Stable isotope dilution analyses of molybdenum in meteorites

Isotope dilution mass spectrometry is an ideal analytical technique to meas ure the elemental abundance of Mo in C1 carbonaceous chondrites and the met allic and troilite phases of iron meteorites. The mean abundance of Mo in t wo C1 meteorites is 0.909 +/- 0.040 mu g/g which corresponds to a value of 2.55 atoms Mo with respect to Si equal to 10(6) atoms, which is identical t o the currently accepted solar system abundance. The partitioning of Mo bet ween the metallic and sulfide phases in the Mundrabilla iron meteorite was found to be 6.0 +/- 0.2 mu g/g and 8.6 +/- 0.3 mu g/g, respectively. A new, precise Mo concentration of 1.54 +/- 0.04 mu g/g for the Geochemical Refer ence Standard BCR-1 is also reported.