Arctic ice and the ecological rise of the dinosaurs

• Published in: Science Advances
• Main Authors: Olsen, Paul, Sha, Jingeng, Fang, Yanan, Chang, Clara, Whiteside, Jessica H., Kinney, Sean, Sues, Hans-Dieter, Kent, Dennis, Schaller, Morgan, Vajda, Vivi
• Format: Article in Journal/Newspaper
• Language: English
• Published: Naturhistoriska riksmuseet, Enheten för paleobiologi 2022
• Subjects: Mesozoic; glaciation; climate; dinosaurs; Triassic-Jurassic extinction; Other Earth and Related Environmental Sciences; Annan geovetenskap och miljövetenskap; Arctic
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:nrm:diva-4881; https://doi.org/10.1126/sciadv.abo6342

Abundant lake ice-rafted debris in Late Triassic and earliest Jurassic strata of the Junggar Basin of northwestern China (paleolatitude ~71°N) indicates that freezing winter temperatures typified the forested Arctic, despite apersistence of extremely high levels of atmospheric Pco2 (partial pressure of CO2). Phylogenetic bracket analysis shows that non-avian dinosaurs were primitively insulated, enabling them to access rich deciduous and evergreen Arctic vegetation, even under freezing winter conditions. Transient but intense volcanic winters associated withmassive eruptions and lowered light levels led to the end-Triassic mass extinction (201.6 Ma) on land, decimating all medium- to large-sized nondinosaurian, noninsulated continental reptiles. In contrast, insulated dinosaurs were already well adapted to cold temperatures, and not only survived but also underwent a rapid adaptive radiation and ecological expansion in the Jurassic, taking over regions formerly dominated by large noninsulated reptiles. This is a contribution to UNESCO-IUGS IGCP project 632 and the CycloAstro Project funded by the Heising-Simons Foundation. This work wassupported by the National Natural Science Foundation of China (41730317), the Chinese Academy of Geological Sciences (DD20190009), the Special Basic Program of Ministry of Science and Technology of China (2015FY310100), the Bureau of Geological Survey of China, and the National Committee of Stratigraphy of China (DD20160120-04). The Lamont Climate Center is acknowledged for support to P.O., C.C., and S.K. The LDEO repository is funded by NSF OCE-1259124 and the OSU NSF OCE-1558679. Additional funding was provided by the Heising-Simons Foundation (award no. 2021-2801), the Swedish Research Council (VR grant2019), and the Knut and Alice Wallenberg (KAW) Foundation