Ascent of Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary
Paul E. Olsen; Dennis V. Kent; Alessandro Montanari; Emma C. Rainforth; Heinz Huber; Sarah J. Fowell; Hans-Dieter Sues; Christian Koeberl; Michael J. Szajna; Brian W. Hartline
- Ascent of Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary
Olsen, Paul E.
Kent, Dennis V.
Rainforth, Emma C.
Fowell, Sarah J.
Szajna, Michael J.
Hartline, Brian W.
- Lamont-Doherty Earth Observatory
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- Analysis of tetrapod footprints and skeletal material from more than 70 localities in eastern North America shows that large theropod dinosaurs appeared less than 10,000 years after the Triassic-Jurassic boundary and less than 30,000 years after the last Triassic taxa, synchronous with a terrestrial mass extinction. This extraordinary turnover is associated with an iridium anomaly (up to 285 parts per trillion, with an average maximum of 141 parts per trillion) and a fern spore spike, suggesting that a bolide impact was the cause. Eastern North American dinosaurian diversity reached a stable maximum less than 100,000 years after the boundary, marking the establishment of dinosaur-dominated communities that prevailed for the next 135 million years.
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