Which mechanism causes mantle plume volcanism far from subduction zones or plate boundaries?

💡 Explanation

When the mantle is locally heated, a mantle plume forms due to thermal expansion, causing buoyant upwelling because hot material is less dense, leading to volcanism far from plate boundaries. Therefore, buoyant upwelling results, rather than extrusion, sliding, or rollback which are related to plate boundary forces.

• Which mechanism causes increased flood frequency in populated regions near alluvial fans after prolonged drought?
• Which phenomenon causes localized regions of downwelling within subtropical gyres in the ocean?
• Which mechanism causes increased stream discharge variability in regions transitioning from glacial to fluvial drainage patterns?
• Which outcome occurs when sediment pore pressure reduces during subduction?
• Which mechanism causes the Intertropical Convergence Zone to experience a seasonal shift in latitude?
• Which oxygen level results when intensified upwelling occurs?