The Chicxulub Impact Produced a Powerful Global Tsunami

An approximately 14-km diameter asteroid is implicated in the Cretaceous/Paleogene (K/Pg) mass extinction, where it struck in shallow water off of the Yucatan Peninsula. Here, we present what is, to our knowledge, the first global simulation of the Chicxulub impact tsunami. We use the axisymmetric iSALE-2D hydrocode to simulate the initial formation of the Chicxulub impact tsunami. The hydrocode results at ten minutes post-impact are merged with 66 Ma bathymetry into a shallow-water model, the Geophysical Fluid Dynamics Laboratory (GFDL) Modular Ocean Model Version 6 (MOM6), to trace the tsunami's propagation throughout the world ocean. The paleobathymetry came from a combination of the PALEOMAP dataset, where present-day crust is used to reconstruct 66 Ma crust, and the Muller et al. dataset, which uses basin-age depth relations to construct the 66 Ma bathymetry. The impact tsunami spread quickly out of the Gulf of Mexico into the Atlantic and through the Central American seaway into the Pacific within the first 24 hours. Wave reflection and refraction create a more complex tsunami propagation pattern by 48 hours post-impact. Flow velocities exceeded 20 cm/s along shorelines worldwide and may have disturbed sediments over 6000 km from the impact origin. In open-ocean areas in the Tethyian region, the South Atlantic, the North Pacific, and the Indian Ocean appear geographically protected from high flow velocities. Compared to the December 26, 2004 Indian Ocean tsunami, one of the largest tsunamis in the modern record, the impact tsunami was approximately 2600 times more energetic. We are hopeful that these records may be able to indicate if the impact tsunami model propagation and magnitude is consistent with various upper-Cretaceous sediments found around the world. This model suggests that the bolide impact not only had major effects on the global atmosphere and biosphere, it also created a tsunami of such magnitude that its effect is felt across much of the world ocean.