Large Igneous Province Formation
Earth has an outer shell made of a number of discrete, moving tectonic plates floating on a molten, convective mantle above a solid core. The mantle’s flow is driven by the descent of cold tectonic plates during subduction and the complementary ascent of plumes of hot material from lower levels. The surface of the earth reflects stretching, thickening and bending of the tectonic plates as they interact.
Ocean-plate creation at upwellings, spreading and subduction are well accepted fundamentals of plate tectonics, with the upwelling of hot mantle materials and the sinking of the cooler ocean plates driving the mantle convection. In this model, tectonic plates diverge at mid-ocean ridges, where hot mantle rock flows upward to fill the space. Plate-tectonic processes account for the vast majority of Earth’s volcanism.
Beyond the effects of convectively driven motion, deep processes have other influences on the surface topography. The convective circulation drives up-wellings and down-wellings in Earth's mantle that are reflected in local surface levels. Hot mantle materials rising up in a plume can spread out radially beneath the tectonic plate causing regions of uplift. These ascending plumes play an important role in LIP formation.
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