Olsen P E, Kent D V, Sues H-D, Koeberl C, Huber H, Montanari A, Rainforth E C, Fowell S J, Szajna M J, Hartline B W
Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
Science. 2002 May 17;296(5571):1305-7. doi: 10.1126/science.1065522.
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.
对北美东部70多个地点的四足动物足迹和骨骼材料的分析表明，大型兽脚亚目恐龙在三叠纪-侏罗纪边界之后不到10000年出现，在最后一个三叠纪类群之后不到30000年出现，与一次陆地生物大灭绝同时发生。这种异常的更替与铱异常（高达万亿分之285，平均最大值为万亿分之141）和蕨类孢子峰值有关，表明是一次小行星撞击导致的。北美东部恐龙多样性在边界之后不到100000年达到稳定的最大值，标志着恐龙主导群落的建立，这种群落持续了接下来的1.35亿年。
