After nearly forty years of research, scientists have finally proven that plate tectonics exist on Mars. A recently published paper by An Yin in the journal Lithosophere reveals that the origin of Valles Marineris on Mars — the longest trough system in the solar system — was formed by rifting, strike-slip faulting, and subsurface mass removal. Yin's research now shows that Earth's surface is not the only one in the solar system subject to the forces of plate tectonics.
The above image of Valles Marineris was composed by Robert L. Hurt.
Yin, who works out of UCLA, made the discovery by analyzing a hundred satellite images taken from NASA's THEMIS spacecraft. He was able to confirm his discovery by comparing the images to geological examples he had previously uncovered in the Himalayas, Tibet, and California — unique locations in which the Earth's major plates divide.
A good example is California's Death Valley, an area featuring a series of cliffs that were formed by a fault. Yin was able to compare these structures to a very smooth, flat side of a canyon wall on Mars which he believes could only be generated by a fault. Speaking through a release, Yin noted that, "You don't see these features anywhere else on other planets in our solar system, other than Earth and Mars."
Yin's analysis also solves the mystery about how Valles Marineris was formed. It's the longest and deepest system of canyons in our solar system — nearly 2,500 miles long and about nine times longer than the Earth's Grand Canyon. The trough is like a gaping wound on the Red Planet, and given that scientists had previously doubted the presence of tectonic activity on Mars, they were completely stumped about how it got there.
Some had merely suggested that it was a "big crack" that had just opened up. But Yin's work shows that Valles Marineris is in fact part of a plate boundary, one that's subject to slow, but persistent horizontal motion; the two plates have moved about 93 miles relative to each other. He compares it to Earth's Dead Sea fault system, a trough-like structure that is also moving horizontally. The finding indicates that Mars may be subject to earthquakes, or what should be more appropriately referred to as marsquakes.
The analysis also suggests that Mars's tectonic activities are excruciatingly slow, with major tectonic shifts occurring about every million years or so. Yin suspects that Mars is subject to a different kind of plate tectonics — one that may be the result of the planet just having two plates, as contrasted with Earth's seven. Yin's study can be found at the journal Lithosophere.
Inset image courtesy NASA/JPL-Caltech/USGS.