Idunn Mons is a

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's 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 v ...

on the planet

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...

. It is named after

Iðunn In Norse mythology, Iðunn is a goddess associated with apples and youth. Iðunn is attested in the ''Poetic Edda'', compiled in the 13th century from earlier traditional sources, and the ''Prose Edda'', written in the 13th century by Snorri St ...

, a goddess in

Norse mythology Norse, Nordic, or Scandinavian mythology is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia, and into the Nordic folklore of the modern period ...

Structure

The volcano rises above the flat highlands of Imdr Regio, an igneous province, to a height of , and is approximately 250 km in diameter. It rises approximately 3.6 km above the mean planetary radius. Lava flows originating from the volcano have traveled in all directions, reaching as far as 550 km. The Olapa Chasma, a 1,300-km-long

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...

system, crosses the volcano in a northwest–southeast direction. The volcano features a 45-km-wide, flat-topped summit at its center. A cluster of overlapping

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

s between 14 and 17 km in diameter is centered at the summit. To the northeast of the caldera cluster is a done-shaped feature. The flat-topped summit may be explained by flank collapses due to tectonic instability as it is situated within the Olapa Chasma rift. These flank collapses altered the topography of the volcano. Young summit lava flows began to cover the affected ares, eventually burying the collapse area in new flows that reconstructed the flank.

Activity

There are claims by scientists that Idunn Mons is volcanically active or was active recently, although no eruptions have been directly observed. Volcanism on Venus is not well-studied, but the lack of

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

s and discovery of

phosphine Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...

in the chemical composition of its atmosphere suggest recent or ongoing volcanic activity. Recent lava flows have buried evidence of rift fractures and lateral collapse, and the lack of erosion suggest young eruptive activity. Along the eastern flank are possible collapse scars and amphitheater-like structures that may represent

parasitic cone A parasitic cone (also adventive cone or satellite cone) is the cone-shaped accumulation of volcanic material not part of the central vent of a volcano. It forms from eruptions from fractures on the flank of the volcano. These fractures occur ...

s. Previous studies have dated the lava flows at 2.5 million to 250,000 years old. However, a 2021 study published by the

American Astronomical Society The American Astronomical Society (AAS, sometimes spoken as "double-A-S") is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC. The primary objective of the AAS is to promote the adv ...

suggests the last eruption of Idunn Mons may have occurred from within the last 10,000 years to as recent as several years ago.

References

External links

PIA13001: Surface Warmth on a Venus Volcano
{{Venus Volcanoes of Venus Mountains on Venus Polygenetic shield volcanoes

Structure

Activity

See also

References

External links