Scientists have long believed that planet Earth is the only planet in our solar system where plate tectonics existed, but new research out of the University of California Los Angeles has reversed this position, showing that Mars in fact also hosts this geological phenomenon.
“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,” said An Yin, a UCLA professor of Earth and space sciences and the sole author of the new research.
Yin, who has also conducted geological research in the Himalayas and Tibet, made the discovery while analysing approximately 100 satellite images from a NASA spacecraft known as THEMIS (Time History of Events and Macroscale Interactions during Substorms) and from the HIRISE (High Resolution Imaging Science Experiment) camera on NASA’s Mars Reconnaissance Orbiter.
“When I studied the satellite images from Mars, many of the features looked very much like fault systems I have seen in the Himalayas and Tibet, and in California as well, including the geomorphology,” said Yin.
Yin noticed, as one example, a very smooth, flat side of a canyon wall, which can only be generated by a fault. Yin also made note of the fact that Mars has a linear volcanic zone, a feature typical of plate tectonics.
“You don’t see these features anywhere else on other planets in our solar system, other than Earth and Mars,” said Yin, whose research is featured as the cover story in the August issue of the journal Lithosphere.
One primary focus for scientists over the decades has been the Valles Marineris (Latin for Mariner Valleys and named for the Mariner 9 Mars orbiter of 1971–72, which discovered it), the longest and deepest system of canyons in our solar system, measuring in at nearly 2,500 miles long, which works out to be around nin times longer than the Grand Canyon.
For decades, scientists have been wondering how the Valles Marineris formed.
“In the beginning, I did not expect plate tectonics, but the more I studied it, the more I realized Mars is so different from what other scientists anticipated,” Yin said. “I saw that the idea that it is just a big crack that opened up is incorrect. It is really a plate boundary, with horizontal motion. That is kind of shocking, but the evidence is quite clear.
“The shell is broken and is moving horizontally over a long distance. It is very similar to the Earth’s Dead Sea fault system, which has also opened up and is moving horizontally.”
Yin named the two tectonic plates divided by the Valles Marineris, Valles Marineris North and the Valles Marineris South, and found that they had moved approximately 93 miles horizontally relative to one another.