Examination of Interplanetary Dust Particles Collected from Antarctic Air
Abstract
Interplanetary dust particles (IDPs) are among the most fine-grained extraterrestrial objects available for study in the lab, and many are composed of primitive materials that have experienced very little alteration or processing since their formation early in solar system history [1]. The stratospheric collection of IDPs has provided a scientifically valuable sample set, but requires significant advanced planning and can be difficult to coordinate with specific cometary or asteroidal dust streams. Filtering of air from the Clean Air Sector near South Pole Station in Antarctica, however, can be done continuously, with regular changing of filters and no need for a viscous collection medium or melting of large volumes of snow and ice [2].
We have focused on small regions of two filters exposed during Antarctic summer and winter. Using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), we have identified a number of candidate IDPs for further analysis. Several of these grains are Fe-free, Mg-silicates consistent with an extraterrestrial origin, while others are more similar to bulk chondritic compositions. One of these candidate IDPs (Figure) is dominantly carbonaceous but with a few individual silicate grains and some elongate grains that could be enstatite "whiskers," a feature associated with these primitive materials [3]. This is reminiscent of ultracarbonaceous micrometeorites, thought to be cometary in origin [4]. We prepared several candidate grains for analysis in the scanning transmission electron microscope (STEM) using focused ion beam microscopy (FIB). The composition of each sample was analyzed using EDS, while oxidation state, carbon speciation, and volatile contents of vesicles were analyzed using electron energy loss spectroscopy (EELS). H and N isotopic measurements will provide further information about the source of this grain. [1] Bradley, J.P. (2007) In: Treatise on Geochemistry. 1-24. [2] Taylor, S., et al. (2017) LPSC 2024. [3] Bradley, J.P., et al. (1983) Nature, 301, 473. [4] Duprat et al. (2010) Science 328, 742.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P53G3070B
- Keywords:
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- 0406 Astrobiology and extraterrestrial materials;
- BIOGEOSCIENCESDE: 1028 Composition of meteorites;
- GEOCHEMISTRYDE: 3662 Meteorite mineralogy and petrology;
- MINERALOGY AND PETROLOGYDE: 5215 Origin of life;
- PLANETARY SCIENCES: ASTROBIOLOGY