This is an image of "puddle-like" flows of Europa taken by the Galileo spacecraft. This image is called "the mitten".
Click on image for full size
The picture seems to show the presence of a "puddle" which has seemingly wiped out the linea or raised ridges nearby. Scientists cannot prove that this feature is really the remnants of a puddle, but such a patch probably involves a local pocket of water which refroze on the surface.
This feature suggests a third process, one which geologists call "cryovolcanism" or icy-volcanism (cryo means cold). In this case, even though a volcanic cone is not formed, a liquid comes out of the ground and flows on the surface. That is why this feature gets the name cryovolcanism.
You may leave the tour and read more about terrestrial volcanism and how volcanic cones are formed on Earth using the link at the bottom of the page.
This is page 9 of 20
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, ranging from seismology
, rocks and minerals
, and Earth system science