page_title: Tanis (fossil site)
hierarchical_section_title: Tanis (fossil site)
caption_attribution_description: English: Scan of fossil fish from Tanis, showing impact fragments (microtektites) found clustered in the gills of fish at Tanis.
context_page_description: Tanis is the name given to a site of paleontological interest in southwestern North Dakota, United States. Tanis is part of the heavily-studied Hell Creek Formation, a group of rocks spanning four states in North America renowned for many significant fossil discoveries from the Upper Cretaceous and lower Paleocene. Tanis is an extraordinary and unique site because it appears to record the events from the first minutes until a few hours after the impact of the giant Chicxulub meteor in extreme detail. This impact, which struck the Gulf of Mexico about 66 million years ago, wiped out all non-avian dinosaurs and many other species. The extinction event caused by this impact paved the way for the domination of the Earth by mammals, including human beings.
  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 which contained articulated sturgeons, paddlefish and bowfins. These fossils were delivered for research to the Field Museum of Natural History in Chicago.
context_section_description: Tanis is the name given to a site of paleontological interest in southwestern North Dakota, United States. Tanis is part of the heavily-studied Hell Creek Formation, a group of rocks spanning four states in North America renowned for many significant fossil discoveries from the Upper Cretaceous and lower Paleocene. Tanis is an extraordinary and unique site because it appears to record the events from the first minutes until a few hours after the impact of the giant Chicxulub meteor in extreme detail. This impact, which struck the Gulf of Mexico about 66 million years ago, 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 paved the way for the domination of the Earth by mammals, including human beings.
  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 which 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. Other papers describing the site and its fossils are in progress.
  At Tanis, unlike any other known Lagerstätte site, it appears freak circumstances allowed for the preservation of exquisite, moment-by-moment details caused by the impact event. These include many rare and unique finds, which allow unprecedented examination of the direct effects of the impact on plants and animals alive at the time of the large bolide impact some 3000 km distant. The events at Tanis occurred far too soon after impact to be caused by the megatsunamis expected from any large impact near large bodies of water. Instead, much faster seismic waves from the massive magnitude 10 – 11.5 earthquakes probably reached the Hell Creek area as soon as 10 minutes after the impact, creating seiche waves between 10–100 metres (33–328 ft) high in the Western Interior Seaway  and perhaps in other waters nearer Tanis, which was near an ancient river. These waves carried sea, land, and freshwater animals and plants, and other debris several miles inland. The seiche waves exposed and covered the site twice, as millions of tiny droplets and debris from the impact were arriving on ballistic trajectories from their source in what is now the Yucatán Peninsula.
  As of April 2019, reported findings include: 
  animals and plant material preserved in three-dimensional detail and at times upright, rather than pressed flat as usual, their remains thrown together by the massive wave movements;
  articulated and cartilaginous salt and freshwater fish and marine reptiles found together miles inland, with many microtektites (molten debris particles from the impact) embedded in their gills as they tried to breathe;
  millions of "near perfect" primary (that is, not reworked) microtektites "almost indistinguishable" in chemical composition from previously-reported Chicxulub tektites found buried contemporaneous to the fossils in their own impact holes in the soft riverbed mud, and also preserved in amber on tree-trunks;
  large primitive feathers 30–40 cm long with 3.5mm quills believed to come from large dinosaurs;
  broken remains from almost all known Hell Creek dinosaur groups;
  and some incredibly rare finds, such as:
  fossils of hatchlings and intact eggs with embryo fossils;
  fossil pterosaurs for which no other fossils exist at that time;
  drowned ant nest
caption: Fossil fish from Tanis. The fossil shows microtektites (molten splattered glass droplets) which are a chemical match for ejecta from the Chicxulub meteor crater. The microtektites are concentrated in large numbers in the gill rakers of about 50% of sturgeon and paddlefish fossils, and show that the fish were alive when the impact occurred.
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