Romain Amiot et al., PNAS, Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates

Proceedings of the National Academy of Sciences, published online before print March 10, 2011; doi: 10.1073/pnas.1011369108

Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates

1. Romain Amiot^a,¹,², 
2. Xu Wang^b, 
3. Zhonghe Zhou^a, 
4. Xiaolin Wang^a,
5. Eric Buffetaut^c, 
6. Christophe Lécuyer^d,², 
7. Zhongli Ding^b,
8. Frédéric Fluteau^e, 
9. Tsuyoshi Hibino^f, 
10. Nao Kusuhashi^g, 
11. Jinyou Mo^h,
12. Varavudh Suteethornⁱ, 
13. Yuanqing Wang^a, 
14. Xing Xu^a, and 
15. Fusong Zhang^b

1. ^aKey Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), 142 Xi Zhi Men Wai DaJie, Beijing 100044, China;
2. ^bKey Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, 19 Beitucheng Xilu, Beijing 100029, China;
3. ^cCNRS (Centre National de la Recherche Scientifique) UMR (Unité Mixte de Recherche) 8538, Laboratoire de Géologie de l’Ecole Normale Supérieure, 24, Rue Lhomond, 75231 Paris Cedex 05, France;
4. ^dCNRS (Centre National de la Recherche Scientifique) UMR (Unité Mixte de Recherche) 5125, Université Claude Bernard Lyon 1, 2, Rue Raphaël Dubois, 69622 Villeurbanne Cedex, France;
5. ^eInstitut de Physique du Globe de Paris, 1 Rue Jussieu, 75238 Paris Cedex 05, France;
6. ^fShiramine Institute of Paleontology, Kuwajima, Hakusan, Ishikawa 920-2502, Japan;
7. ^gDepartment of Earth's Evolution and Environment, Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan;
8. ^hFaculty of Earth Sciences, China University of Geosciences, 388 Lumo Road, Wuhan 430074, China; and
9. ⁱDepartment of Mineral Resources, Rama VI Road, Bangkok 10400, Thailand

1. Edited by Paul E. Olsen, Columbia University, Palisades, NY, and approved November 4, 2010 (received for review August 3, 2010)

Abstract

Early Cretaceous vertebrate assemblages from East Asia and particularly the Jehol Biota of northeastern China flourished during a period of highly debated climatic history. While the unique characters of these continental faunas have been the subject of various speculations about their biogeographic history, little attention has been paid to their possible climatic causes. Here we address this question using the oxygen isotope composition of apatite phosphate (δ) from various reptile remains recovered from China, Thailand, and Japan. δ values indicate that cold terrestrial climates prevailed at least in this part of Asia during the Barremian—early Albian interval. Estimated mean air temperatures of about 10 ± 4 °C at midlatitudes (∼42° N) correspond to present day cool temperate climatic conditions. Such low temperatures are in agreement with previous reports of cold marine temperatures during this part of the Early Cretaceous, as well as with the widespread occurrence of the temperate fossil wood genus Xenoxylon and the absence of thermophilic reptiles such as crocodilians in northeastern China. The unique character of the Jehol Biota is thus not only the result of its evolutionary and biogeographical history but is also due to rather cold local climatic conditions linked to the paleolatitudinal position of northeastern China and global icehouse climates that prevailed during this part of the Early Cretaceous. 

http://www.pnas.org/content/108/13/5179.abstract