40Ar/39Ar Age of Cretaceous-Tertiary Boundary Tektites from Haiti

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Science  14 Jun 1991:
Vol. 252, Issue 5012, pp. 1539-1542
DOI: 10.1126/science.252.5012.1539


40Ar/39Ar dating of tektites discovered recently in Cretaceous-Tertiary (K-T) boundary marine sedimentary rocks on Haiti indicates that the K-T boundary and impact event are coeval at 64.5 ± 0.1 million years ago. Sanidine from a bentonite that lies directly above the K-T boundary in continental, coal-bearing, sedimentary rocks of Montana was also dated and has a 40Ar/39Ar age of 64.6 ± 0.2 million years ago, which is indistinguishable statistically from the age of the tektites.