Permafrost in the Cretaceous supergreenhouse

• Published in: Nature Communications
• Main Authors: Rodríguez López, Juan Pedro, Wu, Chihua, Vishnivetskaya, Tatiana A., Murton, Julian B., Tang, Wenqiang, Ma, Chao
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature 2022
• Subjects: Arctic; Ice; permafrost
• Online Access: http://hdl.handle.net/10810/60351; https://doi.org/10.1038/s41467-022-35676-6

Earth’s climate during the last 4.6 billion years has changed repeatedly between cold (icehouse) and warm (greenhouse) conditions. The hottest conditions (supergreenhouse) are widely assumed to have lacked an active cryosphere. Here we show that during the archetypal supergreenhouse Cretaceous Earth, an active cryosphere with permafrost existed in Chinese plateau deserts (astrochonological age ca. 132.49–132.17 Ma), and that a modern analogue for these plateau cryospheric conditions is the aeolian–permafrost system we report from the Qiongkuai Lebashi Lake area, Xinjiang Uygur Autonomous Region, China. Significantly, Cretaceous plateau permafrost was coeval with largely marine cryospheric indicators in the Arctic and Australia, indicating a strong coupling of the ocean–atmosphere system. The Cretaceous permafrost contained a rich microbiome at subtropical palaeolatitude and 3–4 km palaeoaltitude, analogous to recent permafrost in the western Himalayas. A mindset of persistent ice-free greenhouse conditions during the Cretaceous has stifled consideration of permafrost thaw as a contributor of C and nutrients to the palaeo-oceans and palaeo-atmosphere. We thank Yuxiang Shi and Qiushuang Fan for their assistance in the field and helpful discussion. This work was jointly funded by the National Natural Science Foundation of China (Nos. 41872099, 42230310, 41888101, 91855213, 41602127) to Ch.W., Wq.T., C.M. This work is also funded by the “Convocatoria de Ayudas para la recualificación del sistema universitario Español 2021–2023, Financiado por la Unión Europea-Next Generation EU”, Vicerrectorado de Investigación, Universidad del País Vasco UPV/EHU to J.P.R.L. This work is a contribution to the Research Group of the Basque Government IT-1602-22 (Grupo Consolidado del Gobierno Vasco IT-1602-22). This work is partially supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research, Genomic Science Programme under award number DE-SC0020369 to T.A.V. We are grateful to the ...