What is a magma composition

What kind of volcano is not associated with a plate boundary?

The vast majority of volcanic activity occurs where tectonic plates collide or spread known as convergent boundaries. However, there is a special class of volcanoes that form in plates. These inter-plate volcanoes are known as hotspot volcanoes. Hotspot volcanoes that form under continental plates are called super volcanoes, which are the strongest and most violent volcanoes on earth.

Hotspot volcanoes

In contrast to volcanoes, which are connected with plate boundaries, hotspots or intermediate plates, volcanoes are located within tectonic plates. They are powered by localized sources of high thermal energy known as thermal springs. These plumes of molten rock, called magma, rise from the lower asthenosphere. They are much hotter than the typical lithospheric rock. This magma melts the surrounding area of ​​the crust, creating magma chambers and, when the magma reaches the surface, hotspot volcanoes. As the plate moves over the hotspot, a series of volcanoes forms. Tracking the sequence, from oldest to newest, identifies both the location of the hotspot and the relative movement of the tectonic plate over it.

Inter-Oceanic Hotspot Volcanoes

Interoceanic hotspots form under oceanic plates. The magma that is formed in these magma chambers is basaltic in nature and has a low viscosity and low water content. This type of magma mainly produces very fluid lava flows. The pressure is tending Not to form in inter-ocean magma chambers; rather, their corresponding volcanoes tend to continuously ooze running lava. This process creates shield volcanoes with wide, gently sloping sides. Mauna Loa and Kilauea on the Hawaiian island chain are examples of inter-ocean hotspot volcanoes.

Inter-continental hotspot volcanoes

Intercontinental hotspots form under continental plates. The melting of the continental crust creates a very different magma composition that is very rocky and dense. Pressure builds up in these magma chambers until the crust above the chamber breaks. This break-up immediately releases the pressure and allows the gas trapped in the magma to expand rapidly. This rapid expansion results in a large, violent, and explosive eruption. As the chamber empties rapidly, the surface above the chamber collapses, forming a large, bowl-like caldera. Intercontinental hotspot volcanoes are known as super volcanoes because they cause the largest volcanic eruptions. The Yellowstone supervolcano is an example of an intercontinental hotspotvolcano.

Results from Super Volcano Eruptions

When intercontinental supervolcanoes erupt, they create pyroclastic currents that can stretch for hundreds of kilometers and expel vast amounts of material that can cover the entire earth in a measurable amount of ash. This large output also creates a large amount of suspended matter in the atmosphere, leading to global cooling. The crater on Mount St. Helens is 2 square miles; However, the Yellowstone super volcano caldera is 1,500 square miles in size. The last Yellowstone eruption 640,000 years ago dropped 250 cubic miles of material, about 8,000 times the eruption of Mount St. Helens in 1980. The Yellowstone eruption 2.1 million years ago dropped 588 cubic miles of material, nearly 20,000 Times as much as the 1980 eruption of Mount St. Helens.
Main Geology What type of volcano is not associated with a plate boundary?

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