Tectonic Plates on Mars?

Tectonic plates on Earth are large pieces of the crust which make up the lithosphere. They float on top the asthenosphere (upper mantle) of the Earth and are responsible for making mountains, faults, trenches, earthquakes, volcanoes and probably some other things too.

So I asked, do other planets in our solar system have tectonic plates too?

After doing some research, I was both satisfied and disappointed with what I found.

I came upon 2 articles, both say that Mars has tectonic plates, but one says that Mars is in the early stages of plates while the other argues that Mars no longer appears geologically active.

I found this really interesting as it's always fun to have multiple opinions on things such as this. Proof of Mars' tectonic plates is mostly directed at the Valles Marinaris. This is a very, very, very long canyon system, that stretches a distance equivalent of New York to Los Angeles and is over 5 times the depth of the Grand Canyon. After many photos of the canyon, a scientist has discovered remarkable resemblance to the faults in the Himalayas. Tibet, and California which could suggest that it could have formed from plates.

Canyon on Mars captured by NASA's Mars Reconnaissance Orbiter

Mars is also home to the highest mountain in the solar system, Olympus Mons which is a pretty sick name. It's roughly 3 times the height of Mt. Everest and covers a surface area of about... the state of Arizona

Image Courtesy of NASA, image of Olympus Mons as compared to Arizona

It is believed that Mars has 2 plates, in which the canyon lies right in between them. When the canyon is is examined, scientists and astronomers have found matching sides that are seperated by 150 km which is why Mars is said to have 2 plates only.

Now, one article says that "Mars is at a primitive stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked."(An Yin). What is being said here is that Mars is only at the beginning of it's geological processing age as the plates are only developing, as the early Earth did as well. However, Sophie Allan from the National Space Center says that Mars no longer appears to be geologically active, meaning that the plates were possibly once in a more "healthy" state with more action and movement but has now slowed down, and stopped. I personally agree with the second article (halt to tectonic plate formation) as it wouldn't make too much sense that Mars is only now showing signs of plate movement. Mars is further away from the sun than the Earth so it makes sense that Mars' core and inner layers could have cooled faster than the Earth's which led to the gradual stop of the tectonic plates. Also, the size of Mars is quite smaller than Earth's as well.

Image Courtesy of NASA, the Valles Marineris as compared to the USA

So my question to you guys is, what do you think is the story behind Mars' tectonic plates?

You can read the full articles here:
http://news.discovery.com/space/shift-happens-mars-may-have-plate-tectonics-120820.htm
http://www.spaceanswers.com/solar-system/does-mars-have-tectonic-plates/