干旱区生态环境知识资源中心

Discovery of a large number of meteorites from the Grove Mountains (GRV) region, Antarctica, demands a non-destructive and efficient method of classifying meteorites. Magnetic susceptibility (chi) of meteorites was mainly contributed by metallic Fe-Ni, hence a potentially important criterion of classification of meteorites. In addition, magnetic susceptibility is a fundamental parameter of meteorites. In this paper we report the first measurements of magnetic susceptibility of Grove Mountains meteorites. Experiments on simulation samples demonstrated that deviation of magnetic susceptibility measurement due to various sizes and shapes of the samples is less than 1%, within the analytical precision. Magnetic susceptibility of the first classified 613 Grove Mountains meteorites was measured, including martian meteorites, eucrites, carbonaceous chondrites, ureilites, mesosiderites and pallasite. Most ordinary chondrites of H, L and LL groups can be classified according to magnetic susceptibility. Moreover, magnetic susceptibility is more reliable for classification of unequilibrated ordinary chondrites. The distribution pattern of magnetic susceptibility of H-group of Grove Mountains meteorites is nearly identical to that of other Antarctic meteorites, both with the mass normalized magnetic susceptibility (log chi, 10(-9) m(3)/kg) lower by 0.2 than that of meteorite falls, indicative of terrestrial weathering effects of Grove Mountains meteorites. Magnetic susceptibility of L-group of Grove Mountains meteorites also shifts to lower values by 0.2 as H-group. In contrast, L-group of other Antarctic and desert meteorites shows scattered distribution patterns, probably indicative of various weathering degrees.