Probing the nature of extraterrestrial dust reaching the Earth’s surface collected from the Maitri station, Antarctica

N. G. Rudraswami, D. Fernandes, M. Pandey

Meteoritics & Planetary Science
Version of Record online: 04 October 2020


“Micrometeorites (MMs) are extraterrestrial dust particles, in the size range of tens of µm to mm, recovered from the Earth’s surface primarily from deep‐sea sediments, Antarctica, and also from space. The present collection of MMs (>50 µm) obtained by melting ~50 t of ice near the Maitri station, Antarctica, has allowed us to investigate the abundance and properties of the particles by an unbiased collection technique. The collection reveals a large quantity of extraterrestrial material in the ~80−140 µm size range. Previous collections have shown an abundance of particles at diameter ~200 µm, which is in contrast to our findings. This can either be explained by movement of material within the ice or a recent influx of smaller particles. The smaller particles (<80 µm) typically undergo atmospheric entry heating, contrary to earlier observations, which have suggested that they reach the Earth’s surface unmelted. Chondrules and refractory inclusions are rare in the collected MMs indicating that their contribution is only a small percentage. The Maitri station collection does not have a well‐constrained ice accumulation rate and terrestrial age. Nevertheless, based on matching the previous well‐documented flux calculation of Antarctica, we suggest a slow ice accumulation rate of <1.0 g cm−2 yr−1 near Maitri station.”