Date of Award


Degree Type


Degree Name

Master of Science in Aeronautics and Astronautics


Aeronautics and Astronautics

First Advisor

Alina Alexeenko

Committee Chair

Alina Alexeenko

Committee Member 1

Henry J. Melosh

Committee Member 2

Gregory Blaisdell


The Chicxulub impact 66.0 million years ago initiated the second biggest extinction in the Phanerozoic Eon. The global reentry of material ejected by the impact generated a strong pulse of thermal radiation that wiped out much of the terrestrial biota. The cause of the marine extinction, however, has remained elusive. This report shows that reentering ejecta produces enough NOx to acidify the upper ocean and cause a massive marine extinction. Using non-equilibrium chemically reacting flow simulations coupled with atmospheric transport modeling, it is determined that enough NOx reached the stratosphere and precipitated to overpower the carbonate buffer and acidify the upper ocean down to a pH of 6.7, causing most organisms to perish.