Climatic ups and downs in a disturbed Jurassic world.

• Published in: Geology
• Main Authors: Dera, Guillaume, Brigaud, Benjamin, Monna, Fabrice, Laffont, Rémi, Pucéat, Emmanuelle, Deconinck, Jean-François, Pellenard, Pierre, Joachimski, Michael M., Durlet, Christophe
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Biogéosciences UMR 6282 Dijon (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Archéologie, Terre, Histoire, Sociétés Dijon (ARTeHiS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-Ministère de la Culture et de la Communication (MCC), GeoZentrum Nordbayern, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDE.MCG]Environmental Sciences/Global Changes; Ice cap; Polar Ice Cap
• Online Access: https://hal.archives-ouvertes.fr/hal-00565862; https://doi.org/10.1130/G31579.1

4 pages International audience The tropical, warm, and equable climate of the Jurassic world is regularly challenged by geoscientists, especially since oxygen isotopes ( 18O) of fossil hardparts have been used to reconstruct the paleotemperature history of seawater. By applying the innovative “SiZer” (significant zero crossings of the derivatives) statistical approach to a newly compiled 18O database for the Jurassic, we demonstrate the occurrence of major and multiscale 18O changes mainly related to climate disturbances. For the first time, two long-term anomalies in 18O are identified during the Toarcian and the Late Jurassic, in conjunction with intensive volcanism in large igneous provinces. These results support a strong influence of repeated volcanic pulses on the modulation of pCO2, temperatures, and polar ice cap volumes over protracted periods. At shorter time scales, 13 relatively rapid (0.5–1 m.y.) and significant warming and cooling events are identified, the causes of which include transient fluctuations in greenhouse gas concentrations related to still-debated mechanisms.