Martian Tectonics?

Planetary geologists generally argue plate tectonics have not played a significant role in the history of Mars. They say that Mars is simply not massive enough to maintain a hot core over geologic time. Without a hot core, there can be no molten mantle open which tectonic plates can float and roam and slam into each other.

As is usual in science, however, not everyone agrees. A new study of a previously unexplored area not far from the huge volcano Olympus Mons, for example, shows ridges and scarps consistent with plate tectonics. Strings of volcanoes on Mars suggests a plate passing over a "hot spot," building volcanoes as it moved, much like the Hawaiian Islands were built up, and are still developing. Some scientists see Valleris Marineris, the incredibly huge canyon system on Mars, as a classic tectonic formation. The new study also suggests plate tectonics were active on Mars within the last 250,000 years-- and may be even today.

It's a controversial position, one sure to be vigorously debated. If the question of an active planet comes down to mass, after all, we know Mars is only about 11 percent as massive as Earth. However, if it turns out that plate tectonics can be maintained on a low gravity terrestrial world with less inner fire than Earth has. our understanding of the universe will have taken another step forward.