12,000 square miles of thick icy material forced under another ice shell
Space news – (Europa) – Planetary space geologists have looked for years for telltale signs of plate tectonics occurring elsewhere in the solar system, other than Earth. Indications of this geological process taking place on other planetary bodies could mean the processes geologists observe here are possibly common in the solar system.
Recently, space scientists looking at images taken of Europa by NASA’s Galileo spacecraft during a flyby in the early 2000s, discovered unusual geological features they believe indicates the process of plate tectonics is taking place on the surface. You can learn more about Europa and view the images here
Image Credit: Noah Kroese, I.NK
Planetary space geologist Simon Kattenhorn, working at the University of Idaho, and Louise Prockter, of Johns Hopkins University Applied Physics Laboratory, discovered geological boundaries indicating the surface of Europa had recently shifted significantly in the northern latitudes.
Planetary space geologists see areas in the northern latitudes of Europa where the new ice crust has thrust up from below and then spread into bands miles wide. This planetary space geologists believe occurs in a process possibly similar to seafloor spreading on Earth, which is part of the theory of plate tectonics. Plate tectonics, or continental drift, is the theory the Earth’s crust and upper mantle, or lithosphere, is composed of slowly drifting tectonic plates of various sizes.
On our home planet, while new sea floor is forming at mid-ocean ridges, old surface is annihilated at subduction zones. Subduction zones are surface areas where two tectonic plates meet and then overlap as one is pushed beneath the other. Despite the mile wide bands of the new surface on Europa, however, planetary space geologists couldn’t understand how the top layer was able to accommodate the volume of new crust being formed.
“We have been puzzled for years as to how all this new terrain could be formed, but we couldn’t figure out how it was accommodated,” said Prockter. “We finally think we’ve found the answer.”
Planetary space geologists rearranged the Galileo images they were looking at into their original positions to get a view of these new surface regions before they moved. They found 12,000 square miles (almost 20,000 square kilometers) of the old surface area in the northern latitudes was gone.
Planetary geologists also saw ice volcanoes erupting on the surface in the regions in question in the images, which they think could be formed due to the melting and absorption of one icy plate as it’s pushed beneath another at a subduction zone.
“Europa may be more Earth-like than we imagined if it has a global plate tectonic system,” Kattenhorn says. “Not only does this discovery make it one of the most geologically interesting bodies in the solar system, it also implies two-way communication between the exterior and interior — a way to move material from the surface into the ocean — a process which has significant implications for Europa’s potential as a habitable world.”
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