title: Asian monsoons in a late Eocene greenhouse world.
abstract: The strong present-day Asian monsoons are thought to have originated between 25 and 22 million years (Myr) ago, driven by Tibetan-Himalayan uplift. However, the existence of older Asian monsoons and their response to enhanced greenhouse conditions such as those in the Eocene period (55-34 Myr ago) are unknown because of the paucity of well-dated records. Here we show late Eocene climate records revealing marked monsoon-like patterns in rainfall and wind south and north of the Tibetan-Himalayan orogen. This is indicated by low oxygen isotope values with strong seasonality in gastropod shells and mammal teeth from Myanmar, and by aeolian dust deposition in northwest China. Our climate simulations support modern-like Eocene monsoonal rainfall and show that a reinforced hydrological cycle responding to enhanced greenhouse conditions counterbalanced the negative effect of lower Tibetan relief on precipitation. These strong monsoons later weakened with the global shift to icehouse conditions 34 Myr ago.
authors.affiliation: 1] Institut de Paléoprimatologie, Paléontologie Humaine: Evolution et Paléoenvironnements, UMR CNRS 7262, Université de Poitiers, 86000 Poitiers, France [2] Centre de Recherches Pétrographiques et Géochimiques, UMR CNRS 7358, Université de Lorraine 54501 Vandoeuvre les Nancy, France [3] Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: A
authors.initials: A
authors.lastname: Licht
authors.affiliation: 1] Department of Earth Sciences, Universiteit Utrecht, 3584CD, Utrecht, The Netherlands [2] Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK.
authors.forename: M
authors.initials: M
authors.lastname: van Cappelle
authors.affiliation: 1] Department of Earth Sciences, Universiteit Utrecht, 3584CD, Utrecht, The Netherlands [2] Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven, 3001 Leuven, Belgium.
authors.forename: H A
authors.initials: HA
authors.lastname: Abels
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, UMR CNRS 8212, 91198 Gif-sur-Yvette, France.
authors.forename: J-B
authors.initials: JB
authors.lastname: Ladant
authors.affiliation: Department of Earth Sciences, Durham University, Durham DH1 3LE, UK.
authors.forename: J
authors.initials: J
authors.lastname: Trabucho-Alexandre
authors.affiliation: Centre de Recherches Pétrographiques et Géochimiques, UMR CNRS 7358, Université de Lorraine 54501 Vandoeuvre les Nancy, France.
authors.forename: C
authors.initials: C
authors.lastname: France-Lanord
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, UMR CNRS 8212, 91198 Gif-sur-Yvette, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Donnadieu
authors.affiliation: Department of Earth Sciences, Vrije Universiteit, 1081HV Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Vandenberghe
authors.affiliation: Centre de Recherches Pétrographiques et Géochimiques, UMR CNRS 7358, Université de Lorraine 54501 Vandoeuvre les Nancy, France.
authors.forename: T
authors.initials: T
authors.lastname: Rigaudier
authors.affiliation: Laboratoire de Géologie de Lyon, Terre, Planètes, Environnement, UMR CNRS 5276, Université de Lyon, Institut Universitaire de France, 69622 Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Lécuyer
authors.affiliation: Department of Earth and Environmental Science, Temple University, Philadelphia, Pennsylvania 19122, USA.
authors.forename: D
authors.initials: D
authors.lastname: Terry
authors.affiliation: Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven, 3001 Leuven, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Adriaens
authors.affiliation: Centre de Recherche sur la Paléodiversité et les Paléoenvironnements - UPMC, MNHN, CNRS, 75005 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Boura
authors.affiliation: Key Laboratory of Orogenic Belts and Crustal Evolution, Peking University, 100871 Beijing, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Department of Geology, Defence Services Academy, Pyin Oo Lwin, Myanmar.
authors.forename: Aung Naing
authors.initials: AN
authors.lastname: Soe
authors.affiliation: Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: J
authors.initials: J
authors.lastname: Quade
authors.affiliation: 1] Department of Earth Sciences, Universiteit Utrecht, 3584CD, Utrecht, The Netherlands [2] Key Laboratory of Orogenic Belts and Crustal Evolution, Peking University, 100871 Beijing, China [3] Géosciences Rennes, UMR CNRS 6118, Université de Rennes, 35042 Rennes Cedex, France [4] Universität Potsdam, Institute of Earth and Environmental Science, 14476 Potsdam, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Dupont-Nivet
authors.affiliation: Institut de Paléoprimatologie, Paléontologie Humaine: Evolution et Paléoenvironnements, UMR CNRS 7262, Université de Poitiers, 86000 Poitiers, France.
authors.forename: J-J
authors.initials: JJ
authors.lastname: Jaeger
mesh_terms: D000531:Altitude; D060105:Animal Shells / Q000737:chemistry; D000818:Animals; D002681:China; D002980:Climate; D003889:Desert Climate; D004391:Dust / Q000032:analysis; D005580:Fossils; D049851:Gastropoda / Q000737:chemistry; D017752:Greenhouse Effect / Q000266:history*; D049690:History, Ancient; D002052:Myanmar; D010103:Oxygen Isotopes; D011891:Rain; D012621:Seasons; D013696:Temperature; D018609:Tibet; D014070:Tooth / Q000737:chemistry
chemical_list: D004391:Dust; D010103:Oxygen Isotopes