Cretaceous--Tertiary Boundary Studies Building on Recognition of the Chicxulub--Impact Crater

这一建议是建立在尤卡坦的希克苏鲁伯陨石坑可能是白垩纪-第三纪（KT）边界上一次重大撞击的基础上的。该项目的第一部分将是详细研究KT撞击的产物及其起源模式。将进行近端喷射物和从近端喷射物到远端喷射物的过渡的实地和实验室研究，包括在临界过渡距离上对潜在的KT地点进行廉价钻探，并通过弹道轨迹计算将这些材料与希克苏鲁伯陨石坑的形成联系起来。一个关键的问题是，撞击是单一的还是多重的，以及撞击是陡斜的还是低角度的。已经在进行中的KT网站信息数据库将扩大并提供给研究界。第二部分涉及第三纪碰撞的环境结果，包括对撞击后的上层沉积岩记录的地层学研究，以及在第三纪边界碰撞之前和之后不久的世界环境重建的准备。

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.