Yellowstone, like the Hawaiian Islands, is believed to lie on top of one of the planet's few dozen hotspots where light hot molten mantle rock rises towards the surface. (sciencedaily.com)
They rise up to the lithosphere, bringing with them hot partially molten mantle material that causes the lithosphere to weaken and deform. (sciencedaily.com)
Geophysicists have sketched the broad outlines of plate tectonics — how Earth's molten mantle of lava rises up to the surface and turns into plates of rigid crust — but many mysteries remain. (discovermagazine.com)