Mass spectrometric isotope dilution analyses of palladium,silver, cadmium and tellurium in carbonaceous chondrites |
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| Authors: | Robert D Loss Kevin JR Rosman John R De Laeter |
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| Institution: | Department of Applied Physics, Western Australian Institute of Technology, Bentley, Western Australia, 6102 |
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| Abstract: | The mass spectrometric isotope dilution technique was used to measure the elemental abundances of Pd, Ag, Cd and Te in Orgueil (C1), Ivuna (C1), Murray (C2) and Allende (C3) chondrites. The Pd abundance of 554 ppb for the C1 chondrites is almost identical to the recommended value of Anders and Ebihara (1982); that for Cd (712 ppb) is approximately 5% higher, whereas that for Ag (198 ppb) is approximately 10% lower than the recommended values. A smooth distribution for the abundances of the odd-A nuclides between65 ≦ A ≦ 209 have been observed except for small irregularities in the Pd-Ag-Cd and the Sm-Eu mass regions (ANDERS and Ebihara, 1982). The results from the present work have the effect of smoothing out the dip in the Pd-Ag-Cd region and indicate that there is no systematic fractionation of cosmochemical element groups in this mass region.A Te abundance of 2.25 ppm has been determined for the C1 chondrites Orgueil and Ivuna in agreement 2+with the value of Smith et al. (1977). This value is some 30% lower than the value of Krähenbühl et al. (1973) but is in good agreement with the more recent measurements from Chicago. The Krähenbühl et al. value causes 128Te and 130Te to lie approximately 30% above the r-process peak at A = 130 (Käppeler el al., 1982), whereas the new value fits smoothly into the general trend. |
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