NASA’s New Horizons spacecraft has found signatures of ammonia on Pluto, which probably spurted from under the surface in fountains relatively recently
Source:
https://www.newscientist.com/article/2204739-pluto-is-coloured-red-by-ammonia-spewing-from-underneath-its-surface/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home