Chinese Science Bulletin

, Volume 47, Issue 2, pp 150–153 | Cite as

FeO-rich silicates and Ca, Al-rich inclusions in Qingzhen and Yamato 691 (EH3) meteorites: Evidence for migration of mass in the solar nebula

  • Yangting Lin
  • Ziyuan Ouyang
  • A. El Goresy
Notes
  • 25 Downloads

Abstract

The Qingzhen and Yamato 691 (EH3) enstatite chondrites, which formed under extremely reducing conditions, are studied using the scanning electron microscope and electron probe microanalyzer. Both meteorites contain FeO-rich silicates and minor Ca, Al-rich inclusions. Most FeO-rich silicates are Ca-poor pyroxenes and occur as fragments in matrix. A few grains of FeO-rich silicates were found in chondrules, and FeO-rich olivine is rare. In Qingzhen, FeO-rich silicates commonly contain abundant dust-like Ni-poor metals, which probably formed through reduction of FeO. In contrast, only a few fragments of FeO-rich silicates in Yamato 691 enclose dust-like metals. This difference is consistent with a more reducing condition of Qingzhen than Yamato 691. Ca, Al-rich inclusions have similar modal compositions and mineral chemistry as their counterparts in carbonaceous chondrites. We suggest that (1) the FeO-rich silicates probably formed in oxidized regions of the solar nebula, and then moved into the enstatite chondrite locations; and (2) Ca, Al-rich inclusions in both enstatite chondrites and carbonaceous chondrites may have similar origins and reservoirs.

Keywords

solar nebula meteorite enstatite chondrite reduction migration 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Lin, Y., El Goresy, A., Ouyang, Z. et al., Petrographical and mineralogical study of opaque minerals in the Qingzhen enstatite chondrite (EH3) Geochem (in Chinese)., 1995, 24: 76.Google Scholar
  2. 2.
    Ehlers, E., El Goresy, A., Normal and reverse zoning in niningerite: A novel key parameter to the thermal histories of EH-chondrites, Geochim Cosmochim Acta, 1988, 52: 877.CrossRefGoogle Scholar
  3. 3.
    Rambaldi, E. R., Housley, R. M., Rajan, R. S., Occurrence of oxidized components in Qingzhen enstatite chondrite, Nature, 1984, 311: 138.CrossRefGoogle Scholar
  4. 4.
    Bischoff, A., Keil, K., Stöffler, D., Perovskite-hibonite-spinelbearing inclusions and Al-rich chondrules and fragments in enstatite chondrites, Chem Erde., 1985, 44: 97.Google Scholar
  5. 5.
    Fagan, T. J., Krot, A. N., Keil, K., FeO-rich silicates in EH3 and EL3 chondrites: Evidence for variations in redox conditions in enstatite chondrite-forming region? Lunar & Planet Sci., 1999, XXX: #1523.Google Scholar
  6. 6.
    Fagan, T. J., Krot, A. N., Keil, K., Calcium-aluminum-rich inclusions in enstatite chondrites (I): Mineralogy and textures, Meteorit Planet Sci., 2000, 35: 771.Google Scholar
  7. 7.
    Guan, Y., Huss, G. R., MacPherson, G. J. et al., Calcium-aluminum-rich inclusions from enstatite chondrites: indigenous or foreign? Science, 2000, 289: 1330.CrossRefGoogle Scholar
  8. 8.
    Kimura, M., Lin, Y., Hayegon, H., Unusually abundant refractory inclusions and FeO-rich silicates in an EH3 chondrite, Sahara 9 7159 (abstract), Meteorit Planet Sci., 2000, 35: A87.Google Scholar
  9. 9.
    Bence, A. E., Albee, A. L., Empirical correction factors for the electron microanalysis of silicates and oxides, J. Geol., 1968, 76: 382.CrossRefGoogle Scholar
  10. 10.
    El Goresy, A., Yabuki, H., Ehlers, K., et al., Qingzhen and Yamato-691: A tentative alphabet for the EH chondrites, Proc. NIPR Symp. Antarct. Meteorit., 1988, 1: 65.Google Scholar
  11. 11.
    Rambaldi, E. R., Rajan, R. S., Wang, D. et al., Evidence for relict grains in chondrules of Qingzhen, an E3 type enstatite chondrite, Earth Planet. Sci. Lett., 1983, 66: 11.CrossRefGoogle Scholar
  12. 12.
    Weisberg, M. K., Prinz, M., Fogel, R. A., The evolution of enstatite and chondrules in unequilibrated enstatite chondrites: Evidence from iron-rich pyroxene, Meteoritics, 1994, 29: 362.Google Scholar
  13. 13.
    Shu, F. H., Shang, H., Glassgold, A. E. et al., X-rays and fluctuating X-winds from protostars, Science, 1997, 277: 1475.CrossRefGoogle Scholar
  14. 14.
    Krot, A. N., Meibom, A., Russell, S. S. et al., A new astrophysical setting for chondrule formation, Science, 2001, 291: 1776.CrossRefGoogle Scholar
  15. 15.
    Guan, Y., McKeegan, K. D., MacPherson, G. J., Oxygen isotopes in calcium-aluminum-rich inclusions from enstatite chondrites: new evidence for a single CAI source in the solar nebula, Earth Planet. Sci. Lett., 2000, 181: 271.CrossRefGoogle Scholar
  16. 16.
    Fagan, T. J., McKeegan, K. D., Krot, A. N. et al., Calcium-aluminum-rich inclusions in enstatite chondrites (II): Oxygen Isotopes, Meteorit Planet. Sci., 2001, 36: 223.CrossRefGoogle Scholar

Copyright information

© Science in China Press 2002

Authors and Affiliations

  • Yangting Lin
    • 1
  • Ziyuan Ouyang
    • 2
  • A. El Goresy
    • 3
  1. 1.Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhouChina
  2. 2.Institute of GeochemistryChinese Academy of SciencesGuiyangChina
  3. 3.Max-Planck-Institut für ChemieMainzGermany

Personalised recommendations