NEW DATA ON THE ABUNDANCE OF PALLADIUM IN METEORITES

The concentration of Pd in 7 carbonaceous chondrites, 18 ordinary chondrites, 3 achondrites, 29 iron meteorites and other samples has been determined by stable isotope dilution using solid source mass spectrometry. The Cl chondrite Orgueil gives a 'cosmic' abundance for Pd of 1.5 (Si = 106 atoms), in good agreement with the currently accepted value. The concentration of Pd shows little variation among the carbonaceous chondrites, but in ordinary chondrites decreases from the H to L to LL groups. Pd in achondrites is approx 100 times lower than in chondrites. Data for iron meteorites plot around the 'cosmic' Pd Ni ratio; however the Pd data falls into distinct groups, corresponding to the chemical group classification. These results support the hypothesis that at least two fractionation processes have occurred during the formation of iron meteorites. © 1979.