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The addition of meteoritic material to the Mars soils should perturb their chemical compositions, as has been detected for soils on the Moon [Anders et al., 1973] and sediments on Earth [Kyte and Wasson, 1986]. Using the measured mass influx at Earth and estimates of the Mars/Earth flux ratio, we estimate the continuous, planet‐wide meteoritic mass influx on Mars 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 [Christensen, 1986], our 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 is inconsistent with typical basaltic rock fragments but can be fit by a mixture of 60% basaltic rock fragments and 40% meteoritic material [Clark and Baird, 1979]. The meteoritic influx we calculate 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 60–200 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]. On Earth atmospheric entry all but the smallest particles (generally ≤ 50 μm in diameter) in the 10−7 to 10−3 g mass range are heated sufficiently to melt or vaporize. Mars, because of its lower escape velocity and larger atmospheric scale height, is a much more favorable site for unmelted survival of micrometeorites on atmospheric deceleration. We calculate 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.
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