Mineralogic Evidence for an Impact Event at the Cretaceous-Tertiary Boundary

@article{Bohor1984MineralogicEF,
  title={Mineralogic Evidence for an Impact Event at the Cretaceous-Tertiary Boundary},
  author={B. F. Bohor and E. Foord and P. J. Modreski and D. Triplehorn},
  journal={Science},
  year={1984},
  volume={224},
  pages={867 - 869}
}
  • B. F. Bohor, E. Foord, +1 author D. Triplehorn
  • Published 1984
  • Geology, Medicine
  • Science
  • A thin claystone layer found in nonmarine rocks at the palynological Cretaceous-Tertiary boundary in eastern Montana contains an anomalously high value of iridium. The nonclay fraction is mostly quartz with minor feldspar, and some of these grains display planar features. These planar features are related to specific crystallographic directions in the quartz lattice. The shocked quartz grains also exhibit asterism and have lowered refractive indices. All these mineralogical features are… CONTINUE READING
    263 Citations

    Topics from this paper

    Glass from the Cretaceous/Tertiary boundary in Haiti
    • 170
    • PDF

    References

    SHOWING 1-6 OF 6 REFERENCES
    Bohor, paper presented at the 20th Annual Meeting of the Clay
    • Minerals Society,
    • 1983
    ] makes a case for concentration of iridium in marine clays at the K-T ues for iridium of 5
    • Geol. Soc. Am. Spec. Pap
    • 1982
    Gratz for their helpful comments; and C. Sanderson for laboratory assistance