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Mantle plumes are large bulbs of magma from the Earth’s mantle that trigger major volcanism and can last for over a million years. They are a primary mechanism for cooling the Earth’s core and mantle. Evidence comes from geophysical models and persistent hot spots, such as the Hawaiian-Emperor seamount chain. Mantle plumes are thought to cause large igneous provinces, including supervolcano events like the one that occurred in Yellowstone Park 2.2 million years ago.
Mantle plumes are powerful geological events that consist of a large bulb of magma from the mantle, hundreds of miles wide, rising into the upper crust and triggering major volcanism. Visually, they would look similar to the rising shapes in a lava lamp. They can last for more than a million years, producing a phenomenon called a hotspot. Mantle plumes are thought to be a primary mechanism for cooling Earth’s core, which is a superheated ball of solid iron and nickel. Plumes are also a method of cooling the mantle, but it is thought to be a distant second to heat loss at tectonic plate boundaries.
Evidence for mantle plumes comes in the form of geophysical models of the Earth’s interior, as well as persistent hot spots that remain stationary relative to the rest of the mantle, but move relative to the crust as tectonic plates slowly drift over the course of million years. This drift effect is responsible for the Hawaiian-Emperor seamount chain, which has provided crucial evidence for mantle plumes showing cyclical periods of intensity in eruptions in the geological history of the hotspot. The mantle plume that produced Hawaii is one of the best known in the world, due to its central location in the Pacific Ocean and the prodigious amount of volcanic material it produced. When measured from the ocean floor, the Big Island of Hawaii is about 50% larger than Mt. Everest.
Mantle plumes are thought to be the cause of large igneous provinces. A large igneous province is a field of igneous rock, with an extension of a few million km2, with volumes of the order of 1 million km3, created in a geologically short period, less than a million years. These can be formed by the slow and continuous eruption of lava or by the rather sudden release of lava in a so-called supervolcano event. 2.2 million years ago, a supervolcano in what is now Yellowstone Park ejected 2,500 km3 of lava in a sudden eruption, blanketing North America in ash and blanketing the Earth in a volcanic winter that may have initiated a global cooling unchecked.
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