Article abstract


Nature Geoscience 2, 589 - 594 (2009)
Published online: 13 July 2009 | doi:10.1038/ngeo577

Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism

B. van de Schootbrugge1, T. M. Quan2, S. Lindström3,4, W. Püttmann1, C. Heunisch5, J. Pross1, J. Fiebig1, R. Petschick1, H.-G. Röhling5, S. Richoz1, Y. Rosenthal2 & P. G. Falkowski2


One of the five largest mass extinctions of the past 600 million years occurred at the boundary of the Triassic and Jurassic periods, 201.6 million years ago. The loss of marine biodiversity at the time has been linked to extreme greenhouse warming, triggered by the release of carbon dioxide from flood basalt volcanism in the central Atlantic Ocean. In contrast, the biotic turnover in terrestrial ecosystems is not well understood, and cannot be readily reconciled with the effects of massive volcanism. Here we present pollen, spore and geochemical analyses across the Triassic/Jurassic boundary from three drill cores from Germany and Sweden. We show that gymnosperm forests in northwest Europe were transiently replaced by fern and fern-associated vegetation, a pioneer assemblage commonly found in disturbed ecosystems. The Triassic/Jurassic boundary is also marked by an enrichment of polycyclic aromatic hydrocarbons, which, in the absence of charcoal peaks, we interpret as an indication of incomplete combustion of organic matter by ascending flood basalt lava. We conclude that the terrestrial vegetation shift is so severe and wide ranging that it is unlikely to have been triggered by greenhouse warming alone. Instead, we suggest that the release of pollutants such as sulphur dioxide and toxic compounds such as the polycyclic aromatic hydrocarbons may have contributed to the extinction.

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  1. Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, D-60438 Frankfurt am Main, Germany
  2. Institute of Marine and Coastal Sciences, Rutgers, the State University of New Jersey, 71 Dudley Road, New Brunswick, New Jersey 08901, USA
  3. GeoBiosphere Science Centre, Department of Geology, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden
  4. Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen, Denmark
  5. State Authority for Mining, Energy and Geology, Stilleweg 2, D-30655 Hannover, Germany

Correspondence to: B. van de Schootbrugge1 e-mail: van.de.Schootbrugge@em.uni-frankfurt.de



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