Tanis (fossil site)

Tanis is the informal name for a paleontological site located in southwestern North Dakota, USA, within the Hell Creek Formation. It gained significant attention starting in 2019 due to claims that it contains exceptionally well-preserved fossils of organisms killed by the Chicxulub impact event, which is widely believed to have triggered the Cretaceous-Paleogene extinction event (K-Pg extinction event) approximately 66 million years ago.

The site is notable for its purported preservation of fossils in a manner consistent with a catastrophic event, potentially capturing a snapshot of life immediately before and during the impact. This includes purportedly fossilized fish with impact ejecta particles lodged in their gills, as well as other organisms such as turtles, mammals, dinosaurs, and trees.

However, the interpretations of the Tanis site have generated considerable scientific debate. While the presence of K-Pg boundary sediments and evidence of a significant geological event at the site are generally accepted, the specific mechanisms of fossil preservation, the precise timing relative to the impact, and the claims of extraordinary preservation are subjects of ongoing research and discussion within the paleontological community. Some scientists have questioned the evidence supporting a direct link to the Chicxulub impact, suggesting that other geological processes, such as fluvial activity and local flooding, may have played a more significant role in the formation of the fossil deposit.

Further research and rigorous peer review are crucial to fully understand the Tanis site and its implications for understanding the K-Pg extinction event.