  In data from the New Horizons encounter with Pluto in 2015, attention was
called to a crater named Kiladze and its surroundings because of the water ice
spectral properties, which contrast with the primarily methane ice regional
surface composition. The water ice carries the spectral signature of an
ammoniated compound, similar to that seen at two other sites on Pluto where
cryovolcanism has been identified. The faulted structure of Kiladze, including
shaping by numerous collapse pits and the distorted shape of the crater, are
compatible with the surroundings in Hayabusa Terra, east of Spunik Planitia.
They are further compatible with an interpretation as a resurgent caldera
formed during a past era of active cryovolcanic period that appears to be
significantly more recent than the overall age of the planet's surface,
possibly in the last several million years. In view of the size of the caldera
and the large scale of the surrounding distribution of water ice, we propose
that Kiladze is a "supervolcano" in which one or more explosive events has
scattered more than ~1000 km$^{3}$ of icy cryomagma erupted from the interior
onto the surface.
