The Chicxulub impact event and the environmental catastrophe at the end of the Cretaceous Period
AdvisorMelosh, H. Jay
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractImpact events may have affected the evolution of life on Earth. The mass extinction event at the end of the Cretaceous Period, which includes the demise of the dinosaurs, has been linked to the large impact event that produced the Chicxulub structure located in the Yucatán Peninsula, Mexico. Unfortunately, the geologic record is too spotty to prove any causal relation between the impact event and the mass extinction event that occurred 65 Myr ago. However, the size and location of the impact structure have drawn attention to impact-related abrupt perturbations of the climate and their effects on the biota. My main approach to studying these impact-related perturbations is through hydrocode models of the impact event. Few simulations of the Chicxulub impact event have previously been done. In these simulations the event was modeled as an asteroid impact, using two-dimensional hydrocodes that permit modeling only vertical impacts (i.e. perpendicular to the surface). This work presents the results of a series of high-resolution two- and three-dimension hydrocode simulations of the Chicxulub impact event. The simulations span several different projectile sizes, cover asteroid as well as comet impacts, and explore the effects of impact angle on the impact event. The focus of the simulations is to obtain reliable estimates of the climatically active gases, namely S-bearing gases, CO₂ and water vapor, released to the atmosphere by the impact event. These estimates will be used in modeling the perturbation of the climate of the end of the Cretaceous, and, hopefully, will shed new light on the relation between the impact event and the mass extinction that occurred 65 Myr ago.
Degree ProgramGraduate College