ALH-82102 - AN ANTARCTIC METEORITE EMBEDDED PARTLY IN ICE

We measured the concentrations of F, Cl, Br and I in two different ali quots of the meteorite ALH 82102. This H5 chondrite was recovered at t he Allan Hills region, while it was partially embedded in the ice. One aliquot was taken from that part of the surface of the meteorite that was still in the ice, and the other one was taken from the side, whic h was poking out of the ice. Both aliquots are highly, and nearly to t he same degree, contaminated with halogens. The observed enrichments o ccurred mainly during the time the meteorite was lying on the surface of the ice by deposition and/or adsorption of aerosols, salts, and gas eous components. A contamination during the time it was covered by the ice is unlikely. We conclude, therefore, that this meteorite was not always buried in the ice during its ''residence time'' on Earth. In or der to accumulate the observed contamination, it had to be on the surf ace of the ice part of the time between its fall onto the Earth and it s collection. The age of the ice surrounding the meteorite cannot be e qual to the measured terrestrial age of ALH 82102.