Isotopic Evidence for Glaciation During the Cretaceous Supergreenhouse

Andre Bornemann*, Richard D. Norris, Oliver Friedrich, Britta Beckmann, Stefan Schouten, Jaap S. Sinninghe Damste, Jennifer Vogel, Peter Hofmann, Thomas Wagner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

218 Citations (SciVal)

Abstract

The Turonian ( 93.5 to 89.3 million years ago) was one of the warmest periods of the Phanerozoic eon, with tropical sea surface temperatures over 35 degrees C. High- amplitude sea- level changes and positive delta O-18 excursions in marine limestones suggest that glaciation events may have punctuated this episode of extreme warmth. New delta O-18 data from the tropical Atlantic show synchronous shifts similar to 91.2 million years ago for both the surface and deep ocean that are consistent with an approximately 200,000- year period of glaciation, with ice sheets of about half the size of the modern Antarctic ice cap. Even the prevailing supergreenhouse climate was not a barrier to the formation of large ice sheets, calling into question the common assumption that the poles were always ice- free during past periods of intense global warming.

Original languageEnglish
Pages (from-to)189-192
Number of pages4
JournalScience
Volume319
Issue number5860
DOIs
Publication statusPublished - 11 Jan 2008

Keywords

  • ANTARCTIC ICE-SHEET
  • ATMOSPHERIC CO2
  • RECORD
  • OCEAN
  • TEMPERATURES
  • RESOLUTION
  • CALCITE
  • WESTERN
  • CURVE

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