2014-09-08. Scientists Find Evidence of ‘Diving’ Tectonic Plates on Jupiter’s Moon Europa.

posted Sep 9, 2014, 2:14 AM by Alan Gould

For GSS A Changing Cosmos chapter 7. Excerpt: Scientists have found evidence of plate tectonics on Jupiter’s moon Europa. This indicates the first sign of this type of surface-shifting geological activity on a world other than Earth. ...While examining Europa images taken by NASA’s Galileo orbiter in the early 2000s, planetary geologists Simon Kattenhorn, of the University of Idaho, Moscow, and Louise Prockter, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, discovered some unusual geological boundaries. ...When Kattenhorn and Prockter rearranged the icy terrain in the images, they discovered about 7,700 square miles (about 20,000 square kilometers) of the surface were missing in the moon’s high northern latitudes. Further evidence suggested the missing terrain moved under a second surface plate -- a scenario commonly seen on Earth at plate-tectonic boundaries. Kattenhorn and Prockter saw ice volcanoes on the overriding plate, possibly formed through melting and absorption of the slab as it dove below the surface, and a lack of mountains at the subduction zone, implying material was pushed into the interior rather than crumpled up as the two plates mashed against each other. The scientists believe the subducted area was absorbed into Europa's ice shell, which may be up to 20 miles (about 30 kilometers) thick, rather than breaking through it into Europa's underlying ocean.  ...Previous scientific findings point to the existence of a liquid water ocean located under the moon’s icy crust. This ocean covers Europa entirely and contains more liquid water than all of Earth's oceans combined. ...For more information about Europa and images of the plate tectonics, visit: http://solarsystem.nasa.gov/europa. Information is available online about the Galileo Mission at: http://www.jpl.nasa.gov/missions/galileo .... http://www.nasa.gov/press/2014/september/scientists-find-evidence-of-diving-tectonic-plates-on-jupiter-s-moon-europa/#.VA7BmUiyPZE. By NASA RELEASE 14-241.