Access

News and Views

Nature Geoscience 2, 7–8 (1 January 2009) | doi:10.1038/ngeo401

Planetary Science: Mars's rotating shell

Francis Nimmo

On a global map of Mars, two features stand out: the northern hemisphere is lower and smoother than the southern one, and the western hemisphere contains a massive volcanic construct — the Tharsis Rise — that straddles the equator. Both features are ancient, more than four billion years old, but the Tharsis region is the younger of the two and volcanism here decreases in age from the south to the north.