Econintersect: Scientists have long thought that plate tectonics was a phenomenon occurring only on earth within our solar system. According to Wikipedia, rocky 
planets smaller than earth (like Mars) have not been considered candidates for the process and, of course, giant gaseous planets do not have the required crust. That became debatable in 2005 when the Huygens Probe which landed on Titan, the largest moon of Saturn, on January 14, 2005, returned images reported to show tectonic activity. However, a report from NASA in 2008 concluded that the tectonic activity on Titan was a process distinct and different than the plate tectonic activity on earth. Now An Yin, professor of Earth and Space Sciences at UCLA, reports that analysis of Mars satellite images reveals that Mars has a number of features that are consistent with plate tectonics, such as large vertical displacements (cliffs), very long canyons (possible rifts?) and other signs of massive horizontal movements. (Note: The suggestion of rifts is by Econintersect, not by Ptof. Yin.) The research was published in the journal Lithosphere.
The following is a map image of a tectonically active area on Mars that has at its center a canyon system far larger than the Grand Canyon on Earth.
Yin says the features he sees on Mars are consistent with a planet in early stages of plate tectonics. From R&D Magazine:
“Mars is at a primitive stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked and may help us understand how plate tectonics began on Earth,” says An Yin, a UCLA professor of Earth and space sciences and the sole author of the new research.
Mars appears to possibly have only two major plates, compared to the seven on Earth. This may be similar to early earth crustal plate structure or may simply be the result of Mars smaller size (about 1/2 the mass of Earth). If the latter then the Mars tectonic structure may never advance to the “broken egg shell” crustal structure of earth.
The following picture is a view of an interior part of the Valles Marineris (shown on the map above).The curved white strips inside the valley are sedimentary layers produced by nearby fault motion.
High resolution photo was taken by Context Camera on board the Mars Reconnaissance Orbiter (2006).
One of the features that was found in the study of apparent tectonics on Titan, the alignment of many craters that could be volcanic in origin along extended lines (like the Earth’s ring of fire). Mars has volcanos associated with an area that Yin has associated with a major fault complex. See the following video. Also on the video Prof. Yin and students demonstrate tectonic plate simulation models that they use in the laboratory to develop understanding the types of plate movements that can produce surface features similar to those observed on Earth, Venus and Mars.
Note: Do not be confused when Prof. Yin interchanges the names Earth and Mars.
Sources:
- Scientist discovers plate tectonics on Mars (Associated Press, R&D Magazine, 10 August 2012)
- UCLA Scientist discovers plate tectonics on Mars (Stuart Wolpert, UCLA News Release, 09 August 2012)
- Structural analysis of the Valles Marineris fault zone: Possible evidence for large-scale strike-slip faulting on Mars (An Yin, Lithosphere, 04 June 2012)
- Many secondary references and sources linked within the text of the article.
