Abstract
STARTING with the discovery of an iridium anomaly at the Cretaceous/Tertiary boundary in Italy1, the idea that a large asteroid or comet struck the Earth at the end of the Cretaceous period has gained wide acceptance2ā4 although some workers suggest that massive volcanic eruptions can also explain the observations5. The abundance of small diamonds, 3ā5 nm in size, in chondritic meteorites6,7 prompted us to search for such diamonds in the Cretaceous/Tertiary boundary clay of the Red Deer Valley of Alberta (the 'Knudsen's farm' locality). Dissolution and oxidation of this clay yielded 45 ng gā1 of a white fraction, consisting of more than 97% carbon, which was absent from rocks above and below the boundary layer. We present evidence that this material is indeed diamond, which strengthens further the case for an extraterrestrial impact. The diamond/indium ratio in the boundary clay may constrain the type of impactor; our estimate (1.22:1) is close to the value found in type C2 chondritic meteorites2.
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References
Alvarez, L. W., Alvarez, W., Asarao, F. & Michel, H. V. Science 208, 796ā799 (1980).
Hut, P. et al. Nature 329, 118ā126 (1987).
Alvarez, W. & Asaro, F. Scient. Am. 263 (October), 78ā84 (1990).
Hildebrand, A. R. & Boynton, W. V. Science 248, 843ā847 (1990).
Officer, C. B., Hallam, A., Drake, C. L. & Devine, J. D. Nature 326, 143ā149 (1987).
Lewis, R. S., Tang, M., Wacker, J. F., Anders, E. & Steel, E. Nature 326, 160ā162 (1987).
Huss, G. R. Nature 347, 159ā162 (1990).
Gibson, D. W. Geol. Surv. Can. Pap. 76ā35 (1977).
Sweet, A. R. & Jerzykiewicz, T. Geos. 14 (4), 6ā9 (1985).
Lerbekmo, J. F. & St Louis, R. M. Can. J. Earth Sci. 23, 120ā124 (1986).
Lerbekmo, J. F., Sweet, A. R. & St Louis, R. M. Geol. Soc. Am. Bull. 99, 325ā330 (1987).
Grieve, R. A. F. & Alexopoulos, J. Can. J. Earth. Sci. 26, 338 (1989).
Carlisle, D. B. & Braman, D. R. Can. J. Earth. Sci. (in the press).
Smit, J. & Kyte, F. T. Nature 310, 403ā405 (1984).
Hansen, H. J., Gwozdz, R. & Rasmussen, K. L. Revta esp. Palaeontol. spec. Edn 21ā29 (1988).
Bohor, B. F. Tectonophysics 171, 359ā372 (1990).
Lewis, R. S., Anders, E., Shimamura, T. & Lugmair, G. W. Science 222, 1013ā1015 (1983).
Wolbach, W. S., Gilmour, I., Anders, E. Orth, C. J. & Brooks, R. R. Nature 334, 665ā669 (1988).
Badziag, P., Verword, W. S., Ellis, W. P. & Greiner, N. R. Nature 343, 244ā245 (1990).
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Carlisle, D., Braman, D. Nanometre-size diamonds in the Cretaceous/Tertiary boundary clay of Alberta. Nature 352, 708ā709 (1991). https://doi.org/10.1038/352708a0
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DOI: https://doi.org/10.1038/352708a0
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