Alvarez 9505451 This proposal builds on the recognition of the Chicxulub Crater in Yucatan as the probable site of a major impact at the Cretaceous-Tertiary (KT) boundary. The first of two parts of the project will be a detailed study of the products of the KT impact and their mode of origin. Field and laboratory studies of proximal ejecta and the transition from proximal to distal ejecta will be carried out, including inexpensive drilling of a potential KT site at the critical transition distance, and these materials will be tied to formation of the Chicxulub crater by calculations of ballistic trajectories. A key question will be whether the impact was single or multiple, and whether it was steeply inclined or oblique at a low angle. A database of information on KT sites, already well underway, will be expanded and made available to the research community. The second part deals with the environmental results of the KT impact, and will involve both stratigraphic study of the immediate post-impact record in pelagic sedimentary rocks and the preparation of environmental reconstructions of the world immediately before and shortly after the KT boundary impact.
