One of the most important discoveries shedding light on what happened on Earth hours and days after the Cretaceous-Paleogene asteroid impact was made by a young scientist, Robert DePalma. At a locality that he named Tanis in North Dakota he found a tsunami deposit that was triggered by seismic waves in Earth’s interior emanating from the asteroid impact. The tsunamis wave from the Western interior seaway moved up on land along a river valley. At the same time a huge, hundred meters high “curtain” of magma and ash from the Chicxulub impact crater passed by at a speed of 10,000 kilometres per hour. The tsunamis deposit that Robert found contains a chaotic mixture of freshwater and marine animals together with billions of microscopic glass spherules that condensed from the magma cloud on its way northward. A BBC documentary starring David Attenborough and Robert tells the story about the Tanis site, The Last Day of the Dinosaurs. In the second week of August 2023 Birger Schmitz visited the Tanis locality together with Robert to see with his own eyes. Everything as described by Robert was there, including a footprint by a small three-toed dinosaur just at the base of the tsunamis deposit. This was one of the probably most exiting experiences a geologist can have.
Link to paper: A seismically induced onshore surge deposit at the KPg boundary, North
Dakota by Robert DePalma et al. in Proceedings of the National Academy of Sciences, 2019.
https://www.pnas.org/doi/10.1073/pnas.1817407116
Link to editorial article in Science where accusations against Robert DePalma are laid out for having fabricated data for an article claiming the Chicxulub impact took place in spring: