Pluto is home to a pair of spiky mountains with holes on the top. That sounds an awful lot like we just found a pair of cryovolcanoes on the distant frozen world!

The informally-named Wright Mons and Piccard Mons look like cryovolcanoes we’ve found on icy moons around the gas giants, volcanoes driven by the eruption of exotic water, nitrogen, ammonia and methane ice slurries instead of lava. They’re conical mountains with central summit depressions, and distinctive bumpy flanks.


Wright Mons digital elevation model where blue indicates slower terrain and brown indicates higher. Image credit: NASA/JPHAPL/SwRI

Located south of Sputnik Planum, Wright Mons is about 160 kilometers (100 miles) wide and 4 kilomters (13,000 feet) tall, with a 56-kilometer (34-mile) diameter summit depression ringed by concentric fractures. The flanks of the suspected cryovolcano are hummocky, a lumpy texture that may be the remains of old, cooled flows. Just south of Wright Mons, Piccard Mons is both bigger diameter and taller.


Wright Mons and Piccard Mons are joining other suspected cryovolcanoes on Europa and Doom Mons on Titan, and the confirmed erupting cryovolcanoes of Enceladus and Triton. More cryovolcanoes may exist on the icy moons of Ganymede and Miranda, and cyrovolcanics were briefly considered as an explanation for the strange bright white splotches on Ceres.

Piccard Mons digital elevation model where blue indicates slower terrain and brown indicates higher. Image credit: NASA/JPHAPL/SwRI


New Horizons postdoctoral researcher Oliver White offers a tentative interpretation:

“These are big mountains with a large hole in their summit, and on Earth that generally means one thing—a volcano.

If they are volcanic, then the summit depression would likely have formed via collapse as material is erupted from underneath. The strange hummocky texture of the mountain flanks may represent volcanic flows of some sort that have travelled down from the summit region and onto the plains beyond, but why they are hummocky, and what they are made of, we don’t yet know.”


Sharing their results at theAmerican Astronomical Society’s Division for Planetary Sciences meeting in National Harbor, Maryland earlier today, the mission scientists are all holding onto words of caution and tentative interpretations. When Jeff Moore stepped up to present, he offered the words of caution:

“We’re not yet ready to announce we have found volcanic constructs at Pluto, but these sure look suspicious and we’re looking at them very closely.”


No one wants to come out and be definite with labelling new landforms on Pluto based on one quick flyby, but if a pair of conical mountains with central summit depressions aren’t actually cryovolcanoes with eruption craters from spewing an icy slurry onto the dwarf planet, the explanation is going to get a whole lot weirder.

And if Pluto does have active cryovolcanoes? It could go a long way to helping us understand the mystery of Pluto’s weirdly active surface, and lends credence to the theory that Pluto’s geological activity might be fuelled by a subsurface ocean.


Top image: Wright Mons. Credit: NASA/JHUAPL/SwRI

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