PHYSICS WORLD
Martian landscape
A geologist in the US claims to have found the first strong evidence for plate tectonics on Mars by studying satellite images of a huge trough in the Martian surface. It had been thought, until now, that tectonic movements were only present on Earth.
An Yin, professor of geology at the University of California, Los Angeles, spotted the tectonic activity in Valles Marineris – a 4000-km-long canyon system named after the Mariner 9 Mars orbiter that discovered the system in the 1970s. Valles Marineris stretches one-fifth of the way round the Martian surface and reaches depths of up to 7 km. The Earth’s 1.6-km-deep Grand Canyon is a mere surface scratch in comparison.
The formation of Valles Marineris is still not understood despite four decades of research. The most widely accepted theory is that spreading apart of the Martian surface created the system, similar to how rift valleys form on Earth, with the resulting crack being deepened by erosion. But Yin has now found evidence for a completely different process.
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