Snowball Earth climate dynamics and Cryogenian geology-geobiology.

Autor: Hoffman PF; Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.; School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada., Abbot DS; Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA., Ashkenazy Y; Department of Solar Energy and Environmental Physics, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 84990, Israel., Benn DI; School of Geography and Sustainable Development, University of St Andrews, St Andrews, Fife KY16 8YA, UK., Brocks JJ; Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory 2601, Australia., Cohen PA; Geosciences, Williams College, Williamstown, MA 01267, USA., Cox GM; Centre for Tectonics, Resources and Exploration (TRaX), Department of Earth Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.; Department of Applied Geology, Curtin University, Bentley, Western Australia 6845, Australia., Creveling JR; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331-5503, USA., Donnadieu Y; Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Institut Pierre Simon Laplace (IPSL), CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France.; Aix-Marseille Université, CNRS, L'Institut de recherche pour le développement (IRD), Centre Européen de Recherche et D'enseignement de Géosciences de L'environnement (CEREGE), 13545 Aix-en-Provence, France., Erwin DH; Department of Paleobiology, Smithsonian Institution, P.O. Box 37012, MRC 121, Washington, DC 20013-7012, USA.; Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA., Fairchild IJ; School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK., Ferreira D; Department of Meteorology, University of Reading, Reading, RG6 6BB, UK., Goodman JC; Department of Environmental Science, Wheaton College, Norton, MA 02766, USA., Halverson GP; Department of Earth and Planetary Sciences, McGill University, Montréal, Québec H3A 0E8, Canada., Jansen MF; Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA., Le Hir G; Institut de Physique du Globe de Paris, 1, rue Jussieu, 75005 Paris, France., Love GD; Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, USA., Macdonald FA; Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA., Maloof AC; Department of Geosciences, Princeton University, Princeton, NJ 08544, USA., Partin CA; Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada., Ramstein G; Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Institut Pierre Simon Laplace (IPSL), CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France., Rose BEJ; Department of Atmospheric and Environmental Sciences, University at Albany, Albany, NY 12222, USA., Rose CV; Department of Geology, Trinity College Dublin, Dublin 2, Ireland., Sadler PM; Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, USA., Tziperman E; Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA., Voigt A; Institute of Meteorology and Climate Research, Department of Troposphere Research, Karlsruhe Institute of Technology, Karlsruhe, Baden-Württemberg, Germany.; Lamont-Doherty Earth Observatory, Columbia University, P.O. Box 1000, Palisades, NY 10964-1000, USA., Warren SG; Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195-1640, USA.
Jazyk: angličtina
Zdroj: Science advances [Sci Adv] 2017 Nov 08; Vol. 3 (11), pp. e1600983. Date of Electronic Publication: 2017 Nov 08 (Print Publication: 2017).
DOI: 10.1126/sciadv.1600983
Abstrakt: Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geochemical data imply that CO 2 was 10 2 PAL (present atmospheric level) at the younger termination, consistent with a global ice cover. Sturtian glaciation followed breakup of a tropical supercontinent, and its onset coincided with the equatorial emplacement of a large igneous province. Modeling shows that the small thermal inertia of a globally frozen surface reverses the annual mean tropical atmospheric circulation, producing an equatorial desert and net snow and frost accumulation elsewhere. Oceanic ice thickens, forming a sea glacier that flows gravitationally toward the equator, sustained by the hydrologic cycle and by basal freezing and melting. Tropical ice sheets flow faster as CO 2 rises but lose mass and become sensitive to orbital changes. Equatorial dust accumulation engenders supraglacial oligotrophic meltwater ecosystems, favorable for cyanobacteria and certain eukaryotes. Meltwater flushing through cracks enables organic burial and submarine deposition of airborne volcanic ash. The subglacial ocean is turbulent and well mixed, in response to geothermal heating and heat loss through the ice cover, increasing with latitude. Terminal carbonate deposits, unique to Cryogenian glaciations, are products of intense weathering and ocean stratification. Whole-ocean warming and collapsing peripheral bulges allow marine coastal flooding to continue long after ice-sheet disappearance. The evolutionary legacy of Snowball Earth is perceptible in fossils and living organisms.
Databáze: MEDLINE