title: Ascent of dinosaurs linked to an iridium anomaly at the Triassic-Jurassic boundary.
abstract: 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.
authors.affiliation: Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
authors.forename: P E
authors.initials: PE
authors.lastname: Olsen
authors.forename: D V
authors.initials: DV
authors.lastname: Kent
authors.forename: H-D
authors.initials: HD
authors.lastname: Sues
authors.forename: C
authors.initials: C
authors.lastname: Koeberl
authors.forename: H
authors.initials: H
authors.lastname: Huber
authors.forename: A
authors.initials: A
authors.lastname: Montanari
authors.forename: E C
authors.initials: EC
authors.lastname: Rainforth
authors.forename: S J
authors.initials: SJ
authors.lastname: Fowell
authors.forename: M J
authors.initials: MJ
authors.lastname: Szajna
authors.forename: B W
authors.initials: BW
authors.lastname: Hartline
mesh_terms: D000818:Animals; D005075:Biological Evolution; D025061:Dinosaurs; D017753:Ecosystem; D029624:Ferns; D005580:Fossils; D019015:Geologic Sediments / Q000737:chemistry; D007495:Iridium / Q000032:analysis*; D019110:Meteoroids; D018543:Minor Planets; D009656:North America; D013170:Spores; D013995:Time
chemical_list: D007495:Iridium