Terrestrial Age Measurement of Antarctic Meteorites

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Nishiizumi 9316272 This award supports a project to measure 36Cl and 41Ca in Antarctic meteorites in order to estimate terrestrial ages of the meteorites. This work is a collaborative effort between the University of California, Berkeley, and the Lawrence Livermore National Laboratory. When combined with other chemical and isotopic data on the meteorites, the terrestrial ages allow inferences about solar system history and orbital trajectories of the meteorites prior to collision with Earth. The terrestrial ages are also valuable for glaciological studies of the Antarctic ice sheet, or geomorphological studies of the ice-free areas, on which the meteorites are found. For ice sheets, they provide an estimate of the time that the ice sheet has been concentrating debris and ice in the particular ablation region in which the meteorite is found. This information is useful input to dynamic models of the ice sheet. For ice-free regions, the meteorites, provide an estimate of the antiquity of the geomorphic surface. In conjunction with exposure ages, the terrestrial ages provide useful information about past glaciation of the presently ice- free areas. The terrestrial ages that this work will produce represent a useful investment in baseline data for research in geomorphology and glaciology.