A pancake dome is an unusual type of
lava dome found on the planet
Venus
Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...
. They are widely scattered on that planet and often form groups or clusters, though with smaller numbers of pancake domes in each group than is typical for the more common
shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava ...
s. They are commonly found near
coronae and ''tesserae'' (large regions of highly deformed terrain, folded and fractured in two or three dimensions, believed to be unique to Venus) in the lowland plains. Pancake domes are between 10 and 100 times larger than
volcanic domes formed on Earth.
Description
Pancake domes have a broad, flat profile similar to shield volcanoes and are thought to form from one large, slow eruption of viscous
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...
-rich
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 ...
.
They usually have a central pit- or bowl-like feature similar to a
volcanic crater
A volcanic crater is an approximately circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During volcanic eruptions, molten magma and volcanic gases rise from an ...
, but it is thought that these pits form after the eruption as the lava cools and emits gas rather than being a
vent from which the lava originated. The surface of pancake domes are covered with patterns of small cracks and faults.
See also
*
Arachnoid
*
Volcanism on Venus
References
*
*
*"Shapes of Venusian 'Pancake' Domes Imply Episodic Emplacement and Silicic Composition." https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1064&context=geology_fac
Volcanoes of Venus
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