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Science 30 July 1993:
Vol. 261. no. 5121, pp. 595 - 598
DOI: 10.1126/science.261.5121.595
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Articles

Detection of a Meteoritic Component in Ivory Coast Tektites with Rhenium-Osmium Isotopes

Christian Koeberl 1 and Steven B. Shirey 2

1 Institute of Geochemistry, University of Vienna, Dr.-Karl-Lueger-Ring 1, A-1010 Vienna, Austria, and Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015
2 Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015

Measurement of rhenium (Re) and osmium (Os) concentrations and Os isotopic compositions in Ivory Coast tektites (natural glasses with upper crustal compositions that are ejected great distances during meteorite impact) and rocks from the inferred source crater, Lake Bosumtwi, Ghana, show that these tektites incorporate about 0.6 percent of a meteoritic component. Analysis of elemental abundances of noble metals alone gives equivocal results in the detection of meteoritic components because the target rocks already have relatively large amounts of noble metals. The Re-Os system is ideally suited for the study of meteorite impacts on old continental crust for three reasons. (i) The isotopic compositions of the target rocks and the meteoritic impactor are significantly different. (ii) Closed-system mixing of target rocks and meteorites is linear on Re-Os isochron diagrams, which thus permits identification of the loss of Re or Os. (iii) Osmium isotopic compositions are not likely to be altered during meteorite impact even if Re and Os are lost.

Submitted on March 12, 1993
Accepted on June 4, 1993


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Meteorite cratering: Hooke, Gilbert, Barringer and beyond.
G. J. H. McCall (2006)
Geological Society, London, Special Publications 256, 443-469
   Abstract »    PDF »
The history of tektites.
G. J. H. McCall (2006)
Geological Society, London, Special Publications 256, 471-493
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Pronounced central uplift identified in the Bosumtwi impact structure, Ghana, using multichannel seismic reflection data.
C. A. Scholz, T. Karp, K. M. Brooks, B. Milkereit, P. Y.O. Amoako, and J. A. Arko (2002)
Geology 30, 939-942
   Abstract »    Full Text »    PDF »
Mineralogical and geochemical aspects of impact craters.
C. Koeberl (2002)
Mineralogical Magazine 66, 745-768
   Abstract »    Full Text »    PDF »
Identification of meteoritic components in impactites.
C. Koeberl (1998)
Geological Society, London, Special Publications 140, 133-153
   Abstract »    PDF »


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