A SYNTHESIS OF TRIPLE-OXYGEN ISOTOPE ANALYSES ON ANTARCTIC MICROMETEORITES

Micrometeorites (MMs) are extraterrestrial dust particles ranging in size between 10 μm and 2 mm [1], which form the main part of the extraterrestrial flux to Earth ~40000 tons/year) [2]. Traditionally, MMs have been recovered from a variety of environments including deep-seas, deserts, lakes and by melting large of Antarctic ice or snow [3-5]. Over the last decade, large and fresh accumulations of MMs have been discovered in sediment traps on top of glacially eroded granitic summits in the Transantarctic Mountains [6]. Similar deposits have also been found during the 2012-2013 Belgian-Japanese MICROMETA expedition in the Sør Rondane Mountains (East Antarctica), and are currently under investigation. Due to differential production and transportation mechanisms, these microscopic particles of the near-Earth dust complex sample parent bodies different from those of meteorites [7-9]. Oxygen ratios are one of the most powerful diagnostic tools to determine the origin of extraterrestrial material, because the combined mass-dependent and mass-independent effects on the three isotopes (16O,17O, and 18O) are well known [10]. Mass-dependent and mass-independent effects during the atmospheric entry of micrometeoroids predominantly reflect fractionation (i.e. from a single source) or mixing of two or more sources (e.g., between nebular reservoirs or with terrestrial oxygen), respectively. Here we present an overview of the available oxygen isotopic data from literature and briefly discuss how the application of SHRIMP-SI (Sensitive High-Resolution Ion Microprobe – Stable Isotope) may facilitate the identification of MM parent bodies.