用放射化学中子活化方法研究陨石中的Os和Ru同位素丰度

STUDY ON ISOTOPIC ABUNDANCE OF OSMIUM AND RUTHENIUM IN METEORITES BY RNAA

摘要: 选择南丹、邕宁铁陨石经2mol/l H_2SO_4处理后的残渣,和吉林、洮南石陨石的金属相部分,以Os、Ru试剂(地球同位素丰度)为标准,用放射化学中子活化方法测定~(190)Os/~(184)Os及~(96)Ru/~(102)Ru的比值。实验全面考虑了在照射、分离、测量过程中各种因素对Os和Ru同位素丰度测定的影响。对~(190)Os/~(184)Os的测量统计误差可控制在1％以内。实验结果表明,这4种陨石的~(190)Os/~(184)Os和~(96)Ru/~(102)Ru的比值与地球标准相比,不存在统计上有意义的同位素丰度比异常。
- 陨石 /
- Os /
- Ru /
- 同位素丰度 /
- 放射化学中子活化
Abstract: The ratios of 190Os/184Os and 96Ru/102Ru for the residues of the Nadan and the Yongning iron meteorites, as well as for the metal phases of the Jilin and the Taonan stone meteorites,are determined by RNAA. Before that,Nandan and Yongning iron meteorites are pretreated by dissolution in 2 mol/1 H2SO4. All factors affecting Os and Ru isotopic abundances during the processes of irradiation,separation and measurement have been taken into consideration. The statistical errors of measurement for the ratio of 190Os/184Os can be controlled to be less than 1%. The experimental results indicate that the statistically significant anomalies affecting isotopic 190Os/184Os and 96Ru/102Ru abundance have not been found relative to commercial Os and Ru chemicals.

[1]	Goel P S,Murty S V S. Presolar Grains in Microinclusions of Iron Meteorites. Adv Space Res, 1983, 2(12) : 13．
[2]	Goel P S. Variable ~(190) Os/~(184) Os Ratio in Acid Residues of Iron Meteorites. Proc Indian Acad Sci (Earth Planet Sci), 1987,96(2) :81．
[3]	Anders E,Grevesse N. Abundances of Elements: Meteoritic and Solar. Geochim Cosmochim Acta, 1989, 53: 197．
[4]	Weast R C,Astle M J,Beyer W H. CRC Handbook of Chemistry and Physics. 67th Edition. Boca Raton,Florida:CRC Press,Inc. 1986． B377．
[5]	欧阳自远,佟武,周景良.三块铁陨石的矿物成分及形成条件的研究.地质科学,1964,(3) :241．
[6]	王道德,麦尔文D J,沃森J T.中国某些铁陨石的化学分类.地球化学,1983,(2) :109．
[7]	柴之芳,海尔.用无同位素载体放射化学分离活化分析法测定~(184) Os/~(190) Os比值.分析化学,1986,14(2) :124．
[8]	欧阳自远.天体化学.第1版.北京:科学出版社,1988． 226．
[9]	Ryan D E,Holzbecher J,Brooks R R. Rhodium and Osmium in Iron Meteorites. Chemical Geology, 1990, 85: 295．
[10]	Pernicka E. Wasson J T. Ru, Re,Os, Pt and Au in Iron Meteorites. Geochim Cosmochim Acta, 1987, 51: 1717．
[11]	Chai Zhifang. Neutron Activation Analysis of Platinum Group Elements as Indicators of Extraterrestrial Materials. Isotopenpraxis, 1988, 24 (7) : 257．
[12]	Begemann F. Isotope Abundance Anomalies and Early Solar System (Some) Facts and (Some) Implications. Prog Part Nucl Phys, 1986, 17: 349．