Volcanism on Mars

Abstract

One of the earliest and most significant of the Mariner 9 results was the recognition of prominent volcanic features on Mars. The volcanic features have a markedly asymmetric distribution. The planet can be roughly divided into two hemispheres. One includes nearly all the central volcanic features and the sparsely cratered plains; the other, for the most part, is densely cratered terrain, superficially resembling the lunar highlands.