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Title

Secular environmental precursors to Early Toarcian (Jurassic) extreme climate changes

Publication Year

2010

Author(s)
  • Suan, Guillaume
  • Mattioli, Emanuela
  • Pittet, Bernard
  • Lecuyer, Christophe
  • Sucheras-Marx, Baptiste
  • Duarte, Luis Vitor
  • Philippe, Marc
  • Reggiani, Letizia
  • Martineau, Francois
Source
EARTH AND PLANETARY SCIENCE LETTERS Volume: 290 Issue: 3-4 Pages: 448-458 Published: 2010
ISSN
0012-821X
Abstract

The Early Toarcian Oceanic Anoxic Event (T-OAE), about 183 myr ago, was a global event of environmental and carbon cycle perturbations, which deeply affected both marine biota and carbonate production. Nevertheless, the long-term environmental conditions prevailing prior to the main phase of marine extinction and carbonate production crisis remain poorly understood. Here we present a similar to 8 myr-long record of Early Pliensbachian-Middle Toarcian environmental changes from the Lusitanian Basin, Portugal, in order to address the long-term paleoclimatic evolution that ultimately led to carbonate production and biotic crises during the T-OAE. Paleotemperature estimates derived from the oxygen isotope compositions of well-reserved brachiopod shells from two different sections reveal a pronounced similar to 5 degrees C cooling in the Late Pliensbachian (margaritatus-spinatum ammonite Zones boundary). This cooling event is followed by a marked similar to 7-10 degrees C seawater warming in the Early Toarcian that, after a second cooling event in the mid-polymorphum Zone, culminates during the T-OAE. Calcium carbonate (CaCO(3)) contents, the amount of nannofossil calcite and the mean size of the major pelagic carbonate producer Schizosphaerella, all largely covary with paleotemperatures, indicating a coupling between climatic conditions and both pelagic and neritic CaCO(3) production. Furthermore, the cooling and warming episodes coincided with major marine regressions and transgressions, respectively, suggesting that the growth and decay of ice caps may have exerted a strong control on sea-level fluctuations throughout the studied time interval. This revised chronology of environmental changes shows important similarities with Neogene and Paleozoic episodes of deglacial black shale formation, and thus prompts the reevaluation of ice sheet dynamics as a possible agent of Mesozoic events of extinction and organic-rich sedimentation. (C) 2010 Elsevier B.V. All rights reserved.

Author Keyword(s)
  • Pliensbachian-Toarcian
  • stable isotopes
  • paleotemperature
  • carbon cycle
  • glacio-eustasy
  • carbonate production
KeyWord(s) Plus
  • OCEANIC ANOXIC EVENT
  • MODERN BRACHIOPOD SHELLS
  • CALCAREOUS NANNOFOSSILS
  • SEA-LEVEL
  • MASS EXTINCTIONS
  • ATMOSPHERIC CO2
  • NORTHERN SPAIN
  • BLACK SHALES
  • BASIN
  • PHYTOPLANKTON
ESI Discipline(s)
  • Geosciences
Web of Science Category(ies)
  • Geochemistry & Geophysics
Adress(es)

[Suan, Guillaume; Mattioli, Emanuela; Pittet, Bernard; Lecuyer, Christophe; Sucheras-Marx, Baptiste; Philippe, Marc; Reggiani, Letizia; Martineau, Francois] Univ Lyon 1, Lab CNRS UMR PaleoEnvironm & PaleobioSphere, F-69622 Villeurbanne, France; [Duarte, Luis Vitor] Univ Coimbra, Fac Ciencias & Tecnol, IMAR CMA, Dept Ciencias Terra, P-3000272 Coimbra, Portugal; [Reggiani, Letizia] Univ Perugia, Dipartimento Sci Terra, I-06123 Perugia, Italy

Reprint Adress

Suan, G (reprint author), Univ Lausanne, Inst Geol & Palaeontol, CH-1015 Lausanne, Switzerland.

Country(ies)
  • France
  • Italy
  • Portugal
  • Switzerland
CNRS - Adress(es)
  • Laboratoire de géologie de Lyon : Terre, planètes et environnement (LGL-TPE), UMR5276
Accession Number
WOS:000275306200020
uid:/T8CVJJRT
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