MAGNETIC-PROPERTIES EXPERIMENTS ON THE MARS PATHFINDER LANDER - PRELIMINARY-RESULTS

Many of the particles currently suspended in the martian atmosphere ar e magnetic, with an average saturation magnetization of about 4 A.m(2) /kg (amperes times square meters per kilogram). The particles appear t o consist of claylike aggregates stained or cemented with ferric oxide (Fe2O3); at least some of the stain and cement is probably maghemite (gamma-Fe2O3). The presence of the gamma phase would imply that Fe2+ i ons leached from the bedrock, passing through a state as free Fe2+ ion s dissolved in liquid water. These particles could be a freeze-dried p recipitate from ground water poured out on the surface. An alternative is that the magnetic particles are titanomagnetite occurring in palag onite and inherited directly from a basaltic precursor.