Microanalyses of antarctica micrometeorites

• Published in: Proceedings, annual meeting, Electron Microscopy Society of America
• Main Authors: Maurette, M., Perreau, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1992
• Subjects: General Medicine; Antarctic; The Antarctic; Dumont d'Urville; Dumont-d'Urville; Antarc*; Antarctica; Ice Sheet
• Online Access: http://dx.doi.org/10.1017/s0424820100133217; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0424820100133217

About 260 tonnes of ultraclean blue ice were recently melted and filtered on the Antarctic ice sheet (in January 1991, at Cap-Prudhomme, near the french station of Dumont d'Urville) as to collect all grains with sizes > 25 μm. In the best size fraction (50-100μm) about 10% of the grains are unmelted antarctic micrometeorites (AMMs) with a chondritic composition. About 50% of these grains are complex aggregates of submicron-sized grains. Their characterization, which is very difficult, requires a panoply of analytical techniques allowing their analyses at all scales of magnification between 10 6 μm 3 and 10 -4 μm 3 . We review below analyses performed by various groups, and discuss briefly some of their preliminary implications to various fields of Science. The "large" size of the AMMs allows their multidisciplinary investigations. With a binocular we start selecting an aliquot of ≈50 dark grains showing irregular shapes, and which usually contains about 70% AMMs. Each grain is broken into about 4 fragments and their multidisciplinary analysis proceeds as follow: (1) Polished sections . The largest of these fragments are mounted in an epoxy disc and polished.