The St. Helena hotspot is a

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

hotspot Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tr ...

located in the southern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

. It is responsible for the island of

St. Helena Saint Helena (, ) is one of the three constituent parts of Saint Helena, Ascension and Tristan da Cunha, a remote British overseas territory. Saint Helena is a volcanic and tropical island, located in the South Atlantic Ocean, some 1,874 km ...

and the St. Helena Seamount chain. It is one of the oldest known hotspots on Earth, which began to produce

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

about 145 million years ago.Mantle plumes and their record in earth history
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References

Geography of Saint Helena Hotspots of the Atlantic Ocean Geology of Saint Helena, Ascension and Tristan da Cunha Volcanoes of Saint Helena Mid-Atlantic Ridge {{Volcanology-stub