of cold rocks advects cold downward; this counterflow is equivalent to an upward heat flux.

Detailed explanation-5: -Convection currents transfer hot, buoyant magma to the lithosphere at plate boundaries and hot spots. Convection currents also transfer denser, cooler material from the crust to Earth’s interior through the process of subduction.