Abandoned and corroded copper cable releases hydrogen gas; catastrophically combines with oxygen creating a blast.
Article: Exploring deep microbial life in coal-bearing sediment down to ~2.5 km below the ocean floor
Lignite coal bed, about 2 miles below the surface of the Pacific Ocean off of Japan. Buried for "tens of million of years." Still has an active bacterial ecosystem.
Article: New Horizons: Pluto may have 'nitrogen glaciers'
Scientists believe they see evidence of surface material having flowed around mountains and even ponding in craters.
The activity is certainly recent, they say, and may even be current.I love bizarre geology (or "plutology").
The other key detection was of hazes in the atmosphere. These are likely the consequence of high-up methane being broken apart and processed by sunlight into simple hydrocarbons like ethylene and acetylene, which then fall, cool and condense to form a mist of ice particles.And bizzare meteorology.