An assessment of the meteoritic contribution to the Martian soil

Using the measured mass influx at Earth and estimates of the Mars/Earth flux ratio, the continuous, planet-wide meteoritic mass influx on Mars is estimated to be between 2700 and 59 000 t/yr. If distributed uniformly into a soil with a mean planetary production rate of 1 m/b.y., consistent with radar estimates of the soil depth overlaying a bouldered terrain in the Tharsis region, the estimated mass influx would produce a meteoritic concentration in the Mars soil ranging from 2 to 29% by mass. Analysis of the Viking X-ray fluorescence data indicates that the Mars soil composition can be fit by a mixture of 60% basaltic rock fragments and 40% meteoritic material. [Clark and Baird, 1979]. The meteoritic influx calculated is sufficient to provide most or all of the material required by the Clark and Baird [1979] model. Particles in the mass range from 10^-7 to 10^-3 g, about 60-1200 μm in diameter, contribute 80% of the total mass flux of meteoritic material in the 10^-13 to 10⁶ g mass range at Earth [Hughes, 1978]. It is calculated that a significant fraction of particles throughout the 60-1200 μm diameter range will survive Mars atmospheric entry unmelted. Thus returned Mars soils may offer a resource for sampling micrometeorites in a size range which is not collectable in unaltered form at Earth. -from Authors