Magnetic lineations in the ancient crust of Mars

The Mars Global Surveyor spacecraft, in a highly elliptical polar orbit, ob tained vector magnetic field measurements above the surface of Mars (altitu des >100 kilometers). Crustal magnetization, mainly confined to the most an cient, heavily cratered martian highlands, is frequently organized in east- west-trending linear features, the Longest extending over 2000 kilometers. Crustal remanent magnetization exceeds that of terrestrial crust by more th an an order of magnitude. Groups of quasi-parallel linear features of alter nating magnetic polarity were found. They are reminiscent of similar magnet ic features associated with sea floor spreading and crustal genesis on Eart h but with a much Larger spatial scale. They may be a relic of an era of pl ate tectonics on Mars.