Ice volcanoes on Pluto
NASA’s New Horizons spacecraft flew past the dwarf planet Pluto at the outer edge of our solar system in 2015. The spacecraft sent back spectacular images that revealed a complex and varied world with active geological processes. One of the enigmatic features New Horizons discovered was a huge circular mounded edifice of ice, named Wright Mons. Wright Mons has very few impact craters on its surface, suggesting that its surface was created quite recently, possibly due to cryovolcanism (ice volcano eruptions).
To investigate this question, we used the data provided by New Horizons to study the area surrounding Wright Mons in detail. We also performed geophysical calculations to test whether the expansion of water-ammonia mixtures as they freeze in subsurface chambers could cause a cryovolcanic eruption big enough to produce Wright Mons.
Our surface mapping identified numerous features that are consistent with cryovolcanism including channels, lobate flows, and circular pits. Our calculations also suggest that freezing liquids in Pluto’s subsurface produces overpressure capable of fracturing the surrounding ice crust. Pressurized cryovolcanic fluids may then ascend along these fractures to the surface and erupt to produce cryovolcanic mounds like Wright Mons.
Topography data from NASA’s New Horizons mission showing the area around Wright Mons. Channel features around the summit of Wright Mons are indicative of cryovolcanic flows.
The freezing of water-ammonia mixtures in Pluto’s subsurface ocean and in trapped crustal chambers can produce enough overpressure to fracture the surrounding ice.
