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

Abstract

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~80À140 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 À2 yr À1 near Maitri station.

Micrometeorite collections: a review and their current status

“…Similarly, the Cap-Prudhomme collection comprises over 1 00 000 micrometeorites extracted from ice formed in pre-industrial times –50 000 years ago [49]. The potential of melting many tonnes of Antarctic ice to find large numbers of micrometeorites is further demonstrated by the recent establishment of the Maitri collection, in which almost 3000 samples have already been classified [83]. The use of a suction-based collector or metal sieves to collect and prepare sediment, however, induces mechanical stress on dust particles.…”

Chemical compositions of Fe‐rich relict olivines from cosmic spherules, understanding their links with ordinary and carbonaceous chondrites

“…Cosmic spherules examined in this study were obtained from DSS of the Indian Ocean and Antarctic ice that were collected near the Indian base Maitri Station (Prasad et al., 2013; Rudraswami, Fernandes, et al., 2020). For DSS, the sediment was sampled from a water depth of ~5000 m and recovered using a grab sampler (Prasad et al., 2013).…”

“…In addition to this, ~1% of AMM and DSS spherules are chromite‐bearing cosmic spherules, of which nearly 70% are shown to support ordinary chondritic provenance (Rudraswami et al., 2019). Moreover, the textures of chondritic igneous objects, such as barred olivine and radial pyroxene in cosmic spherules, are comparable to the chondrules of many ordinary chondrites (Engrand et al., 2005; Fernandes, Rudraswami, & Pandey, 2021; Genge et al., 2005, 2008; Kurat et al., 1996; Prasad et al., 2018; Rudraswami, Fernandes, et al., 2020; Taylor et al., 2008, 2012). Relict components related to ordinary chondrites in cosmic spherules may be poorly characterized, concealed within the changes these particles undergo during atmospheric entry heating.…”

“…Micrometeorites are tiny extraterrestrial particles accumulated on the Earth's surface, ranging in size from tens of μm to a few mm. According to various studies (Brownlee et al., 1993; Maurette et al., 1991; Prasad et al., 2013; Rudraswami, Fernandes, & Pandey, 2020; Taylor et al., 1998; Yada et al., 2004), they are thought to originate from asteroid collisions and comets sublimation that injected large amounts of dusty material into space, which can be directed by P‐R drag into the Earth's resonant orbit (Dohnanyi, 1967). This process injects an estimated 30,000 t of extraterrestrial dust annually into the Earth's upper atmosphere (Love & Brownlee, 1993).…”

“…In comparison, the ground‐based estimates of extraterrestrial dust indicate ≤10% survives as micrometeorites (MMs) that can be recovered from Antarctic ice, DSSs, fossil rocks, etc. (Meier et al., 2010; Onoue et al., 2011; Plane, 2012; Prasad et al., 2013; Rudraswami, Fernandes, et al., 2020; Rudraswami, Prasad, Dey, Plane, et al., 2016; Suttle & Genge, 2017; Taylor et al., 1998, 2000; Tomkins et al., 2016).…”