A 70 degree shift on Jupiter’s icy Europe was the last event to break its surface

The outer icy shell of Europe has fully oriented itself in one of the latest geological events recorded on its young surface. The poles of Europe are not where they used to be. Cracks in the surface of Jupiter’s icy moon indicate that its ice scale has rotated 70 degrees over the last several million years. In addition to supporting preliminary evidence for the existence of an underground ocean, it also means that the geological history of the surface of Europe needs to be re-examined.

New research, led by the Senior Staff Scientist of the Universities Space Research Association, Dr. Paul Schenk at the Lunar and Planetary Institute (LPI), confirms that Europe’s large – scale, circular pattern is formed during a major reorientation of the icy exterior with respect to its spin axis, a process known as true pole rotation. This can only happen if the icy shell is detached, or floating freely, separated from the rocky core of the planet by a liquid water ocean. The findings were published July 29, 2020 in Geophysical research letters.

“Our main finding is that the fractures associated with real polar migration across Europe cut across all areas. This means that the real polar-striking event is very young and that the ice shell and all the features on it formed are more than 70 ° of are displaced latitude from where they were first formed, “reports Dr. Schenk. “If true, then the very recorded history of tectonics across Europe would need to be re-evaluated.”

With a combination of global maps from Galileo and Voyager data with improved precision, and detailed topographic data derived from them, a team of scientists from the LPI in Houston, the University of California at Santa Cruz, and the University of Arizona at Tucson correlated large fractures on the surface of Europe with previously identified concentric circular depressions on the surface.

NASA’s Galileo spacecraft orbited Jupiter from 1995 to 2003 and returned hundreds of images of the surface of Europe. Reconstruction of the global map of Europe at 200 meters resolution in color in preparation for a return to Europe revealed that these mysterious fracture systems were part of the circular true polar wandering patterns previously identified. Topographic mapping in images with the highest resolution of the fractures at 40 meters per pixel shows that the fractures are more than 200 meters deep. The fractures cut through all known sites and thus show that the deformation related to the global reorientation (as true polar wandering) was one of the last events that took place in Europe. These features also imply that the floating ice shell on Europe may have thickened over time.

“Another important aspect of this work is that it makes predictions for additional features and ice-shell properties that could be tested when the planned Europa Clipper spaceship begins to observe Europe,” says coin investor Francis Nimmo at the University of California at Santa Cruz.

“In addition to generating global-scale tectonic features, true polarization also produces global gravity and storms of shape, affecting gravity and shape constraints on interior structure,” says coin teller Isamu Matsuyama at the University of Arizona.

These can also be searched and tested when Europa Clipper arrives later this decade. Europa Clipper will complete the map of Europe, including high resolution images and sounds of these features. These maps will help determine the absolute age of these fractures and depressions and other consequences of the polar walking event that created them.

Provided by USRA