[MissAmericanPie]

Could this top layer of sand be space dust? Accumulated over millions of years? I know it's said that the top layer of dust on the moon is space dust and is about the same depth as this is on Mars.

[Aracelis]

About 40,000 tons of ~0.2 mm micrometeorites fall to Earth every year. I would imagine Mars is exposed to a similar amount, yet I doubt that the surface of Mars is dominated by this influx of material. Remember, Mars has an atmosphere that is dynamic. Most of what we are seeing is likely sediments blasted from existing rock during sandstorms.