Planetary volcanism - Essay Example

Planetary Volcanism Planetary Volcanism Volcanism refers to the process through which magma (molten rocks) erupts onto a planet’s surface. On the other hand, a volcano refers to a vent or opening through which magma is ejected onto a planet’s surface. Volcanism generally occurs when a planet’s internal heat is lost. Volcanoes usually form when the internal heat of a planet is sufficient to cause rocks near the surface to melt. Volcanic activity is directly responsible for forming at least three quarters of the surface rocks of the Earth and Venus (McFadden, Weissman & Johnson, 2007).

Volcanism on Earth occurs as a result of plate movements. Because of very high temperature in the inner core of the earth, the interior material is usually in molten state (Greeley, 2013). When two plates move further apart, the earth’s interior materials progressively rise up and occupy the vents created by plate movement. Magma chambers may also form in cases where plate move over each other. Despite the fact that volcanism on earth usually takes place at boundaries between plates, it can also happen at the hotspots within the plates’ interiors.

Very high temperature of the earth’s interior causes materials within the inner part to melt. This molten material is then ejected to the earth’s surface under high pressure. When magma reaches the surface of the earth, it solidifies into thick lava, which eventually forms volcanic rocks. Volcanoes on earth are mainly categorized into two: shield and composite volcanoes (Greeley, 2013).Evidences of volcanism have also been noticed in the Earth’s moon. The moon is characterized by small volcanoes, crevices as well as widespread basalt lava flows (Greeley, 2013).

The moon’s large and dark basins, often called the mare, are flows of lava. However, there exist no sign of active volcano on the moon’s surface and all the evidences of volcanoes are archaic. Volcano in the planet moon, occurred millions of years ago and no recent volcanic activity has been observed in the recent past.Mars also has exhibits of volcanism. The planet has volcanic features that are akin to those on Earth, but a bit larger. Mars has shield volcanoes with Olympus Mons (22 kilometers) being the solar system’s tallest volcano.

The Tharsis region hosts most volcanoes in Mars (Kusky, 2005). Similar to volcanoes on Earth, the volcanoes in Mars are believed to have formed from materials ejected from the deep and hot interior of the planet. Unlike the Moon, many scientists believe Mars has active volcanoes. Basalt meteorites are perfect indicators that volcanism occurred in Mars many years ago (Foulger, & Jurdy, 2007). Despite volcanoes on Mars being considered as active, there is no evidence of recent volcanic eruptions and lava flows that can be observed happened millions of years ago.

Venus is characterized by numerous volcanic features, which appear to have been formed just a few years ago because they are not weathered. Basalt lava flow covers most parts of the surface planet. Most volcanoes are mainly shield volcanoes because Venus lacks tectonic plates. Volcanoes on Venus spread hundreds of kilometers and are flatter compared with those on earth. Volcanism on Venus is also associated with novae. Novae form when vast amounts of magma accumulate on the surface, forming radiating ridges as well as high radar reflective troughs.

Jupiter’s innermost moon also known as Io is characterized as the solar system’s most active volcanic body (McFadden, Weissman & Johnson, 2007). Planetary volcanism occurs because of temperature variations between the surface and inner core of the planets.ReferencesFoulger, G. R., & Jurdy, D. M. (2007). Plates, plumes, and planetary processes. Boulder, Colo: Geological Society of America.Greeley, R. (2013). Introduction to planetary geomorphology. New York: Cambridge University Press.Kusky, T. M. (2005).

Encyclopedia of earth science. New York, NY: Facts on File.McFadden, L.-A. A., Weissman, P. R., & Johnson, T. V. (2007). Encyclopedia of the solar system. Amsterdam: Academic.