NASA’s Dawn spacecraft has just sent back some new observations on the dwarf planet Ceres, and they’re fascinating: scientists have found an isolated mountain near the equator that they believe was formed as a weird salty-mud volcano that spewed out icy, salty water mixed with mud instead of molten rock like here on Earth.

They called it Ahuna Mons, and researchers see it as evidence of a bizarre type of volcanism unlike anything seen pretty much anywhere else. The volcano is no longer active, but it didn’t become dormant that long ago. In fact, scientists were qutie surprised to discover that volcanism on this isolated dwarf planet is so recent, as typically only planets have volcanism.

And it’s also surprising because Ceres is made of salts, muddy rocks and ice, which are not the usual ingredients for volcanism. It shows that perhaps there are a lot more volcanoes in our solar systme than we thought they were.

The research team used images and 3D terrain maps gathered by Dawn to map out Ahuna Mons and find out more about this mysterious feature.

“Dawn has revealed that Ceres is a diverse world that clearly had geological activity in its recent past,” said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles. “We’re very excited to follow up on this and the other discoveries about this fascinating world.”