Meteorite accumulations on Mars

We have modeled single-body meteoroid atmospheric entry speeds at Mars and the effect of drag and ablation, and identify a narrow range of small masse s (10-50 g) that should impact Mars at survivable speeds. The rate of oxida tive weathering is much lower than that on Earth, so this small flux of met eorites could give rise to significant accumulations: ca. 5 x 10(2) to 5 x 10(5) meteorites greater than 10 g in mass per square kilometer. Given that extremely large numbers of meteorites may be present on Mars, future sampl e-return missions should consider the real possibility that they may recove r meteoritic material. Due to the low weathering rate, meteorites may survi ve on the surface of Mars for more than 10(9) years, preserving a record of the temporal variability of the meteoroid flux and the compositional evolu tion of the meteoroid complex. Intact carbonaceous chondrites may also pres erve organic compounds from degradation by ultraviolet radiation. Terrestri al meteorites may be present, but would probably be sterile. (C) 2000 Acade mic Press.