TY - JOUR
T1 - Boron isotope ratios in meteorites and lunar rocks
AU - Zhai, Mingzhe
AU - Nakamura, Eizo
AU - Shaw, Denis M.
AU - Nakano, Toshio
N1 - Funding Information:
Acknowledgments--Financial support was provided by the Japan Society for the Promotion of Science and the Canadian National Science and Engineering Research Council. Lunar samples were made available by the NASA-JSC-Lunar Curating Center. Meteorite samples were supplied by several museum curators and are acknowledged individually in Zhai and Shaw (1994). Many thanks to Linda Wanless for improving the English of the first version. We thank Marc Chaussidon, Jesse Smith, Doug Macdougal, and an anonymous reader for helpful reviews.
PY - 1996/12
Y1 - 1996/12
N2 - The 11B/10B ratios of thirty-two meteorite falls and nine lunar rocks were measured as Cs2BO+2 using thermal ionization mass-spectrometry. The 11B/10B ratios of meteorites vary from 4.011 to 4.098, i.e., their δ11B values (relative to NIST SRM 951) range from -10.5 to +19.2‰; however, excluding two outliers, Mokoia and Norton County, the range of most meteorites is smaller (-10.5 to +7.5). The average of two CI1 meteorites, Ivuna and Orgueil, is -3.3, in the middle of the range. The δ11B values of the lunar rocks vary less than those of meteorites, from -6.0 to -3.9. The average δ11B of CI1 chondrites is -3.3, similar to that of terrestrial fresh mid-ocean ridge basalts (-6.5 to -1.2) and to the estimated mantle value of +0.2 (Ishikawa and Nakamura, 1992), which is the best representative of the whole Earth. The similarity of δ11B values in meteorites, lunar rocks, and those parts of the Earth unaffected by water implies that the boron isotopic composition of the Solar System is rather homogeneous. Recently, Chaussidon and Robert (1995) reported larger variation of δ11B values in chondrules of three chondrites, from -50 to +40. This degree of heterogeneity is absent from bulk meteorites.
AB - The 11B/10B ratios of thirty-two meteorite falls and nine lunar rocks were measured as Cs2BO+2 using thermal ionization mass-spectrometry. The 11B/10B ratios of meteorites vary from 4.011 to 4.098, i.e., their δ11B values (relative to NIST SRM 951) range from -10.5 to +19.2‰; however, excluding two outliers, Mokoia and Norton County, the range of most meteorites is smaller (-10.5 to +7.5). The average of two CI1 meteorites, Ivuna and Orgueil, is -3.3, in the middle of the range. The δ11B values of the lunar rocks vary less than those of meteorites, from -6.0 to -3.9. The average δ11B of CI1 chondrites is -3.3, similar to that of terrestrial fresh mid-ocean ridge basalts (-6.5 to -1.2) and to the estimated mantle value of +0.2 (Ishikawa and Nakamura, 1992), which is the best representative of the whole Earth. The similarity of δ11B values in meteorites, lunar rocks, and those parts of the Earth unaffected by water implies that the boron isotopic composition of the Solar System is rather homogeneous. Recently, Chaussidon and Robert (1995) reported larger variation of δ11B values in chondrules of three chondrites, from -50 to +40. This degree of heterogeneity is absent from bulk meteorites.
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U2 - 10.1016/S0016-7037(96)00338-9
DO - 10.1016/S0016-7037(96)00338-9
M3 - Article
AN - SCOPUS:0030426955
SN - 0016-7037
VL - 60
SP - 4877
EP - 4881
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
IS - 23
ER -