Tanis (fossil site)

Tanis is a paleontological site in southwestern North Dakota, United States. It is part of the heavily studied Hell Creek Formation, a geological region renowned for many significant fossil discoveries from the Upper Cretaceous and lower Paleocene. Uniquely, Tanis appears to record in detail, extensive evidence of the effects of the giant Chicxulub asteroid impact which struck the Gulf of Mexico 66.043 million years ago, and wiped out all non-avian dinosaurs and many other species (the so-called "K-Pg" or "K-T" extinction). The extinction event caused by this impact began the Cenozoic, in which mammals - including humans - would eventually come to dominate life on Earth. The site was originally discovered in 2008 by University of North Georgia Professor Steve Nicklas and field paleontologist Rob Sula. Their team successfully removed fossil field jackets that contained articulated sturgeons, paddlefish, and bowfins. These fossils were delivered for research to the Field Museum of Natural History in Chicago. Recognizing the unique nature of the site, Nicklas and Sula brought in Robert DePalma, a University of Kansas graduate student, to perform additional excavations. The site was systematically excavated by Robert DePalma over several years beginning in 2012, working in near total secrecy. Key findings were presented in two conference papers in October 2017. The full paper introducing Tanis was widely covered in worldwide media on 29 March 2019, in advance of its official publication three days later. The co-authors included Walter Alvarez and Jan Smit, both renowned experts on the K-Pg impact and extinction. At Tanis, unlike any other known Lagerstätte site, it appears specific circumstances allowed for the preservation of exquisite, moment-by-moment details caused by the impact event. These include finds, which allow examination of the direct effects of the impact on plants and animals alive at the time of the large impact some distant. The events at Tanis occurred too soon after impact to be caused by the megatsunamis expected from any large impact near large bodies of water.