40Ar-39Ar dating of the Manson impact structure: A cretaceous-tertiary boundary crater candidate
January 1, 1989
The mineralogy of shocked mineral and lithic grains in the Cretaceous-Tertiary (K-T) boundary claystone worldwide is most consistent with a bolide impact on a continent. Both the concentrations and sizes of these shocked grains are greatest in the western interior of North America. These data suggest that the Manson impact structure in north-central Iowa is a viable candidate for the K-T boundary impact event. Argon-40-argon-39 age spectrum dating of shocked microcline from the crystalline central uplift of the Manson impact structure indicates that there was severe argon-40 loss at 65.7 ?? 1.0 million years ago, an age that is indistinguishable from that of the K-T boundary, within the limits of analytical precision.
Citation Information
Publication Year | 1989 |
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Title | 40Ar-39Ar dating of the Manson impact structure: A cretaceous-tertiary boundary crater candidate |
Authors | Michael J. Kunk, G. A. Izett, R. A. Haugerud, J. F. Sutter |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Science |
Index ID | 70015456 |
Record Source | USGS Publications Warehouse |