Measurement on He and Ar Isotopic Compositions in Solid Samples by Mass Spectrometry
-
摘要: 在现有设备的基础上，经多年实验，以空气Ｈｅ、Ａｒ同位素作标准样，采用同位素峰高比分析方法，在国内首次建立了一次进样完成固体样品中Ｈｅ、Ａｒ同位素的测量技术。文中就该项技术的要点，包括样品的前期处理、空气标准样的使用、仪器空白与灵敏度的测定、固体样品进样量的估算方法、测量条件等予以说明与分析。对应用该项技术获取的固体样品中Ｈｅ、Ａｒ同位素首批数据及其偏差，文中也进行了讨论。该项技术方法的建立，将为与惰性气体同位素相关的研究领域提供新的实验技术支撑，推动相关领域基础研究的开展和水平的提高。Abstract: An analytical technique for the simultaneous determination of He and Ar contents and isotopic tom-positions in rocks by static mass spectrometer has heen developed. The gases in rocks are extracted bymelting at 1 600℃.The purification of noble gases、an be made out by。titanium sponge Better at600℃，two Zr-Al Betters, and a Ti subliming Better. Heavier noble gases, such as argon, krypton andxenon are absorbed in a charcoal trap held at liquid nitrogen temperature. The purified helium and neonfractions are admitted to the mass spectrometer for helium measurement. After that, pumping out the Heand Ne, the charcoal trap is heated, and then the released(Ar+ Kr+ Xe)fractionis admitted to the massspectrometer for argon measurement. The air with constant isotopic compositions of noble gases is con-sidered as a standard sample. The average sensitivities of4He，20Ne and 36 Ar are(9. 00 +0.35）×10-10，(1. 4 01+0. 03 2）×10 -9 and(1. 76+0. 21）×10-10 cm3 STP,respectively. The blank levels of the sys-tem fo r4He and 36Ar are 1. 3860 ×109 and 4. 08×10-11cm3STP, respectively. Measured He and Ar con-tents and isotopic compositionsinedogites are given in this paper. Itis the first report on He and Arisotopic compositions in rocks in China.
-
Key words:
- rock sample /
- He Ariso to pes /
- measurement of mass spectrometer
-
[1] 1 Allegre C,J, Staudacher Th and Sanla Ph. Rare gas systemat-ics formation of the atmosphere, evolution and structure of theearth's mantle. Earth Planet Sci Lett, 1986/1987, 81 127--150
2 Li B and Manuel Q K. A noble gas technidue for the identifi-canon of mantle and crustalmaterials and its application to theKuroko deposits. Geochem J, 1994, 28 47- 69.
3 叶先仁孙明良.地球岩石中稀有气体研究进展.地球科学进展.1997, 12( 2): 118- 126.
4 Hlton D R. Hammerschmidt K and Teufel Setal. Heliumiso一tope characteristics of Andean geothermal fluids and lavas.Earth Planet Sci Lett, 1993, 120 265- 282.
5 Pyle D M. Graphical analysis of rare gas mixing systematics ingeothermal systems Geochem J, 1993, 27 125- 129.
6 Polvak B G, Prasolov E M and Tolstikhin 1 N et al. Heliumisotopes in fluids of the Baykal Rift Gone. lntGeo 1Rev.1993.35( 2): 186-202.
7 W aki to H. San o Y and L rube Aetal. Origin of methane-richnatural gas in,Japan formation of gas fields due to large-scalesubmarine volcanism. Appl Geochem, 1990, 5(3): 263- 278
8 Weise S M, Drescher,J and Schafer Ketal. Gas compositionand noble gas isotope-dlerived model ages. Scientific Drilling,1995.(5): 111-118.
9 Hunan B B and Graham D W. Lead and helium isotope evi-dence from oceanic basalts for a common deep source of man-tle plum es. Science, 1996, 272 991-995.
10 Hilton D R.Hammerschmidt K and Loock Get al. Heliumand argon isotope systematics of the central Lau Basin andValu Fa Ridge Evidence of crust /mantle interactions in aback-arc basin. Geochim Cosmochim Acta, 1993, 57 2819-2841.
11 Staudacher Th and Allegro C,J. Theorigin of josephinites anew noble gas study. Earth Planet Sri Lett, 1990, 98 380-389.
12 Ozima M and Zahnle K. Mantle degassing and atmosphericevolution Noblegas view Geochem,J, 1993,22 185- 200.
13 Lupton,J Et A far-field hydrothermal plume from Loihi searnount. Science, 1996, 272 976-979.
14 孙明良稀有气体同位素测量与V G-5 400质谱计的特点.中国科学院兰州地质研究所生物气体地球化学开放研究实验室研究年报(1986).兰州:甘肃科学技术出版社.1986,. 246一250.
15 王先彬稀有气体同位素地球化学和宇宙化学.北京:科学出版社.1989.
16 孙明良徐永昌.王先彬天然气中氦同位素的质谱分析.分析测试通报.1991, 10(5): 50- 55.
17 孙明良孔庆云.微量气体中氦同位素的质谱峰高比测定法.兰州人学学报(自然科学版).1989, 25( 4): 124- 128. -
点击查看大图
计量
- 文章访问数: 485
- HTML全文浏览量: 7
- PDF下载量: 426
- 被引次数: 0
下载:
