Projection of MOLA data of Martian north pole to equator.
Black lines indicate position interpreted shorelines.
In a paper published in Thursday's issue of the journal Nature, planetary scientists at the University of Arizona and MIT said that features in images of the planet previously thought to be remains of ancient shorelines are more likely linked to the planet's volcanoes. Evidence for those ancient shorelines, also called paleoshorelines, was published in late 1999. Those features included smooth, flat boundaries between geological units and a series of terraces parallel to the shorelines that could be explained by receding shorelines. Those findings seemed to confirm models of an early Mars that was warmer and wetter than the present day. Some scientists believe that the northern plains of the planet, whose low elevation and flat topology closely resembles an ocean basin, could have been submerged under an ocean early in the planet's history, when liquid water could exist on the surface.