OCEAN ISLAND BASALT Meaning and
Definition
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Ocean Island Basalt refers to a type of volcanic rock that is formed through the eruption of volcanoes located in the middle of ocean basins. It primarily consists of basalt, which is an igneous rock composed primarily of calcium-rich plagioclase feldspar, pyroxenes, and olivine.
These volcanic eruptions occur when hot magma rises to the surface from deep within the Earth's mantle, due to the movement of tectonic plates. The magma, rich in iron, magnesium, and calcium, then solidifies and cools rapidly as it is exposed to the colder ocean water. This rapid cooling process gives rise to the characteristic fine-grained texture of ocean island basalts.
Ocean island basalts are distinct from other volcanic rocks, such as mid-ocean ridge basalts, as they are formed in isolated volcanic systems far away from the boundaries of tectonic plates. These volcanic systems are often found in regions of upwelling hot mantle material called hotspots, which are believed to be caused by fixed mantle plumes that originate deep within the Earth.
Ocean island basalts can be found in several well-known volcanic island chains, such as the Hawaiian Islands, the Canary Islands, and the Galapagos Islands. They have significant scientific importance as they provide valuable insights into the composition and behavior of Earth's mantle, as well as the geological processes occurring within the deep oceans.
