The boron concentrations in 13 Antarctic meteorite specimens were published in 1988 (1). Here we report B, Sm, Gd, and some H abundances in 27 additional chondrites and 14 achondrites, all measured by prompt gamma neutron activation analysis: some Li analyses were also made, using AAS. The accuracy and precision of analysis are particularly important for B, Sm, and Gd, whose abundance levels in meteorites can be 1 ppm or less, so multiple analyses of Reference Materials DTS-1, PCC-1, BHVO-1, and JG-1 were made for controls. The results showed good agreement with recommended values for B and H (expressed as H2O); the results were good also for Sm and Gd but at concentrations 10x meteorites. Precision was adequate, averaging 10 to 15% (1 s.d.) of amount present. Stringent precautions against contamination were maintained during handling and analysis. Natural mobilisation of B in the Antarctic weathering environment is however known to take place (1). The summarised results are as follows: B Sm Gd H2O Li ppm ppm ppm % ppm Mean of 6 analyses of 3 C.C. 0.93 0.36 0.39 0.94 4.3 Mean of 42 analyses of 37 CH 0.78 0.35 0.30 0.97 5.8 Mean of 7 eucrites, howardites 2.7 1.1 1.9 0.75 - The principal observations are that (a) B and Li abundances in CH and C.C. resemble earlier estimates, (b) Sm and Gd in CH and C.C. are markedly higher than expected, (c) B, Sm, and Gd are significantly higher in eucrites and howardites than in other meteorites (including aubrites, diogenites, and ureilites) and (d) estimates of H2O on individual meteorites agree quite well with published results by conventional methods. These observations form the basis for further interpretations. (1) D. M. Shaw, M. D. Higgins, R. W. Hinton, M. G. Truscott, and T. A. Middleton (1988) Boron in chondritic meteorites. Geochimica et Cosmochimica Acta 52, 2311-2319.
- Pub Date:
- July 1992